Houdini MPM Mud Simulation

1. 01 Introduction: Hello, and welcome to this Houdini course. My name is hazard Amer, and I will be your instructor throughout this course. We will start this course off by first creating the terrain and then we will prepare our Jeep model for RBD Bullets and we are going to be using Houdini RBD Kari to dynamically animate our Jeep, and here we will see how to animate friction over time to create Jeep wheel sleeping effect. Then I will give you a brief overview of Houdini MPM solver before creating our actual effect. And then we will start creating our APM mud simulation by first creating proper source and initial state of our mud. And after that, we will see how we can fix our collider mesh pad topology that you might face when creating dynamic collider. And once we have our APM mud simulation, then we'll see how we can generate wet map for creating wet mud effect, and I will show you different techniques for generating wet map. And after that, we will scatter some grass and rocks for our environment, and we will finish our course of by importing all of our acid into Solaris for rendering and we will use Kerma xBU to render and finish our project. And I, We got a lot to cover. So without further ado, let's dive right in. And I will see you in the very first lesson. 2. 02 Download Assets: Let's download some assets that we are going to need for our project, and I am in here in the site called Polly Haven. And in here, we are going to download the HDRI, some of the textures as well as some of the models. And for the HDRI, I am going to use the HDRI. This one, a horn Stag. I don't know how to pronounce it correctly. A horn stage, a horn stag, something like that. Can search this by typing this Ahn, and here you will see a horn stage. And let's go into the HDRI, and in here, we can select the resolution. Right now, it's set to four K, and we do not need that four K because we are going to just light our scene using this HDRI. So downloading the two k is enough for us, and in here, we can select the file type and EXR is good. You can download the HDR if you like, but EXR is fine as well. Let's download this. And for the material, I am going to use this material. Let me find. Let me scroll it down. First one, this one, brown mud leaves 01. And I am also going to use this forest ground 01, these two material. Here we have this brown mud lead 01 material. And in here, right now, we selected the blender file. I can change this to zip. We need the zip file. And in here, we can set which file we want to download. And we do not need this blend file, and we also do not need this GLTF. We only need these maps for all materials and Amboclusion JPEG, you can select the EXR or PNG. And for this one, JPEG works fine for us, and I am only going to select the EXR for the normal and for the roughness only because these are the material that will actually contain some of the values that is needed for creating the normal as well as roughness map. So let's change this to EXR. And four K resolution is good, and let's download this. Same thing with this one, Forest ground 01. Let's change the file type from blend to Zip and four K, and we have all of these maps selected. Let's download this. And for the model, I'm going to use this model called Rock Moss set 01. We have the blend file in here as well. So let's change this to Zip and we can uncheck the blend file as well as GLTF and we are going to use the FPX models. And here we have the materials, and all of these materials are just fine in the JPEG format, only the normal and roughness into EXR. I'm also going to use this one cross Medium 02, and you can download this again by changing this to Zip and FBX. And lastly, we need the Jeep model, and I am using the Jeep model from Sketchfab. I will provide you the link. You can download this. And if I scroll down, here we have the option to download this three D model. Let's click on it. And here we have some of the formats. We have the FBX, as well as USDZ I am going to download the USDZ format because it's an very lightweight. It's only 11 megabyte, and it will work fine for us. Let's download the USDZF let's download all of these assets, and I will see you in the next lesson. 3. 03 Create Terrain: Let's start this project off by first creating a new project, and for that, let's go into the file in here, let's click on this new project, and here we have this new window, and in here, you can set the path where you want to create all of these folder and Houdini will create this geometry as well as all of these folder for organizing our simulation, as well as our whole project. And in here, we can set the name. I'm going to name this 1:00 P.M. MUD. That will be our project name. And in the path, I'm using this T for my documents file, and in here, I have created this folder called Houdini prorojects in here, we are going to create this MPM MUD project, and let's hit Accept. And now that we have set it this project file directory, we can now save this HIP file as well. And for that, let's go into the file, and let's change this one save. And here as you can see now onto the doll assign job, we are in the folder where we have created this project. And I'm going to create this HIP file in here onto the root folder, and I'm going to call this 1:00 P.M. MUD as well. So let's type MPM underscore Ud. And let's hit except to save. And now we have our Hip file save. And let's start creating our terrain. And for that, I'm going to first create an Ajomtr node. Let's add an ageometry and let's dive inside, and now we are in the geometry context. And in here, I'm going to use the height field, how doin height field built in height field nodes. So let's in here, type the height, and here we have the height field. Let's add this. And by default, it will create a very large size. So onto the viewboard, press F, and that will frame our entire this grid. And onto the height field, let's enable the parameter by pressing the PK and onto the inhere, we have the orientation as well as all of the initial height. We can set the initial height if we want to move it up. But all of these default values are fine. I'm going to leave them as is. And onto the size, here you can see, we have the thousand meter by 1,000 meter, which means that this height field patch is 1 kilometer long. And let's leave it as is because all of the height field node are designed to work with this large scale. And if we are going to scale it down later on, we will have some problems. So let's keep it as is. And in here, let's add an A noise by typing an height field noise node. Let me type this correctly. Height field noise. Let's add this and connect this in here and view the result. And if I zoom in, let me hide the grade for now right now and we can see our noise has been added. I can increase the amplitude to create an A more high amplitude of these mountains. Now we have bigger peaks and valleys. But for our project, we do not need that big mountain. We only need an aground. And for that, I'm going to change my amplitude to a very low value. I'm going to keep lowering this down. And where we have an slide, all of these pumps and not too much. And I'm going to change this value to 107. And right now it is very hard to see. And we can change, actually, it's visualization by clicking on this i button. And let's go into our material section. And here we have the diffuse, and I'm going to change diffuse to a very light color. Let's close this, close it in here. And here I think you can see that we have some of the noise introduced if I increase this. And now, here you can clearly see that we have this noise working, and I'm going to lower this value down to 107. And we also need channel in here where our water will be flowing and our Jeep our Jeep will go through that water and for creating this channel, let's add height field paint node to paint this channel. And for that, let's add height field paint node. Here we have t field paint node, and let's add this, and maybe we are going to add this first in here and let's let this node and hover over to the viewport and press Enter to activate it this brush size. I'm going to paint this mask so right now, the size is not our size is very small, and to increase the size, I'm going to increase the radius. Let's increase this, and I'm going to paint it. And right now we have a very soft brush, and for that, I'm going to open up parameter. And onto the soft edge, I'm going to lower this value down. Let's paint this and maybe let's increase this 20.5. And let's add an A stroke into the center. And right now I think it is an A too thick stroke. So maybe let's lower down the radius. I'm going to lower down the radius to value of 100. Let's paint this. And I think that value is fine. And now it will create an a layer that will call mask. If I middle mouse button here as can see we have a new layer that is called mask, and here we can define the name, and that is the mask. And now we can use the height field noise. Not to apply the noise onto this mask. And the second input is for the mask input. If I attach this inhere onto the height field noise, and right now, hers can see where we have the mask. Our noise is only going to be applied wherever we have this value red, and we need the invert of that. And for that, we have anode called Height field mask invert. Here we have height field mask invert, and that will invert our mask. And I'm going to connect this inhale. And heres can see we have an A inverted mask, and now, which means I can connect this in here and hers can see. Now I can apply the amplitude, and hers can see where we have the mask. We are not adding any noise in here. And for that, I'm going to lower this value down to 107 by default. And in here as you can see that this mask is right now a bit boring. We do not have an much breakup. It's in a very straight line. And to actually break up our mask, we have node called height field distorted. Right here, if I type distorted, and here we have this node called height field distorted by noise. We have this one called distorted Bayer, and we have the height field distorted by noise, and we need this one distorted by noise. Let's add this, and I'm going to add this in here and view this result. And right now it is distorting our height layer, and if I enable this, and right now it is hard to see, but it is distorting this height, but we want to distort this mask layer. So onto the layer, it says, height. We are going to rename these two mask because that is the layer we want to distort. And here as you can see we have some distortion going on. And right now it is a very high value and we get in some large breakups and we do not need them. So let's keep lowering this value down. And I think I'm going to lower this value down to 24. And that will give us some of these nice breakups, and that will create natural looking channel. So now let's rearrange these nodes graph, and I'm going to remove all of these wires. We are going to connect them again. And first, I think we are going to use the height field mask invert node where we have inverted our mask, and now I'm going to add height field distorted node. And here as you can see we have the distortion going on, and by the way, you can add this in here as well if you want. And then you can add an A mask invert node, but I'm going to add this after we have inverted this, and that way we do not get this breakup in hair. And now, Hears can see the height ful distort node has added the distortion onto our T corner as well, and we do not want that. And to fix this, we are going to add another height field paint node. So let me grab this and add this height field paint node in here, connect this and I'm going to press Enter, and let's increase the brush size, where we have the radius. Let's increase this, and I'm going to fill these values because we don't want distortion in here. We want all of these values to be completely red, which means that our noise will going to be applied in here, and we want the noise to be applied. And let's fill all of these. And now we can finally add the height field noise node. Let's connect this, and by default, it will add the noise where we have all of these, where we have onto all of our geometry, if I increase the amplitude, here is can see and to actually add the mask, we need to connect the mask input as well. That is the second input, and it is coming from the same input. Heres can see now we are only adding the noise where we have this red mask. Let's go back and I'm going to lower down the amplitude to our value that we like, and that is the hundred and seven. Now that we have added this noise, we are going to need this center mask later when we are going to create an A water and for that, I'm going to add an A mask invert node again. Let's add a height field mask invert. Let's set this and connect this. That will give us the water line, and we are going to use this to extrude this piece to create an A water. And onto the height field mask. W node after that, and by the way, if this looks too wide for you, you can add a shrink node in here. So in here, I'm going to add an mask shrink node. Here we have the height field mask. Shrink node. Let's side this and connect this after that. And heroes can see we can add the shrink amount. And I think we might need to add a little bit of shrinkiness and the default value is fine. Let's keep it as it is. And the only thing now left to do is to let's move this water line down. Right now, hers you can see, we have a flat surface and we want this to be and move down version. And for that, we have a node called clip. So let's add height field clip node. Here we have the height field clip. Let's set this and connect this into this clip node, as well as let's add the mask input because we are going to only want to clip this mask section. Let me enable the parameter, and onto the clip here, we can define the max, but we want to move this down, which means we need the values in the negative. So if I were to let's change the two minus two, and here is can see, let me keep lowering this value down. Let's lower this down, and Hers can clearly see that now we are moving these values down. So maybe let's not move them that much. I'm going to let's change this to -26. And I think that will create an enough water line for us. That is the I think that depth is correct. And with that, this terrain has been finished. And so now let's scale this or whole terrain back because right now here as you can see we have this A. Here as you can see, we have the size, and that is 1,000 in X as well as 1,000 in Z. So we have an A 1 kilometer long or this train, and we do not want that much. That big size. And for that, I'm going to use an A transform node to scale down our overall transform, scale down this overall terrain. Let's connect this in here. And by using this transform, we can increase or decrease our height field uniform scale. And I'm going to lower this value down to lower value to 0.0 15 and press F to frame this, let me zoom in and here you can see now we have an A manageable scale. Because later on we are going to use the MPM simulation as well as RBD, so the scale is important. And if I were to middle mouse button, now here as you can see, we have a 15 meter by 15 meter of this terrain, and I think that is an manageable size. After that, let's create null at the end. I'm going to rename this our height field. In here, let's type this out height field, and that is an volume representation of this terrain. And we are going to use this null to reference in the RBD to create to add this as an collider and after that, Loon let's convert this into geometry because for rendering, as well as adding some water line, as well as some of the extrusion and mud, all of these we need this in geometry because we are also going to shade this and we also need the jus. And for that, we need the polygonal geometry and not this volume representation terrain. And for that, we have a node called height field. Convert node. Let me type this again, height field, convert height field. Let's add this and connect this and now this height field convert node will convert this into polygonal geometry, and here as you can see now we have this polygonal geometry and we also have UVs, and that will be our terrain for rendering. So in here, I'm going to create another null node, and I'm going to call this one out terrain. And that will be our terrain mesh. 4. 04 Import And Prepare Jeep: Now that we have this model finished, now we can import our Jeep model, and let's rig and animate our Jeep model using the RBD bullet solver. And first, let's import our Jeep model. And if I go into my folder, here's can see, I have already downloaded all of the assets that we need. And here we have the Ville Jeep. If I double click Here's CC we have this one, Ville Jeep USDC. And when you download this, you will only get this USDC and you do not have this material folder. And to actually extract the material from this USDC, we can open this USDC using the VNR because USDC is actually an A zip file, which means Winaar can open this. So if I right click and here we have the open with, let's open this with WinRar archiver. Let's open this, and here as you can see we have this SN file, which is an AUSTC and in here, we also have folder named zero. And in here, we have all of these material. So you can just click and drag this, and I'm going to I just click and drag in here and I rename this folder from zero to this material. And here we have all of these maps. Now let's import this Village USDC into our Houdini scene file. So let me open up my Houdini file, and here we are. And to import this, we have an node called USD Import. So if I add an A USD import node, here you can see, we have the USD file import. And let me import this onto this side because we are going to create many more nodes. So we need this space. And onto the USD file import, let me view this and onto the file, let's pick up our file. And I already have stored into this emrfle. Let's go into the Geo, and here we have all of our assets. Let's go into the Ville Geb and let's import this USDC and hit Accept. And here you can see our model has been imported. Let me enable back this view plane grid. And right now the size is too large. So let's scale this down. And I'm going to add an A transform node for that and let me view our transform and onto the uniform scale, let's scale this down to 0.1, and I think it is an A still very large scale. So maybe let's lower this down to even lower value. So zero point double 06 and press F. And if I were to middle mouse button, and here you can see, we have the size, and that is an A 1.8 meter by four meter, and I think that is an A good size, that is manageable size for our RBDcm. So let's keep it onto the 0.06. And now let's orient this Jeep as well. Right now, it is facing onto negative Z, and I'm going to rotate this onto the Y by 180 to actually face into this positive Z direction. And if I were to middle mouse button, here you can see now we have this packed USD file and we also have an A name and the path attribute. And let's visualize our name attribute. If I were to click on this one, let me find there. We have the group. Let's click on it, and in here, we can actually click on this gear icon, and we can select the attribute and let's view the name. And into the name, we only have this scene. So maybe let's change this to a path. Let's click on it, and we also get this one only scene file. And to actually access this name attribute, we actually need to unpack this USD file geometry and let me hide this group option. Let's go into the transform. Onto the USD import, I'm going to click on this unpacked node, and that will unpack this into regular packed primitive. So if I were to middle mouse button, hers can see now we still have the packed USD, but now we have 20 separate pieces, and we also have the name attribute. And we can check. Let's go into this one display group. And here you can see now we have access to all of the individual pieces of this Jeep model. And we are going to create the group because we need the access to its heel for the animation and the body. So let's start grouping first this body. And if we were to actually check the naming scheme of this model, if I click on it, and let me see if we are viewing the correct attribute. We want to view the name attribute, and here you can see we have this name attribute. And in here, we have this one, the front LH, which means the left hand side, that is the tire and wheel and we have the front tire and wheel. So all of the names starting with front underscore, we need to group them separately because these are our wheel for that. Let's add an A blast node. I'm going to disable this. In here, let's add an A blast node, and I'm going to connect this into the blast, I can add an A expression if our at name if that is equal to front FRO and D front and underscore, and I'm going to add an A star, which means that include everything that start with front underscore and all of the name that is above this. Let's click on it, and here you can see now we have our wheel has been deleted this front wheel, but we have these back wheels, and we also want to remove these wheels as well because we only need the body and we can add another expression, and first let me check the name. Pattern of these wheels. So let's click on it, and here you can see we have this one rare. So these are our rear tire as well as wheel. So let's remove all of these that start with rear underscore. So let me hide this again onto the blast node, and in here, we can add another space, and I'm going to call this one. Let's add another name attribute. So at name, if that is equal to our re underscore, let's add an A star. Let's add this. And now, s can see we have these back wheels gone as well. And we do need this back wheel, this spare wheel because that is an a part of the body. So let's keep it like that. And that is our body separated from V. And I'm going to create an A group in here. Let's add a group name, group node. Let's at this, and I'm going to name this one our body. That is our body group, and I'm going to just move it here. Maybe let's move it onto this side, and let's add another blast node, and this time we are going to extract our wheels. So let's add blast node and connect this, and we know that we have the front wheel and they start with this name front. So I'm going to just copy this. Path in here at this expression, and I'm going to just paste it, paste it in here, and that will just remove these wheels. But we want the opposite of that. So let's click on this lead non selected. So these are our front wheel and these will be our steering wheels. So I'm going to create an A group in here. Let's add an A group node, and let me connect this. And I'm going to call this one S wheel and that means that these are our steering wheels. And let's add duplicate this plus node, press and hold the old key and drag, and that will duplicate this plus node. And we just need to rename this ad name from front to rear. So let me remove this front expression, and let's type this one rare. And if we view this and that will add these pack wheels. And now we can merge both of these wheels together. So let's add an A merge node. And I'm going to merge both of these plus node, and here we have these wheels. And now let's create a group named wheels. And for that, let's add an a group node. And let's connect this and I'm going to call this one our wheels. These are our wheel group wheels. And now we can merge our body as well as wheels together because now we have grouped and extracted all of these different pieces that we are going to animate. Let's merge our body with our wheels, and now we have our original GPA. But now with some groups, if I were to middle mouse button, now we have three primter group, we have body, we have the steering wheel, and we have these back wheels. These all of these wheels. And now we can add an A RBD configured node to rig this chip. So let's add an RBD car rig node. So let's add this, and I'm going to connect this, let's connect this onto this RBD car rig node and view this. And in here, we have the wheels group, and we have created our group for the wheels. So let's click on it. Hers can see we have the wheels. Let's select. So now that we have selected all of our wheels, now we need to define the steering wheel and we also have the group for that, and in here, we have the S wheel. Let's click. And Here's can see now we have the steering wheel as well. And in here, we can configure this RBD car rig for our RBD bullet simulation. 5. 05 RBD Car Rig: Now let's animate this cheap model with using our RBD car rig and pullet solver. And in here, first, heres can C, we are using the Pac geometry. And if I were to middle mouse button heres can C, we have the packed USD primitives and to actually create the attribute as well as rig or this model, this RBD rig require the polygonal geometry, and for that, we need to unpack this. And in here, let's add an unpacked node, first. And I'm going to connect this and let me enable the parameter of the unpacked node. And if I were to middle mouse button, and here is can see now we have the polygonal piece of geometry, but now all of the groups are gone because we are unpacking and now we do not have the name attribute as well as the groups that we have created. And for that, let's go into the transfer attribute, and we want to transfer our name attribute. Let me select this. We also want to transfer all of our groups as well. For that, I'm going to type Star and that will just output all of our groups. If I were to middle mouse button and Hers can see we have our group three primitive groups. Now Hers can see we have the green, which means these are our steering wheels. We have this blue and that is for our suspension. Now that we have this visualization, which means that this RBD car is working fine. And if I were to middle mouse button onto the unpack and Heres can C, we do not have the UVs. And when you import the USD format, the UVs are called the ST zero. Here's Ken C, we have the ST zero, so that is the UVs and Heres ken C. Houdini is recognized them as UVs. And we actually need to rename this into UV to actually visualize. And for that, I'm going to add an A attribute, rename node, and after that, I'm going to add the attribute rename, and I want to rename the point attribute from ST zero to YUV. Let's add this. And Heres can C our view port has recognized the UV attribute. And if I were to middle mouse button Hes can C we have successfully renamed this ST zero attribute. So maybe let's remove all of the attribute that we do not need. Here as you can see, we have the primitive attribute. We have the USD path and all of these that we do not need. And for that, let's add an A attribute, let nod. And I'm going to click on this Plet non selected to get rid of all of the attribute, but we want to keep the name attribute. So let's add an NM, and we also want to keep the UV attribute. And we also want to sorry, we actually added the normal. We we do need the normals, but we do not have the name attribute. So so the name attribute is an a primitive attribute. So let's go in here and here's can see we have the name. And now if I were to middle mouse button, now we have the name, normal UVs and we have these three primitive group. Now that is good and optimized geometry in terms of attributes because we do not have all of these unnecessary attribute. Now onto the RBD car rig, we can add an A RBD bullet solver in here. So let's add the RPD bullet solver, and we can connect this geometry and constraint because that node will generate our constraint for us. It will also generate the proxy geometry for us as well. And we can go into the RBD bullet solver, let's visualize this, and we need the ground plan for the collision. And for the collision, if I go into the RBD bullet solver, we have some parameter. Let's go into the collision. And right now on the ground collision, we have the ground type set to none. We can change this to ground plane, and that will add an infinite ground plane, put in add default ground plane. But we need our own terrain mesh that we have created. And for that, let's use this as an height field, we want to add the height field collider, and let's find our out null that we have created. Previously for adding the collision, hers can see we have this height field. Okay. So we are going to use this height field for collision, and I'm going to enable the parameter of my RBD bullet solver onto the collision and onto the height field, let's click and trag this null in her, and now we have added this height field as an A collider. Let me view my RB. Bullet solver in here and to actually visualize this, let's go into the RBD bullet solver and onto the visualization, and let's enable this ground option. And right now, if I just click and enable this option, that will cause the Houdini to refresh the viewpot and Hearers can see now we are visualizing viewing our collision ground. And here you can see the orientation is not correct. Our Jeep is not in the correct location. And to actually move this, we can add an ARBD transform node in here, so that will take care of these orientation. I set this, and I'm going to connect this in between after the RBD caring. Fiber to view this, and here you can see we have this basic transform, but that is for this RBD rig that we going to adjust the position of our original higher geometry, constraint geometry, as well as the proxy geometry. So we do not need to create the additional these three transform for all of these different geometries. This RBD trans node will going to take care of all of this. And we just need to align this on this bullet solver. And I'm going to view the bullet solver. And first, let's rotate this onto the Y, and I'm going to rotate this onto the 90 degrees. Okay. And I want let's move this back as well, and onto the translation X. Let's move it back, and let's start this right about here. Maybe let's change this to minus six round this off to minus six. And here as you can see we have these wheels. They are penetrating the ground, and that is not good. So we are going to add an A offset into the Y just a little bit. So let's increase the offset and maybe let's lower this value to 0.1, and it's still not enough. Maybe, let's add an 0.14, and that is looking good to me. Okay, now we have this collision taking care of. Now, let's go into the RBD Bullet solver. Let's enable the playbr and click on this real time option to enable the real time playback, and let's view our simulation. And here as you can see our car is bouncing, but it's not moving. And let's adjust some of the attributes. Let's go into the RBD car gnode and in here, we can define the speed right now the speed is zero, and to actually get the car moving, we need to increase the speed. So let's start this with value of ten maybe. So let's play again, and here we should see that our car will going to move and heres can see. Sure enough, our car is moving. And here I have simulated this 100 frame to view the result. And if I were to go back, the viewpoard performance is not good. So maybe we need to create an flipbook to actually view the animation of this car. And for that, let's click on this flipbook option. Let's flip book this with new settings. And onto the size, let's enable the resolution. And what that will do, it will use the entire viewpod size as an A resolution. So let's go into the output, and that is right now, we have the frame range, which means it has the expression RFN which means we are going to create the flipbook for all of our 240 frame, but I only simulated the hundred frame, so let's maybe let's change this to only 100 and let's start generating our flipbook. Okay, flipbook is done. Let's view our simulation. And right now Hearers can see our speed is too fast. I don't want that fast animation. So maybe let's lower down the speed, and also the car feel rigid, which means we need to adjust the suspension attribute as well. So I'm going to just close this flipbook generation. Let me go back onto my very first frame. First, I'm going to decrease the speed. Let's change this to five. And let's go into the configure, and here we have the option for this suspension and all of the tire friction, all of them. And what I want, I would like to lower down the stiffness. So maybe let's change this to half value. The default value is 40, so let's half this to 20. And now let's create our flipbook of our hundred frame as well. So maybe because we have we have lowered down the speed of our car. We need to create an A. We need to simulate more frames to actually view the result because the speed is slow, and I'm going to create an flipbook with new setting, and this time, let's create an flipbook of 150 frame. Let's start this. Okay, flipbook is done. Let's review our simulation. And now hers can see that this suspension is working, and I think the speed is good as well. Let's adjust the animation right in here where we are crossing this waterline. I want the car to slip a bit because we have an mud in here and right now it is going just fine, but we want to add the slipperiness in here to actually create an animation of that this Jeep is going through mud and it is slipping. And for that, we can actually animate the friction. We have the friction attribute onto the wheels and if I were to lower down the friction, that will cause these wheels to actually slip onto the ground. Let's see how we can do that. I'm going to close this flipok window in here and if I were going into the RBD carrid and Hears can see we have this star bounces and we have this tr friction. If I were to lower this value down, let's slot this down to 0.1. And if I were to hit play and here you will see that our wheel is spinning and Hears can see, let me zoom in. Let me zoom in onto this wheel. Let's rewind and hit play. And here you can see our wheel is spinning, but it's not moving because the friction value is very low. So let's animate this value. I'm going to change the friction value to one, and to actually animate this, we cannot add the key frame onto the soap level RBD car g because we are in the dynamic simulation. And in the dynamic simulation, all of our geometry is going to be initialized onto the first frame, and after the first frame, all of the updates will not going to be updated into this bullet solver. And to actually animate our friction over time, we need to actually dive inside the RBD bullet solver, and in here, we can add an A geometry wrangle. Let's add an A geometry wrangle and let's connect this onto this pre solve. And in here, we can create adjust our friction attribute, and this emt angle will going to be executed on every frame, and that will going to any male. So let's add our friction attribute. So that is an A floating a point attribute. So let's add an A F, which means the float and the add sign, and we are going to add the name of the attribute, and let's set this onto give him an A slider, and for that, we are going to create an channel, and let's type this CHF which means the channel float. And now in here, we need to type the name of our slider. And I'm going to call this one friction. Let's at the semicolon, and let's click on this, create the spare parameter option to actually add the friction slider. And now we can animate this friction to actually animate this or this slipperiness over time. So by default, at the very first, I'm going to start the friction at one, which means the full friction and after the few frame, let me see which frame we want to actually adjust our friction. Let me simulate few frame. Let me stop this and here's can see I have simulated few frame, and we want to animate our friction right where we have these wheel into the muds. I think the wheels are in the mud at right here at the frame 75. So onto the 74, I'm going to add an a key to actually add an a key, press and hold the old key and click that will add an a key frame and here can see our parameter has been turned green. So let's go and at the frame number 75, and I'm going to lower down the friction value to 0.1, which means a very low friction value. So let's add another key, and I'm actually going to disable the dynamic simulation because I want to go into the few frames. So after I think the frame number 140, I want to keep the friction value of 0.1. So at the 140 frame, I'm going to add another key, which means that all of these between these frames, we have this friction value at 0.1. And after the 140 frame, I want to actually start increasing the friction. And I want to increase the friction, I think, at the frame number 163 maybe. Let's keep increase the friction value to one. And let's add an even and add an A key frame. So now, after the hundred and 40 frame, our tire slowly start to move and they will stop slipping and they actually start to move. At the hundred and 63 frame, we have the full friction and our car will going to be just fine after this frame. So let's review our animation. So let's hit rewind and I'm going to enable this dynamic simulation by clicking on the sprain icon again. Let's go back and let me zoom out. And this time, let's create the flipbook of our hundred and 68 frame. Let's add in 168, and let's start the flipbook. Okay, flipbook is done. Let's review our animation, and here we have the suspension working, and here as you can see now we have the slipperiness. And I think this slipperiness is working fine. You can adjust it to your own liking, but it looks fine to me. So I'm going to say that that is an A okay simulation. And first, I'm going to adjust the frame range. Right now we are using the 240 frame range. Let's increase this to 275. Let's increase this and let's case out our simulation onto our disk. And for that, let's add file cache node in here. Side this and we want to connect this last one. That is the simulation point. And we are not going to actually case out this geometry because that will be a very high cache onto our disk. So what we can do, we can only cash out our simulation points, and then we can transform our original geometry with this simulation point. And for that, I'm going to just add the simulation point in here on to the file cache, let me enable the parameter of it, and onto the base name, we have the expression. The first, we have the dolosine hip name. I like to just remove the dolosine hip name, and I want to use the dolosine OS, which means the operator name itself. And I'm going to call this one our Jeep SIM. So RBD G SIM. In here, we have the base folder where we want to actually store the cache, and I want to store the cache into my SIM folder. Let's go into the dollar sign. Hip file, and let's go into the SIM and hit Accept. I want all of the simulation to go into my SIM folder. And in here we are simulating the 275 frame, and that is correct. Let's click on this save to disk option to actually case out our whole animation. Okay, all done, the simulation has been done, and now if I were to visualize our cache and view, and heres can see we only have these points. So we only cashed out these points. They have all of the necessary attribute. If I were to middle mouse button, hers can see we have all of these VW as well as the orientation attribute, and we are going to use these points to actually animate this higher geometry that is coming from this RBD car ring. For that, we have an node called RBD car transform. So if I add an RBD car transform, and here as you can see, let's add this, and it requires the geometry, and we want to connect this transform geometry where we have actually oriented correctly. So that is our geometry and the constraint. These are constraint and the proxy geometry, and that is our proxy. And for the simulation points, we are going to use this cached animation. I'm going to just connect the output or this file cache onto the simulation point now if I were to visualize the RBD car transform, and Hears can see if I were to scrub my playbr and heres can see how this animation is now being applied onto this static geometry, and we are using these animation points, which is a very lightweight cache to actually animate our original Hiras car. And at the in here, we have the geometry that is hirasGeometry, fiber to add an a null. Okay. And here you can see that is our highs geometry, and we are going to use this for rendering. And for that, I'm going to rename this out his Jeep. And later on, we are going to reference this null for importing into Solaris for rendering. So that is our high ras piece of geometry for our GP. 6. 06 MPM Solver Overview: Let me walk you through the MPM solver if you haven't used before there, let me show you how you can set it up. I'm going to come in here and create an A Geometry node. Let's dive inside the geometry node, first we need the source. You can create any geometry for source of your emission. I'm going to add an A this geometry that side effects has provided the squab. Let's add this and we have our lovely squab geometry. Let me enable the parameter of this geometry and let's move this geometry up a bit. And for interesting motion, maybe also let's add some rotation as well. Now to create the MPM simulation, first, we need the MPM solver. Let's type there. Here we have the MPM solver, and like all of the solver, it requires the PM source. The middle pun is for the collider and the last one is for the container. First, we need to add the source, and by the way, you cannot add this like this, it won't work. We have an node called MPM source. If you type PM, let's add an PM source node. Let's add this and we can connect this in here, let's visualize this. Right now the MPM source is throwing an error because the MPM source require actually the container to set the resolution of our source geometry. First, let's create the MPM container. Going to add an MPM container node. Let's add this and the last one is the container. Now we can connect this into our MPM sources. Let's view the MPM solver, and here as you can see the PM source is still throwing an error if we enable the parameter, and here we can define the PM container. Let's click and drag this PM container onto the MPM container field, and now the error is gone and now we can see our geometry has been converted into these particles. The MPM simulation is basically an flip simulation. We have this particle and we have the volume. If you work with flip, it's more like flip simulation, and I think it is flip the extended version of the flip. Here onto the PM solver onto the solver type, we have some basic attributes. We can set the gravity and air drag wind velocity, and we also have the option for the surface tension if we are going to create an water simulation, you can enable the surface tension. Now if we hit play, let's see how the default behavior looks like, and here is can see right now that's how it looks like. We can go into the MPM source onto the MPM source. Here, we have the material preset. Right now we are using the snow preset and the behavior is set to checking key. We have lot of different presets we can use. Let's say if we want to create an A water simulation, we just need to click on this water and if we hit play, here you will see that our simulation will behave like water and here you can see. Now it looks as if we are simulating the water. And onto the MPM container, we can define the bounds because it is an A flip simulation. So we need the bounds and to actually visualize the container, we need to go into the MPM solver and onto the visualization, and we have the show container option on, but I cannot view this. Let's see why. Now I'm in the MPM container. I'm going to lower down the size of our container. Let's lower this down to three by three. And the reason we cannot see our domain are these or the container box, and that is because we are currently using the boundaries as an A open. If we were to click on this, that will use this option for all of the axes. We can click on this to closed, and now heres can see because we are using the closed bounds, now we can see the container bounds. So all of the simulation will going to be live inside of these bounds. We can increase the size of our bonding box. Let me move this up a bit onto the translation. Y, and let's play here you will see onto the bounds at these boundaries or this container box will act as an a collider. I can actually set this to delete, which means that if the particle leaves these bounds, they will simply going to get deleted. And here you will see here can see. Now, all the particle that try to leave the bound, it simply just get deleted. Let's keep it as closed, and we can actually set the container bound if we define the input geometry in here. For example, if I create an A box in here, maybe let's set this. And we can scale this box to our liking and we can actually use this box to set the bounds. Let me increase the size onto the X. And now, if I just connect this onto the domain geometry, now the PM container will use this geometry to set the domain. Now we can go into the PM solver node again, and here you will see we are using these same bounds. I can just click and drag to actually increase the bound because our squab head is cutting off, and I'm going to increase it a bit more and let's play. And that is our container. And we actually do have an preset for the PM solver to quickly set up our simulation. If we type MPM configure, let's add an PM configure node. Here you can see, we have the PM configure. Let's add this. And what the Houdini will do, it will add these basic nodes required for setting up the MPM simulation. We have the solver, we have the source, we have the coldr and we have the container all ready to go. Sweet. Now, we just need to. We don't need them just remove all of these nodes, and onto the PM source where it says, I can just remove this sphere and I can connect my own source, and I want to connect the squab in here. And let me enable my Vetool and let it play. Here you will see that we have this snow like preset, the default snow like preset and our squab is looking like we have an A snow. I can go into the MPM source tab and onto the material preset here as you can see, we have the snow option. I can change this to let's say water and now we have the liquid behavior. Let's see. Sure enough, we have water like simulation and we can add another type of simulation in here, for example, we can mix multiple material into this simulation. I'm going to add an A, let's say Rubber to in here. Let's add the Rubber geometry. And let me template this. Let's enable the parameter, and let's move this geometry a bit up. I'm going to move this up. Okay. I'm going to add another PM source node or we can just duplicate this PM source. Just press and hold the old key and drag and we can effectively duplicate the source node. Let's connect this in here and to actually add them both together, we can add an A merge node. Let's merge them both of these sources together. Let's add this. And the first one, I'm going to convert this rubber away into water. So let's go into the MPM source, and right now it is set to water and liquid, it is good. And onto this squab, I'm going to change this into sand. So let's go into the material preset, and in here, I'm going to change this to sand. And we have the sandy behavior. Let's see the result. And here you will see uptp we have water and down we have the sand and we are going to mix both of these materials together. And here you will notice that this simulation is getting slow because when we are working with multiple material, the simulation will get slow. I'm going to stop this and to actually create an A visualization a better. I'm going to add an A color onto our particles. First, let me template our rubber toy. After the MPM source node, I'm going to add an A color node. Let's add this. And because that is a sand, let's create an sandy looking color. Maybe let's change the two more lighter brownish color. That is our sand. And same thing. Let's add a color node onto our rubber toy as well. In here, let's set this to a lighter blue color. Let me change this a saturation value, something like that. Now we can differentiate in both of them. Now let's play again. And here as you can see, we have the sand on down and up we have the water. Maybe we can adjust the bounds of our MPM container. I'm going to use the size that we have onto the domain. I'm going to close the boundaries. So let's enable this and all boundaries, I want this to be closed in a closed box. And let's move this a bit up. Maybe let's move this five unit up. Let's try this again. Okay? The bound is still too big for to actually create the collision onto the water. Let's go into the container, and let's lower down the overall size. I'm going to lower this down to maybe five in both of these axes. And now let's move this down. I'm going to move this down to maybe unit of two or maybe three. Let's play again. Okay. So here you can clearly see that we have these two simulation working together and you can actually control the resolution of your simulation. Right now, the simulation is very low as to actually create the higher simulation to add more points set the resolution onto the MPM container node. Let's enable the parameter of the MPM container, and up here, we have the particle separation. So if we lower down this particle separation value down, let's change this to 0.01. And here you can see, now we have a lot more particles. Now we are creating a more highs simulation. And you can keep lowering this value down to create high rise simulation. And in here to actually add the convert this into mesh. For example, we have the sand and we actually do not need to convert the sand into mesh because we are going because you will going to use these points to render the sand. So we do not need the mesh onto sand, but we do need the mesh onto the water. So after the PM solver, we need to separate both of these sources. And actually, the sources name is controlled by the actual this node name PM source. Let me show you if you go into the PM solver and middle mouse button here, you will see that we have the source name attribute. And here you can see it is string, and we have these two unique name. And we can check if we go into the PM solver geometry spreadsheet, and that is an A point attribute. Let me find the name attribute. Here we have the source name. The first one is set to PM source and because we are using this PM source and this 1:00 P.M. Source one. So let's rename them properly. I'm going to rename this to sand and the PM source one, let's change this to water. And we actually need to hers can see onto the source then we have all of these changes reflected. Now let's go back onto the sin view again, zoom out, and let's play again to simulate a few frames. Let me stop this in here. We actually do not need to simulate this because we know how this simulation looks like. Now we just need to separate these sources. Let me stop this because we are using an AI very high rise simulation. That is why the simulation was taking too long to simulate so I just stop this at the frame number six. And after that, to actually separate the sources, we can add an blast node in here at the end of the PM solver. Let's add the blast node and enable the parameter onto the group, we can say change these two points. Let's inhere type the attribute name. And if we middle mouse button, we have the source underscore name. So in here, let's type at source name. And if that is equal to water because that is an string, we need to type the name, water, and the colon and now here you can see the geometry has been deleted. We can just click on this delete, non selected to actually invert the selection, and now we can rename this to our water geometry. Sorry, that is not water geometry, but that is our water particles. I can duplicate this node again and I'm going to uncheck this delete non selected node, and this side, we have the sand. Now we have both of these sources separated onto the Water node to actually convert this particle into mesh, we do have an node called PM surface node. Let's type an PM surface. Here you can see, we have the PM surface. Let's add this and we need to connect this onto the very first input, which is the MPM particle. Let's view the MPM surface node, and here's can see we have this mesh generated, and right now it is an A VTB mesh. Here's can see, we are creating the surface VDB that is not an polygonal geometry, but we can go into the output type and change this to polygon mesh, and now we have the polygonal mesh, and we have some option. Let's go into the surface tab. And if we enable the filtering option, here we can dilate or smooth. So maybe let's enable the smooth option, and I'm going to just increase the smoothness value to actually create an a smooth mesh. And maybe let's change this to an smooth shading. So let's click on it here and we have this option, smooth shaded. Let's add this. Okay, now we have the smoothness. And that's how you can convert this into an A mesh. So that's the basic of MPM solver so in the next lesson, let's learn more about the MPM solver, and let's continue our project and create the MUD simulation in the next lesson. 7. 07 MPM Source Mud And Water: Now let's create the MPM simulation, and first, we need to create these sources. Let me zoom out and in here, let's go back where we have the terrain node, let me view my this geometry node out terrain. Now, let's extract the water line that we have created. If you remember, we have the mask in here. If I were to let me say height field mask shrink. That means oo. Here's can see, we have the mask, and we will going to be using this mask to create the waterline. So let's go into the terrain and press F to zoom in. And if I were to middle mouse button, we should see the mask here we have the mask and we can actually visualize this. We need to hower over the node, click on this eye button and click on this mask to actually visualize. And here is can see, we have the mask. And when we converted this by using the height field convert node, this node, it will actually transfer all of the masks as well, which is good. I'm going to first let me height the visualization of the mask node. So let's disable the mask option. And down here, we can add the Blast node, and we can say remove if at mask I sop from mask red value. Let's say if at mask dot or if that is equal to one. Let's add this, and we need to change these two points. And here you can see we have this water line gone, and we need the invert selection. So let's click on this let non selected option to actually invert the selection. Here we have our water line extracted. And if we zoom in, you can see we have some of these unconnected points. So they will create some problem down the line. Let's add an A clean node to actually remove all of the points that are actually disconnected. Let's click on this and the clean node will going to create an A clean geometry, and it will remove all of the unused points. Now we need to add the thickness because right now it is an A flat surface geometry. For that, let's add an poly extrude node, and I'm going to add the distance value maybe let's add the value of 0.1, and I think that value is enough. And down here we do not have the output back. So let's click on this output back to actually create solid piece of geometry. And now, it's just a matter of creating the MPM source node. And for that, first, I'm going to create an A MPM configure because that will set all of the basics barebone node that we actually need. Let's add MPM configure and we have all of these basic nodes. I'm going to remove all of them the MPM source sphere as well as the MPM collider. We have the default box. So let's remove both of them, and let me go back and we are actually at the frame number 37, so let's hit Rw. We must be at the frame number. Very first frame. Let's go into the MPM source. I'm going to connect this in here after the Polyxtrude and onto the MPM source. I'm going to rename this to water. So let's type water onto the MPM source and onto the material preset. Let's change this to water and the liquid preset and this liquid behavior. And we are fine with that. We can actually set the resolution onto this MPM container, and we will adjust the resolution later. But now let's create the actual mud because now we have the water line and to maybe actually visualize this better, maybe let's add an egg. Or node in hair to actually color our particle to bluish looking. So let's go into the color node, and let's change the color to a light blue color, and I think that color is looking fine. And now let's create the mud. And for that, I'm going to make the selection because I want the mud onto this edge. So let's isolate the part which we want to convert this into mud. And for that, I'm going to add an A attribute paint node to actually paint the mask. So let's add this, view the attribute paint mask and hover over to the viewpot and press Enter. Now we can visualize this mask because we already have the mask attribute present. So let's go into there and the attribute set to mask. Maybe we can actually remove the previously created mask. Let's inhere add an attribute let node, and let's remove all of the attributes that we actually do not need. Let's click let no selected to remove all of the attributes. Do not need any attributes in here. So let's go into the attribute paint, press Enter. Now we have an A perfectly clean mask geometry. Now, let's increase the brush, and we have some shortcut in here to actually increase the brush. We have the control shift, and we need to press and hold the left mouse button of our mouse and drag, press control shift and left mouse button and drag to actually increase the size of our brush. And I'm going to increase the brush size and make a selection onto these edges. Maybe let's lower this brush size a bit down, and let's make a selection. I'm going to select this edge boot very roughly, and let's make an selection on this in here as well. Let's keep selecting. Let's select this part. And let's also maybe add this part as well. And let's add this piece of geometry. And let's add this one in here as well to maybe let's increase this pot a bit bigger. Let's add this. Okay. Now that we have the mask created, let's extract this. For that, let's add an blast node. So let's add the blast. And by the way, right now, we have the mask onto our point level. If I were to visualize, here you can see our mask is on the point level. Let's promote this onto primitive level and that way we do not have all of the unused points. So after the attribute paint node, we can add the attribute promote node. And let's promote the mask attribute on this mask into an ape primitive attribute. And that way, we do not have to worry about all of the unused points now because it's a primitive attribute, so all primitive that are red will going to be extracted cleanly. So after the attribute remote, let's go into the Blast node, and now we should be able to select. Let's change this to primitive and let's click on it. And right now I cannot see the attribute, but that's fine. I can say at mask if that is equal to one, which means the red value. And here we have it. Et's click on this, delete non selected option. And right now heres can see we have some of the missing patches. So let's go back onto the attribute paint node again. And if we zoom in, Hers can see, we can just click where we have Let me view the blast node, and here we have another. Let's click on it. Let's view this. Okay, we have some of the hole there as well. So let click. Let's click and select. Let's select this so that we do not have any holes. Okay. I think now that it is looking fine. We do not have any holes. Now let's add some thickness onto this geometry because right now it is a thin surface. So let's add an extrude node. And let's connect this onto polyextrude and let's add the thickness value of 0.1. Let's also enable the output back option to actually create this thicker geometry. Or maybe let's increase the distance value a bit higher. 0.2, now we have this and that will allow us to add more points onto the source because we are using bigger thickness value. And after that, let's convert this into VTB because right now it is looking more rough hers can see. The geometry is not organic looking to create the organic looking geometry. Let's convert this our polygonal geometry into VDB. For that, let me adjust all of the node graph and let's move them down. So after the polyetrude, let's convert this into VTB. So let's add VDB from polygon node and connect this and I'm going to set the resolution to an A 0.02 to create a more high resolution variant of our BDB. Let me zoom out, and at the end, let's see, we have this our geometry, and if I were to template this Heskonc, we have this geometry at the end. So maybe let's clip this part of geometry so that we do not have particles falling down because we are not actually going to see this geometry anyway. So let's maybe add an A clip node in here. So after the polyetrude, let's add an clip node. And let's connect this and maybe let's clip this onto Z direction. Right now we are using the X, so let's zero it out. Let's use the minus one as our axis. And here as you can see, we are clipping our geometry, and let's adjust the distance value, and we actually need to set this one to Maybe let's change this to minus seven. Okay, so now we are just clipping just a little bit of our geometry. And we can also click on this fill polygon as well because right now, if I were to template this here as you can see, it is creating this hollow geometry. So let's add an A fill polygon, and that will take care of this hole. Now, we can convert this into VDB and maybe let's introduce some organic noise onto this VDB as well. Right now, it is perfectly flat. So let's add volume noise in here because we are working with volume. So let's add a volume noise SDF because we have the SDF geometry. Let's add this. Let's connect this and view the volume noise node. And we have the zero centered, and that is correct. So let's increase the amplitude to a higher value. Maybe let's change this to 0.5 and let's see the result. Okay. Now here you can see, we have our geometry deformed quite a lot. And it also looks organic. So let's keep it like that. And first, let's move this source up because when we are going to simulate, if I were to view this or maybe template this terrain, here you can see we have our source going down, going below collider mesh, and that will create some problems. So let's move this a bit up. And that's at the transform after that, let's move this onto the Y axis onto the Y. Let's maybe move this one unit up and right now we are above we are rising above our ground, and that is fine because we are going to use the simulation or this MPM Solver, dynamic simulation to dynamically fall down this mud and settle down onto our geometry because that will create the natural looking this mud. So after the transform node, we can add an A MPM source node. And for that, I'm going to just duplicate this MPM source. Let's click on it, press and hold the key and drag. Let's click in here and we are going to call this one mud. Let's type d, and let's view the result. Okay. Now we have these mud particles added. Maybe let's add a color in here to actually visualize this as an A mud. So after that, let's add an A color node, and I'm going to change this to a brownish color, dark, brownish color. Let's desaturate this. Okay. That is looking fine. Let me move all of these node down. Maybe let's move this color node up. And now we just merge both of these sources. So let's add merge node in here and merge this with that. And onto the MPM collider, let's add this terrain geometry as a collider. So first, here, as you can see onto the train, we do not have an A thickness. So let's add the thickness onto our train geometry, and for that, I'm going to add the extrude volume node. Let's at the extrude volume node in here. Let's pick up wire and connect this at the end. Maybe let's move this up. Let's view the result of our extrude volume and heres can see this will add the thickness onto this train geometry. Let me enable the parameter of it, and right now we are using the depth of minus one. And maybe that depth is a little too high, so maybe let's lower this value down to 0.2 maybe. Okay. Now we have this enough thickness. We do not need that s -0.2 value is looking fine. So after that, we just need to connect this onto this MPM collider. Let me move this node a bit up and let's connect this onto our MPM collider node. Let's view our MPM collider node to see the collision mesh generated. Here we have the VTB mesh as a collider. Let's go into the MPM collider, and here we have the grade VTB from polygon option. That is correct because we are inputting the polygonal mesh, and we can actually overwrite the boxel size as well. Let's enable this and maybe let's lower this value down because right now, this SDF representation is very coarse. So maybe let's give some resolution to add detail. Let's add the value to 0.07 and I think that is good looking collision mesh. We do not need to create more high collision SDF more than that. That will work enough. Now, let's go back and let's view our MPM Solver node. And here we have it. And I cannot see water. Let me see why is there. We have the water node added. We also have the emmert. Why I cannot see the water line? Maybe let's go into the solvent node and let's simulate this, so it will update. Okay. I still cannot see it. So let me stop this in here and heros can see. First, we need to adjust this behavior as well because onto the mud, right now it is behaving like water. So let's go into the mud node because we are using the water preset. So let's change this to soil because that is an soil, and we do need the chunky behavior. Okay, that is fine. Let's hit play again, and here you can see now we are settling down this mud geometry, and now it will look organic because we are dynamically settling down this mud geometry, and I think now it has settled down, but I cannot see my water. It's going to the water node in here. We have the container correct preset water, and that is correct, too. So then why I cannot see it. Maybe let's adjust the container. So we have the size ten by ten. If I were to close this, that's at the closed boundaries, and let's see, okay, our container box is fine, too. So I think that is because of the ground plane. So maybe let's go into the MPM Solver, and onto the collision tab, Harris can see we have the ground plan, and we actually do not need the ground plan because we do have this rain mesh. So let's disable this, and now Hears can see I can see my water because the ground plan was actually removing this our waterline. And right now, our simulation is cutting off. Hers can see. So maybe we need to adjust the bounds. Or maybe let's go into our MPM container. Let me zoom in. And for now, let's uncheck this closed boundary, and that will actually disable these bounds. And now we have all of our geometry back. So let's simulate this few frame to actually settle down our water as well as this M geometry. Correctly. So let's simulate this few frame. Let's settle it down. And maybe I think at the frame number 30. And right now here as you can see we have some of the particles escaping and we also have the Mud escaping in here as well. So maybe we do need to adjust our bounds. And for that, I'm going to add an A box node in here and I'm going to use this box as by bound. So let's select this and press Enter. And I'm going to increase this excise. And also, let's increase this excise on the axis as well. Let's let me increase this size. Let's increase the Z size onto negative size as well and move this up. And also maybe let's increase this down. Let's rewind. Now we can use this as an A container, and now we can go into the MPM container and say, please close all of our boundaries. And now the water as well as this mud won't go beyond these bounds. Let's hit play again and now let's settle this down. Here you can see this simulation is now working fine. So let's simulate this few frame until we have this settle down version of our simulation. Let's keep simulating this. I think the frame number 38 is fine. Let me enable my camera. YouTol maybe let's play around with our resolution as well onto our MPM container. And right now we are using very low simulation, and as you can see, I can still see that these particles are leaving the area. Let me go back and let's go into the box and press Enter. Let's adjust the size. Okay. I think now that's fine. Let's go back our view tool and onto the MPM container. Let's lower down the particle separation to actually create a little bit more high version of our simulation. So maybe let's start this 20.01 for now, and let's see the result. And let's see. Okay, here we have, we have a bit higher resolution, but keep in mind that 0.01 is still a very low value, but I think we can work with that. So let me simulate few frame, and let's settle down all this mud. 8. 08 MPM Initial State: Now let's create the initial state of this mud geometry, and here I have simulated few frame. And here as you can see we have this water is flashing with the mud because we are actually falling down the mud down here. And actually, to create the initial state of this mud, we actually do not need to simulate this water as well. So let's hit rewind. And what I'm going to do, I'm going to just not import the water geometry for now. So onto the merged node, I'm going to just delete this water line and onto the MPM Solver. Now we are only just simulating the Md. So let's simulate this and let's settle down these particles onto these grounds. Okay, I have simulated a few frames, and now I think this mud has been settled down, and now we would like to create the initial state because we want the simulation or this mud to be initially start like that and to actually create the initial state. After the MPM Solver, let's add an file cache node in here, and I'm going to connect this onto the file cache. And here you can see we have these mud particles only and that is good. I'm going to rename this to our initial state. And onto the file cache, here we have some of the option based name. We have the hip name and the OS. I like to just remove the hip name. I'm only going to just keep the dollar sign OS expression, and we are going to simulate this only N. Sorry, we are going to write out this cache only this current frame. So onto the evaluate, let's change this to single frame, and that will use only the current frame that we are on and we actually do not need this time dependent cache option because it is an A steel frame. So let's disable the time dependent option. Now we are ready to save out our initial state. Here we can define the base folder, and right now we are storing this onto the geo location. And I think the geolocation is good or maybe we can change this onto our SIM folder. Let's go into our dollar sign job, and here we have the SIM. Let's cept let's save to disk option in here to save the cache. Okay, now we have save out the cache. Now, let's remove this from here, and we need to let's go back onto our where we have this MPM source node. What that node will do, let me press escape. Let's rewind onto the very first frame because we were at the frame number 24. What this node will does, it will just create some of the attributes that this node or this MPM Solver node needs to simulate. So what we can do, we can actually transfer the source attribute onto this initial state. So we can add an attribute transfer node in here, and I'm going to just transfer the attributes from this mud source onto my initial state. So let's go into the attribute transfer. Let's enable all of the attribute. So if nothing is defined, which means all of the attributes will going to be transferred. So let's view the attribute transfer node, and if we were to middle mouse but and here you can see we have all of the attributes present in here. Let me view the mud. And here we have the source name and source ID. Let's see. Okay, we do have some, I think, additional attribute. We have the JP and JE. Let's see if they are present in here. Okay, so they are not present in there. So what we can do after the initial state, I can add the attribute delete node, and I'm going to just remove all of the attribute by clicking on this delete non selected. So where we have the initial state, we are stripping off all of the attribute. So if I middle mouse button, we have no attribute. Now we can use the attribute transfer to bring back all of our attribute. So after the attribute transfer, here can see we have our attribute bags, and we can connect the color node now in here, and now that will be our initial state. So let's connect this color node, and now we can view our MPM simulation. Now here can see we have our initial state and we have our water ready to be simulated. And now we only need to bring our Jeep geometry, our Jeep collider, and we are ready to simulate this mud simulation. So let's bring our Jeep in here in the next lesson. 9. 09 Repairing Collision Geometry: Now let's bring in our Jeep model as an a collider. Because right now we have the mud, we have the water, but we do not have our Jeep as a collider. Let's go back where we have animated our Jeep and we have animated in here. We have the RBD Jeep simulation. We have this out high as Jeep model. Let me find where it is. We are looking at like that. Here we have it. Let's bring it onto this collider as well, where we have this collision geometry. Let me move this onto this side that is our collision geometry. I'm going to just duplicate this MPM collider node, and I'm going to add an merged node in here as well because we are going to use both of them as an a collider or this train geometry, as well as this Jeep model. And right now, we do not have Jeep model in here, so let's connect this. So to bring this geometry or this out high as geometry, what I would like to do, I would like to add an A object merge node in here. So at the end in here, I'm going to add an A object merge, and that way we can avoid any large of these wires, and we can keep this network graph clean. So onto the object merge, we have the option to import our object. So let me zoom in and let's drag this null in here, or out highers null. So let's click and drag. And now we should see our animated our geometry in here. Okay? And here as you can see, we have let me view this. Okay. I think let's disable this because when we are going to connect this, it will actually going to animate. So dynam simulation disable let's see, and let's scrub this. Okay. I'm going to connect this into the PM collider. And let's hit rewind at the very first frame and let's view our collision geometry. And heres can see how this MPM collider has been converted into SDF volume because we will be going to use the SDF for the collision. And right now the resolution is not very good. So let's go into the MPM collider and we can lower down the axel size. So let's lower this down to value on FA 0.01 and hers can see we have a much better representation of our collision geometry. But it's not perfect. Hers can see. We have all of these holes if we were to zoom in and here is can see. We have nothing in here and we have nothing in here. This happen when we have the bad geometry, so VDB does not know how to actually interpate this, and we need to repair this collision mesh for this SDF to work properly. Because when we are going to simulate this, our water and as well as mud will going to move through these holes. As you can see, we have these holes, and we will have an problematic simulation. So let's fix this collision geometry first. Onto the collided type right now is set to static, but we have the animation to actually bring the animation. Let's change this to animated git because we have the animation present in here. So let's see if the animation has been brought it. Okay. That is working fine. We have our animation, so let's hit rewind. Let's uncheck the move it to centroid. Let's see. Okay. Let's keep disable this move it to centroid. That will create some problem. So now let's repair this mesh. Let's go back where we have our highs geometry. Here we have our out his geometry. To actually view this, let's unpack this first. So what I would like to do, I'm going to add time shift node in here and let's connect this into the time shift because this animation is because it's an animated geometry, and we want an static geometry. We do not want the animation for repairing our model. So let's go into the time shift node and onto the frame, let's delete the channel. And now we are at the frame number one. Now we should see our static frame. Okay, that is fine. That is good. Now, let's start to see what's the problem. First, we need to add an unpacked node in here because right now we are using the pack geometry and to actually access the polygons, we need to unpack this. Let's add an unpacked node, and let's view. And here you can see, we have some of the thin surfaces. And maybe if I were to visualize this, if I'm going to, let's see, we have tin pack faces, polygon, and here's can see. Here on to the glass, here is can see, that is an a thin piece of geometry. So whenever we have this thin piece of geometry, it will create the problem in the VDB mesh in creating the SDF mesh. So we need to add the thickness in here. Just a little bit of thickness, we're going to fix the problem. So first, I'm going to add fuse node in here to actually fuse out all of the points that maybe not connected. So after the unpacked node, let's add a fuse node, and I'm going to increase the SNAP value to a higher value. So we'll change this to 0.01, and here as you can see, we have this this visualization weird visualization going on, but that's fine because we are going to convert this into surface VDB, we do not need to care about this shading artifact. 0.01 value is fine. After that, to add the thickness, let's add a polyetrude node, and I'm going to connect this in here and onto the polygon, we only need the little bit of extrusion, let's add just a slight bit of distance. The value of 0.1 maybe too high. So let's lower this down to maybe an A value of 0.01. Okay. And I still see this weird visualization, and I think that is coming from because we are using the connected component as an A extrusion method. So let's choose the individual elements, and here you can see, because we are now using the individual elements as an extrusion. Now this extrusion is working fine. And now if we were to create the SDF, and we also need to enable the output back because I can still see that we do not have the thickness to actually add the thickness, we need to enable the output back. And now we have the thickness, and I think that will create an correct mesh, and we can check if I were to add an A VDB from polygon node. Let's add this and let's connect this after the VDB from polygon. And I'm going to lower down the Waxel size to 0.01 to actually view, and now hers can see. We have our SDF volume representation, and we do not have any holes. So that will be our correct SDF collider. So now let's import this. First, we need to actually animate this repaired mesh because right now, Hers can see we do not have any animation. Because we are using the Tshift node. So let's use the RBD car transform node again to actually transform this geometry as well. We are going to render this out highs geometry where we have this null. So we are going to use this as an render, but this one will going to be only act as an a collider. So we also need to animate this as well. To actually make this RBD car transform work, we need some attribute because this RBD car transform load, look for the attribute to actually match these points. Here as you can see, we have these animated points to actually match these points onto the pieces of geometry, the original pieces of geometry to move them correctly. And for that, we need the attribute. So after the unpack, let's go in here and we were to transfer the name attribute in here. Let's click on this select option and let's transfer name attribute. We need this attribute. Let's go into the unpack and here we have this where we have our original polygonal geometry. Let me disable the point visualizer and middle mouse button. And now here as you can see, we have the name, and now we have two name attribute. We have one name on the primitive and we also have the name onto the point level. And we actually do not need this primitive name attribute, so maybe let's add an attribute, let node, and let's remove this primitive name attribute. Let's select this and view this and we do not have the name on our primitive. That is fine. And now we need to pack our geometry. When we have fixed that, we have the fuse node, and we have the poly extrude node. Now we just need to pack our geometry back because we need the pack geometry for transformation. So let's pack this. And if we were to middle mouse button, here you can see we have one pack geometry, and we need the individual pack geometry. Remember, we have these wheels separate because we want these wheels to spin. So we should have five unique name because we have four of these wheels and one for the body. And we need to actually go into the pack node, and inhere, we need to enable the name attribute to use the name. It will look for the name attribute and pack the geometry. And here as you can see it is throwing an error because it cannot find the name attribute. And if we were to go into the Polyxtrude and middle mouse button, here you can see, we have the name attribute, but that is onto our point level, and the pack node require the name attribute on the primitive level to actually brack out this geometry. So let's promote this. So let's add an attribute. Promote node in here, and we are going to promote this name attribute from point to primitive. And let's uncheck this slide original because we do need the name on the point level as well. Because later on when we are going to use the RBD car transform, this node will require the name attribute onto the point level to actually work. So here we have the name onto the primitive, let's add a pack node. So now the error is gone. And if I were to middle mouse button, now you can see we have five packed fragments. But we do not have the name attribute, and we also lost our access to groups. So let's go into the pack node, and let's transfer the name attribute, and let's transfer all of the groups. Let's add an star in here, which means we want to transfer all of the groups. So if we were to middle moose button, and here is can see we have our name attribute pack, and we have the primitive group pack. We have steering wheel, wheel and body. So that is ready to be animated using the RBD car transform load. So what I would like to do, I'm going to just duplicate this node in her and where we were using the original geometry from this RBD transform, we are going to use this repaired geometry. So after that, I'm going to add an A null inhere and I'm going to call this one repaired Jeep. Okay. And to actually avoid these messy looking wire, what I would like to do, I'm going to add another object merge node in here, and onto the object merge, I'm going to just click this repair jeep onto this object. And that way, we have the access on hair as well. So which means I can just connect this into my geometry, and all of these will remain the same. We have constraints SM proxy SM and the animation point, all of these will be same. So let's go into the RBD car transform and let's view the result. And here is can see we have our animation back. Now we have this repaired mesh, which means I can add an null at the end, and I'm going to call this one for our collider jeep. Let's type this one collider Jeep, and let's go back where we have our object merge. This one, where we are using the high ras Jeep, we just need to replace the null with this repaired one. Let me go back. Go back and let me find this one. Okay, here we have our collider, so let's click and drag this in here. And now it should work fine. So we can check. Let's go back. Here we have collider, we can view the MPM collider and let's see how our collision mesh is looking. Okay. Now the collision mesh is looking fine. We can scrub to actually confirm. Okay, here can see. We have our collider working as we want. So let's go back. Now we have our collider fix. Maybe let's zoom out and let's organize this graph. And I'm going to select all of these nodes, and I'm going to create a network box around it. I'm also going to type this in here that that is our RBD curing. So for that, I'm going to create an sticky node in here. I'm going to just increase the size. And let's call this one RBD RBD curing and we can right click on it, and we can say hide the background. But first, I'm going to just increase the size of this font. So let's lower this sticky node size. Let's place it in here and I'm going to just click on this hide background to hide the background. And now we can just click and drag and place it. Okay, here we have our RBD car eg nicely organized. Now, let's view this with our collider. So let me enable my simulation bag, and I'm going to just template this collision box. Let's go into the MPM solver, and here can see we have our car back. And if we take a look, because our car is actually far away from this collision source, we can actually save ourselves some of the simulation frame by actually adding the animation offset onto the Jeep because let's say if we were to simulate this right now, if I were to hit play, what will happen? Let me see if we were to hit play, our car will going to be move down, it will settle down, and then it will start to move forward, and that will be our waste of calculation time. So let me stop this and let's see I think we have some of the weird problems going on with our wheels. So maybe let's go into the MPM collider and let's click on this one, move Pivot to centroid to let's see if that fix there. Okay, still did not fix this. Let me see why it is happening. Okay, I think the error is coming from this RBD car transform. So if I were to enable the parameter where we have the RBD car transform load. Hers can see we have the option realign wheels. So let's uncheck this and that should fix the problem because it was realigning the wheel and the alignment was not correct. So now the animation is looking fine, which means we need to actually uncheck this realign wheel in ha as well because it will I think going to create problem on our original highs geometry as well. So if I were to view my his geometry, that is looking fine. So make sure go into the car transform and uncheck this realign wheel option. So let's go back and check our simulation collider. Okay, here we are at the MPM collider. Okay. So what we can do, we can add the offset in here where this car going to collide with our mud. So let me see at which frame we are going to collide. So on to this one color node, I'm going to just template this geometry, and I think it's going to be attaching right at the frame number 52. At the frame number 52, we want to start animating. We want to start the simulation from 52 of this animation of this chip. So onto the object merge, I'm going to add an A offset. So for that, let's add an timeshift node in here. Let's add this. And in here, we have the Dloine F expression. So we can say DloineF, please add 52 offset. How which mean if we were to go back at the very first frame, the 52 frame will going to be actually I first frame for this cheap. So now we can properly create our MPM collider, and it will convert this into SDF geometry and we can go into our MPM solvnt node and let's view. Okay. And now here you can see when you start simulating, we are not going to wait for our car of this cheap to actually arrive at the simulation point because we have added the offset at the very first frame, and so we are not wasting any of our time. So maybe let's also optimize this simulation by actually not simulating all of this water as well as this whole mud particles. Let's isolate the particles where we only have the interaction going on. So for that, I'm going to create another box in here. So I'm going to just duplicate this box, and for this one, I'm going to, let's say, visualize and I'm going to just not simulate this where we do not have the interaction going on. So let's reduce the size of our domain, and I'm going to increase this size. Let's view our MPM solver, and I'm going to just template my this box geometry, and I'm going to just increase size because we have this Jeep going forward, and let's visualize our Jeep model as well by setting the display flag in here. Let me scale this down, okay? If we were to view, let's see that we are only adding the Jeep where we have the Jeep. Okay? Maybe we can lower this domain size even down, okay. I think that is looking fine. Let's see if that is cutting anywhere and I think it's not. It's working fine. So let's rewind at the very first frame. And now let's use this as an A our domain. Let's go into the MPM solvent node, and this will recalculate because now we are only utilizing less of the simulation. And here you can see we have all of our particles outside of these bound are now cut off. So onto the MPM container, let's check that closed on. Okay, so that is closed. So let's only simulate this area where we have the actual interaction going on. And that way, our simulation will be way faster and we are not going to be wasting our time. So after the MPM solver, let's add an A file cache node in here to actually cash out our simulation. So let's add an file cache node, and I'm going to call this 1:00 P.M. Sim. And onto our file cache node, I'm going to just remove the dollar sign hip name, and I'm going to store this into my doll assign job to my SIM folder, head accept, and that will be our simulation. We need the simulation, 275 frame, that is good. So let's go back. And before we actually write out our caches, let's remove all of the unnecessary attributes that we have present. If we were to middle mouse button. Here's can see we have all of these attributes that we actually do not going to need let's remove them and we will going to be saving ourselves a lot of disk space onto our cache. So let's remove these that we do not need. For that, I'm going to add an A attribute let node in here. Let's connect this let's enable the parameter of the attribute let node, and let's click on this let non selected, and that will remove all of the attribute. So into the point attribute, let's type the name of the attribute that we actually want to preserve. So in here, we want to preserve the P scale because we need the P scale for creating the mesh. So P scale is necessary attribute, and we also require our source name attribute to actually separate our mud from water because we are going to use the separate VDB mesh for both of these. So let's add the source name, and maybe let's transfer our velocity as well because we are going to be using the motion blur, so we need the velocity attribute for motion blur. So let's add on these three point attribute, and now we are ready to cash out our simulation. So let's click Save to disk and write out your simulation. And before I actually write out all of my caches, there is one last thing that I'm actually missing, and that is if we go into this collider jeep, on onto the MPM collider here where we are creating this one, this animated this jeep here, you can see we have the option for stickiness. So that will adjust the stickiness of collide this material stickiness with the collider because I want the mud to stick with these wheels. So I do need to adjust the stickiness. So onto the stickiness, let's adjust the value of stickiness to higher value. So maybe let's change the to 20 and that way, we will get the effect that when our collider or these wheels pass through the mud, the mud will going to actually be sticking onto the wheel. So make sure to adjust this stickiness. And with that, we are ready to write out our caches. So let's go into the MPM sim and write out your caches. 10. 10 Meshing MPM Simulation: Okay, simulation is done, and we have written out all of our caches. Now let's start meshing our simulation. And onto the file cache, we have our written out cache. And first, we need to split our water and Mud because right now we have both inside of this one single file cache. So let's add an split node in here, let's split them both of our simulations, our water, as well as the Mud. So let's add the split node. And I'm going to type this one at source name. Let me see if we can actually pick up. We cannot let's change these two points and we cannot. Let's manually type the attribute name. The attribute, we know that we have created the solar node itself that I have created. That is the at source underscored name, and if that is equal to water. And we need to end this inside of this colon. Let's add this and we do not get any geometry. Let me see what's the problem. Let's go into the MPM and here we have the source name. Let me go into the geometry spreadsheet. And we have this one called mud surface, and we have this one called water height. Okay, so we need to type this one name, water height. Let's go back onto the split node, and we can save water, add an star, which means everything that is above the water. Okay, we have our water, and onto this second, we should get our mud. So let me check. Let's add an null and let's view this. Okay. That is our mud, and onto the split onto this side of the split node, we have our water. Now, let's start meshing both of these simulations together. And first, I'm going to add an timeshift node, let's set a time shift node in here. And the reason I'm adding the time shift node, let me remove this null andlt this and add this in here. Time shift node is that is because, remember, when we were adding this Jeep geometry has an ecdr here you can see, we are adding the 52 frame offset onto this original Jeep animation. Which means that because we are not going to render this geometry, but rather we are going to render this original highrise geometry there we have hot highrise. Let's view this because this one and the collider one, we have the 52 frame offset. So the simulation won't match up. The animation won't sync up together because this will going to be starting at at very back, but if we take a look at the collider, here as you can see we have this Jeep onto the different position because it has an a 52 frame offset, and to actually fix this, we need to subtract the offset value from the simulation. So let's go into the time shift node and onto the expression here we have the Dlo sign F. We just need to subtract the amount that we had added, which is pass the 52. We can confirm let's go back onto our time sheift. Here's can see, we have the 52 frame offset. So now we are subtracting this from our simulation -52. Here by adding -52, we do not have our water particles, and that is because we do not have any simulation data onto these minus frame. So what we can do, we can say that clamp at the very first frame. Onto the clamp, we can say clamp to first. What that will do, it will clamp any value if it going below one, we are going to just simply clamping this onto frame number one, which is the first frame. And once we have reached the frame number 52, our animation, simulation will start start to simulate and animate. And that way, we can sync up with this cheap animation. I hope that makes sense now that we have added the offset, now we need to bring back the other half of our particles, these water particles because that is not our whole water mesh. We are not going to use this as a water mesh because if we were to view our terrain geometry, template this and here is can see, we have the water particle missing because we were using this as an A bound. And to actually bring them back, I can actually bring my this source where we have created this water. Let me see where we have our water particles. So let's bring this node in here, and I can add this by adding the object merge to avoid any messy wiring. I'm going to just drag this in here and that will be the water. And right now it is an A animated, and I think the PM source is creating this into an A animation. So let's get rid of the animation that the PM source was creating by adding the time shift node. Let's add this and let's connect this inhere, and onto the time shift, let's delete delete all of the key frames, the expression, and now we have the single frame. So basically, we are using these static or the static source particles, and we need to subtract the animated one to do that, we have the animated. We want to keep these as NA and our simulation and the particles that are not being simulated, we are going to use this as an static sim. So first, we need to actually subtract the part of the particles that we actually had simulated. And we can add this. We can create this by adding the delete node, and I'm going to delete some of the particles. And right now, it says, delete by pattern. We do not need this disable this. Let's change this to bounding volume. Right now it is removing the primitive, but we want to remove the particles. Let's change these two points and it will remove the points. So onto the bonding volume, let's enable this. Now we can define this bounding box to actually cut off our particles, and we can use our same bounding box that we actually have created with your PM container. Let's copy copy this parameter, and I'm going to go into the elite and onto the size. I'm going to say paste relative reference. And we also need to reference the center as well. Let me go back onto the box, and here we have the center. Let's copy this parameter, and let's add relative reference in hair. Let's click on it. Okay. Now we have linked up together, and these particles now get deleted. Now we can fill this gap with the simulated one that we have in here. Okay? So let's add merge node. Let's merge both of them together. These are our static and these are our simulated, and now we have our whole particle stream together. And now just now let's start actually meshing out these particles. And we can use the MPM surface node. We can add the MPM surface to actually generate the surface. But I'm going to use the VDB method to create the mesh because it will give us good result if we were to add our own meshing with the VDB. So let's add VDB from particles node because we have this particle as an A input. So let's connect this and let's go into the VDB from particle, and we need to lower down the axel size. So let's start this with 0.01. Let's see, and we cannot see our mesh because our voxel size is still too high. So let's lower down this axel size to add more resolution. So maybe let's start this by adding the zero point double 05 and let's see if we can see our mesh. Okay, here we have here we have our SDF represented mesh, and right now, I can see that we have these particles looking mesh, and right now it's not smooth. So let's add an A VDB reshape node. Let's add an A VDB reshape SDF node. Let's at this and connect this after that. And I'm going to first dilate this and it will just fiber to enable increase the offset. Here you will see that we are just simply adding the dilation on our original mesh. I think the value of default value of one is good. Now we can add another VDB reshape node VDB reshape STF, and now we can actually erode the same amount that we have dilated. So, this VDB reshape node, I can change this to erode and onto the erode, we have this renorm accuracy. So maybe let's change the different algorithm. We have the second order of binding. Let's change this to fifth order. Let's see. And I cannot see a whole lot of difference in both of these method. And right now, we do not have the smoothness in our SDF. So maybe let's add an A VDB smooth SDF node. So let's add an A VDB smooth here we have VDB smooth SDF. Let's add this and maybe let's add after we have added the reshape onto the erosion level. And now here as can see we have smooth out this mesh. Let's go into the smooth SDF. Maybe let's change this renom accuracy. Let's change this to second order of binding. Let's see if that give us some good result. And it looks the same to me. So let's keep it as is. And now we just need to convert this into polygonal geometry because right now we have the SDF and we need the polygonal geometry. So let's add an A VDB convert node, and we just need to convert this into our polygons. In here, right now, we're converting this to volume, but we want to create an polygonal geometry. Let's add an a polygon soup. Convert this into polygon soup. Polygon soup is more efficient way of generating the mesh, and we are going to use the polygon soup. So let's add this. And here you can see we have an very dense mesh. So maybe let's play around with the value of adaptivity to actually not create that dense mesh. So let's change this to maybe value of 0.01, and here you can see now we have an a very light weight. Mesh, we do not have resolution where we actually do not need, and that will create a very light weight cache. So let's keep it like and now on top of that, let's add an some post animation because, you know, this middle section is simulated, but this section is not. It is an attic. And after that, maybe let's add an as windy noise animation so that it won't look just static. So for that, I'm going to add an mountain node after we have converted this into polygam soup and let me view this. And right now, we are getting this very chaotic noise. So let me play around with the perimeter of the noise. First, we have the zero center that is correct, and the amplitude is set to very high, so maybe let's not use that much amplitude. Going to lower this value down to very low value, maybe 0.08 and let's see. Here, as you can see, we will have just a little bit of deformation. Now let's animate this by animating this offset. And right now, if I were to enable this here as you can see, we are adding the offset on all of our axes. And we want to animate this Z axis only. So let's separate this offset by clicking on this X Y Z button. Now we have offset on this separated on X, Y, and Z. In here, I'm going to use an A dollarge time expression by adding the dolosignT which means the time, and now we can view this. It was actually generating this again. So maybe let's go back and now we are ready to generate our mesh. I'm going to just move, sorry, not this one, but only these two node onto this side. And I'm going to just duplicate all of the setup where we have converted and generated the mesh. Let me rewind to very first frame, press and hold the old key and rag. And we just need to connect this in here, and all of these things will work fine. We do not need to change anything. Let's going to the convert VDB node, that will generate our mesh. Okay, that is our mud mesh. Now we need to create the water interior. And for that, I'm going to just after we have added the merge, where we have these particles, I'm going to add this one the VDB from particle node again that we had just created previously. So let's add this, and I'm going to connect this in here. And this one, now I'm not going to use the surface VDB, but we are going to use the fog DB because we will going to be using this as an A interior for rendering. So we need the fog VDB and I'm going to lower down the axel size or maybe let's load this down to value of 0.01. Here you can see, I still cannot see any of the volume and that is because the particle scale because we have the P scale and that is very low, that is too low than this ax or resolution to fix this, maybe let's increase our particle scale. I'm going to let's change the value to two and let's see if we can see. Okay, here you can see, we have this volume. Let me zoom in, and here can see that is our interior volume. So after that, let's add another file cache node, and let's write out this cache as well. I'm going to connect this. This will be our water interior. Same thing. I'm going to just remove the toll sign hip name expression. And now, at this point, we are ready to write this water mesh as well as the water interior. But right now we are not going to writing our cache of this mud, and that is because I'm going to add an wet map in here, the wet attribute onto my this mesh. So when mud hit the water, I want this to get wet. And for that, we need to actually create the wet map. And once we have created the wet map, then we can write out our mesh. So first, now you can write out your water mesh as well as the water interior because that is done. And in the next lesson, let's create the wet map for this mud. 11. 11 Generating Wetmap Demonstration: Let me demonstrate you the method that we are going to use to generate wet maps. Let's go into the node editor and let's add an EMT node, dive inside. First, I'm going to create an A grid. Let's say that that is our mud or this ground plane, and I'm going to increase the size of my grid. Let's increase this onto the rows and column. Let's change this to 100 by 100 to add bit more resolution, and I'm going to create an a sphere in here. Let's add an primitive sphere. And let's say that that is our water, and we want to transfer the wet attribute from the water to this grid mesh. First, I'm going to animate my sphere. Right now, it is just sticking here. I'm going to add an A transformed node and not on the grid but onto the sphere. Let's enable the parameter. Let me view the transformed node. And I'm going to use the sine function to actually create an circular animation. For that, onto the translation X, let's use the sine function. And for that, we are going to input this with the dollar sine F, which means the current frame. And I know that the doline F will going to give us a very low frequency sine wave. So maybe let's multiply this by five to actually generate a very high frequency sine wave. And we also need to add the cosine onto the Z to generate actually the circular animation. Onto the Z, I'm going to add the cosine function, and same thing, I'm going to use the Dlo sine F, and let's multiply by this by five. Let's view the result. Okay. Now our sphere is spinning in the circle, but right now the amplitude is too low, so maybe let's increase the overall amplitude for the sine function. I'm going to just multiply by this by five. And that will just increase the amplitude of our sine function, and we need to do the same thing for our Z as well. So let's multiply by this five to actually generate high amplitude sine function. Okay. I think now that we have a good enough circular animation, the amplitude is good. Now, let's create an wet attribute in here. I'm going to create an attribute wrangle node in here and maybe let's connect this into before we have animated this and that way we are not going to just animating this attribute wrangle every frame. Well, not that it matter because it's just a one point, but I think it's a good idea to just add this before that, and I'm going to create an A wet attribute. So that is floating point attribute, so just type F at the attribute name, and I want to create an wet attribute, let's set this value to one. And I'm going to just duplicate this attribute wrangle onto the grid side as well because we need the wet attribute on this grid as well. And for this one, I'm going to set the wet attribute to zero. Now we just want to transfer this wet attribute onto this grid, and we can do this by using the attribute transfer node. Let's add this and it has two inputs, the transfer to and to transfer from. Let me view the attribute transfer node and to actually visualize this wet attribute, let's have over the attribute transfer. Click on this high button and click on this wet attribute to actually visualize. Okay, that is our wet attribute, and right now the radius is too big, let's go into the attribute transfer onto the condition. Let's lower down its distance threshold to maybe let's say value of one, and right now we have these jagged edges, so let's maybe smooth them out by increasing the blend width. Let's change the 21 as well. Now we have a very smooth fading of this wet attribute. Now if we were to hit play, and here can see wherever we have our sphere, our wet attribute is transferring. But it's not sticking. It's actually moving with sphere. If I were to template this transform node, here as you can see it is moving where our sphere is. But we want to leave an a trail because the wet map it just not going to disappear like that. We do have some trail and to actually add this trail, we can use the solvent node. In here, if you type the solver, here we have it. And this is a dynamic node, which means that it needs to be simulated. So it's basically an a solver. I will going to be simulated. So let's connect this onto our initial geometry and onto the second input. Let's add this into our auxiliary, and I'm going to just remove this from here. Let's remove this and let's go into the solver node and dive inside. And in here, we have some of the nodes. First, we have these inputs. We have this input, four inputs, and these inputs actually correspond to these guys, these inputs, we have one, two, three, four, we have the input one, two, three, and four. And the main thing that we have is this one, this stop node that is the previous frame. It will remember the attribute. It will remember what happened on the previous frame and it will accumulate over time. So it this node basically has a memory. This node remembers what happens on the previous frame, and we can use this to actually accumulate our attribute. I'm going to rest attribute transfer node in here and I'm going to just connect this onto the previous frame, and I want to import from my second input. Remember, our sphere is in the second input. Let's connect this in here. And let's connect this onto our out node and let me set the display flag to be out and let it play again. And here as you can see now we have the accumulation. Now this node is remembering wherever it has passed through and it's not getting deleted. Now it's remembering them because it's getting the information from the previous frame and it knows what happened on the previous and it's add that and same thing onto the next and to the next. And actually keep remembering this and keep adding this onto our current frame. That is good. Now we can actually fade this because right now here as can see the attribute is not fading, which means I can basically add an A attribute adjust node. That is an a float. So let's add an attribute adjust floor and I'm going to add this in here. Right now, it's using the B scale, but we want to adjust our wet attribute. And onto the operation, I'm going to, let's say, multiply this our value with an A some lower value. Until right now the constant value set to zero. That is why we do not see anything because we are multiplying our t attribute with zero, so we do not get anything. I'm going to create an L exchange this two value of 0.9. And that way we are multiplying 0.9 our current wet attribute with 0.9. So which means that we will going to be getting an fading effect if I were to hit play, and hers can see we have this fading effect because at every frame, wet attribute is going to be multiplied by 0.9, 0.9, and hers can see the first at the very first, where we have the solid wet attribute, over time, it's going to get faded and we have this fading effect, and that is good. This setup is clean and neat and simple, right, but we cannot use this in our situation as to why. Well, that is because we have this our Mud geometry is animated as well. And right now, the grid is not animated. And let me show you if I go back onto my this grid, let's say if we were to add an A animation, let's animate this. And I'm going to animate this by using the mountain load. Let's add a mountain let me connect this and view the mountain node. I'm going to just increase the amplitude or also the element size as well. Let me keep increasing the amplitude, and let's also animate this onto the attribute noise. Let's enable the animation. Flats hit play. Okay, now we have the animation on our grid as well. Now let's see what happened. If we were to view the solvent node and hit play and here as can see, we do not have our animation. Our animation is gone. Basically, we are getting the very single frame. And that is because onto this first geometry, when it go into the solver, this previous node will always look for the previous and it's not updating what's happening on the current frame at the first geometry. It's updating the second because we are basically importing the input to but the first input that we have actually there, input one, we are not using this, but we are using the previous frame. So it always look for the previous frame and it does not know what's happening at the current frame with the first piece of geometry with this geometry, if I were to go back and this one, it does not know what's happening at the current. So we basically get our static geometry, and our animation is gone. And to actually bring back our animation, we actually do not need to use this previous frame to actually transfer to, but we are going to use this one input two, and we are going to leave the top important in here for now. And now because we are using the input and not the previous frame. And if I were to hit play, here as can see, now we get the same result basically that we had on the hop level because right now, are actually not using the previous node, which means that we do not know what happened on the previous, so it's actually just updating what's happening at the current frame. And to actually get the information back this previous frame information back, let's import this from the dub input. And the way we can do that, we can basically add an attribute copy node. So let's add an attribute copy or maybe attribute combined. Let's add this and I'm going to add this into there and from the previous frame, the second input and onto the attribute combine the destination attribute we need to define and the destination is wet and the source attribute is also wet. Let's change this to wet. And here it says, what is the source? The source right now is using the first input, which means that it's going to look wet from the first input and at this. But we want to look at the second input because we want to import the wet from the previous frame. So that is our correct input. Let's go into the attribute combine. And let's change the source, and that is not the first, but the second context. Okay, now let's view the result and heres can see. We have our animation back, and we also getting this fading and this fading is actually coming from the attribute just if I were to disable this and let's view the result. And heres can see we are accumulating over time. So we are remembering what's happening and we have animation. And that is well and good, but we cannot use this method as well. I mean, we are going to use this method, but it's actually not enough. We need to adjust a bit more as to why. And that is because right now we are using the geometry that its point count is not changing. So every frame, we have the same piece of geometry and we have same number of points if we were to view have same number of points. So the topology of our mesh is not changing. It's the same on every frame. There are points. They are just moving around, but the geometry itself is actually not changing. It's deforming, but it's actually not changing. But in our case, our geometry is varying. Our point count is varying. And let me show you how I'm going to duplicate the solver node, this whole setup, and I'm going to replace this with the mesh that we have. And for that onto the grid, I'm going to let's remove the mountain for now. I'm going to add an extrude volume load to actually give this a bit thickness, this grade a thickness. Let's add this and we are using the extrude old node, but let's remove this and let's add an extrude volume node. Let's add this and let me go back and connect this in here. And that will give us the volume, and here we have it. I think the thickness is enough. We do not need to adjust this. And now we just need to convert this into VTB volume. So let's add an VTB from polygon's node, and I'm going to connect this and let's use the surface VDB and for this example, we do not need that much axel size, so maybe let's increase this 20.4 to create very low resolution of VDB, and that will just very fast to calculate. And after that, let's add some noise to add some breakups onto this mesh. And for that, I'm going to use the volume nose noise node. Let's add a volume noise and volume noise SDF because that is our volume SDF volume. Let's go into volume noise, and right now we are using the zero centered value, and that is fine. Maybe let's increase the element size. Let me keep increasing this, and let's also keep increasing the amplitude as well. Let's keep increasing this until let me see. And it's not animated, so let's go into the animation and let's enable the animation. And here as you can see, we have the noise that is actually changing over time. We have this mesh topology that is changing. Now we just need to convert this back into regular geometry. Let's add an convert VDB node, that's SD and I convert, VDB, connect this, and I'm going to change this to polygon soup and polygon soup will a bit more efficient. So let's go into the adaptivity, and maybe let's change this to 0.1 because we do not need that much of geometry. Let's view this. Let's hit play. Okay. I think that mesh is good enough. Here you can see the point count, the topology is actually changing over time. It's not staying the same. In that case, if we were to, let's add an wet value to zero and maybe let's connect this after when we have animated so that we are not going to calculate this attribute wangle over time. Now if we were to visualize, here we have the wet attribute and now let's see what happens when we go into the solvent this and let's it play. And here as you can see, we have this wet attribute that is jumping all over our Her mesh, and that is because the point count is not changing. And if we were to go into the solvent node and this attribute combined node that we are actually using to import this wet attribute from the second input from the previous frame, it actually require the same number of points, same number of count of points to actually work. But we do not get the same number of point count on every frame. The mesh that is on the frame number one, it's actually not the same at the frame number two. So that's what actually confusing the attribute combined node to actually jump over this wet attribute. We need to fix this. And to actually fix this, we are not going to use the attribute combined node, but let's use our own x node, good old attribute, wrangle node to actually import the attribute from the previous frame. Let me connect this in here and let's connect this onto the second input. And, you know, to actually import the attribute from the second input, we have a node we have our x function called point. So I'm going to just, let's say that create an A float variable and I'm going to call this one float wet and float wet from the second input. So I'm going to call this one float, wet, maybe previous. Float wet P, which means the PVs. And let's import this from our second input. And we can use the point function. So let's add a point node. And in here, we need to define where we want to import, and we want to input from the second, which means we can say 10 mean first, one mean second, and the column the attribute name, we want to import the wet attribute. And we need to define the point number from which point actually we want to import. And we can use, let's say, add PTNum. Let's add this. And let me close this point function and let's add an A sem column. Now we have the variable, float variable, the wet P, and now we just need to add this. So let's inhere, I'm going to say that our F at wet, which means that look for the wet attribute, and let's add this. Look for the current wet attribute, and let's add the previous frame wet that we are actually going to import. So in here, we just need to type the variable name, which is the wet P, and I'm going to just add an SEM column to actually the argument. And now let's see. And here as you can see, we are getting the same thing that we were actually getting from our attribute combined load. That is because we are still using the same thing. We are using the at PT nu, which means that look for the current point number and the current point number is actually not the same as we have at the previous frame. And that is why we actually need to replace this with an A near point. For that, onto the attribute wrangle, we have the Near point function. If we were to type in here, we have the Near point function and we can also take a look at the point Cloud lookup if we were to type Point Cloud, we also have the point cloud node. Let me type. And right now, I cannot see that, but we have the point cloud lookups, all of these wax function to actually get the near point. But in here, we also have an node called proximity, if you were to add this, and this node will actually create the same result with the wax function, we have the near point. It will look for the nearest point if I were to add this. So that is our first geometry, this geometry, and we were to cure the nearest point from the second piece of geometry, which actually happened to be our previous frame. So let's connect this in here. And onto the proximity node, that will give us the nearest point, which means that this point, for example, if I were to enable the point number, let me enable the point number. So let's say we have the point number 5770 that will going to look for its nearest point onto the next frame, and that way we are not going to break this at PT num because the point number is actually changing and we are updating this with this proximity node. It will look for the nearest point and it will store into the nearest point attribute. That is a big name, so let's change this to NRP, which means the nearest point. That will give us the nearest point from the previous number, which means now we just need to replace this at PT num with our at NRP attribute, which means the nearest point. At NRP, and let's view this and right now it's throwing this error because it does not know that it is an float or integer, so let's help this by typing the I, which means we are explicitly telling that that is an integer attribute. So let's add and Hers can see we have this error gone. By the way, that was not an error. It was just an warning now if we were to hit play, and hers can see, now it's working fine because we are looking for the nearest point and that this near point won't break on every frame because we are not actually setting that look for 577 point because 577 point, that is right now, let's say, in this corner on the next frame, it might be on this corner, so that's why it was breaking. But because we are looking for the nearest point, this attribute always changes according to the mesh location, and that's why we are getting this stable result. So we actually need to use this method. And right now we are adding the wet attribute onto every frame, which means if we were to go into the geometry spreadsheet and take a look, here we have the wet attribute. And if I were to scrub my timeline, let me click on this to actually view the maximum values. And here as you can see these values are actually keep adding on every frame. So that is not good because we are seeing in our x that add this. So we actually do not need the values beyond one. So what we can say, we can actually limit this wet attribute with adding the clam function, or we can actually say that bring the max attribute from this from this second point. So the max attribute is actually one. It does not go beyond one, as you know, because we are setting this value attribute angle onto the one. So that is an A maximum value. It won't go above then that. So onto the solver, let's say we want to say that please do not add this on current frame, but give the maximum value. And for that, we are going to just, let's say, our F at wet, and that is equal to we need to get the max value. So in here, we need to type the function max. And I'm going to say, please look for current wet attribute. So I'm going to say at wet, which means that look at the current wet attribute and also look for the wet P, which is actually coming from the second input. And let me give what's the max. And I just need to add the bracket the ending braces in here now if we were to see. And here is can see because every frame when we are going to import this with the attribute angle, changing this value to one and now because one is an a maximum value, so it's actually picking from the one so that way, we will not going to be getting values any higher than one. If I were to go back, let me into the Solver node and scrub, and if I were to change this He's can see, we have these value zeros, and we will only get one. We are not getting above one, and that is the setup that we are actually going to use. Okay? So now, let's implement our setup in our actual project. Let's do that in the next lesson. 12. 12 Creating Wetmap: Now let's generate wet maps with the method that we have previously learned. Here I have this mud mesh and I want to add the wet attribute or this mud hitting the water for that, we need the water. If I were to view this merge, where we have actually these water particles. If I were to zoom in and here is conceit is a water particle, these are not mesh. We have this mesh here in here, but we are using these water particles. So I'm going to just add an attribute wrangle in here and I'm going to connect this at the merge where let me connect this onto the first input, and maybe let's move this up here, let's call this one attribute wrangle to set wet to set the wet attribute. In here, I'm going to generate an floating point attribute, so F at wet, let's initialize this to value of one. And now we just need to duplicate this wet node, so present hold and hold key and track and snect this onto the convert VDB where we have this mud mesh. And onto the Mud mesh, I'm going to set the value to zero. So now let's transfer this wet attribute from water onto this mesh. And I'm going to add solver node in here for that, and I'm going to connect this one to the first input. That is the mesh, and onto the second input, let's connect this wet. And maybe let's add an A null in here and I'm going to connect this. Maybe let's place this and make these lines straight. And I'm going to call this one water particles because they are water particles. Let's view the solver node, and let's dive inside. Let me click and let's dive inside. So now here we are in the solvent node, and here we have the inputs, these different inputs, and we have the previous frame. And let's bring the previous frame down here and let me move the out node to the down. We need the input one and the input two. Let's add an attribute transfer node. And let me connect this one and let's transfer this from the hackin input. Remember, these are the water particles and let me connect this at the end. That way we can go into the attribute transfer. I here. I will transfer all of the primitive endpoint attributes. So maybe let's uncheck this and onto the points, let's specifically that we want to only transfer the wet attribute because if we do not set the wet, if we leave this field empty, it will transfer all of the attribute, but we just want to transfer only the wet attribute. And now let's visualize this. Let's go into the geometry node and onto the solver, let's click on this I button, and onto the wet, let's click on it, and Houdini will add an A visualizer. And here as can see we have an A value of red, which means that the mesh particle of all of the mesh is getting the value of one. So let's go into the solver node and onto the attribute transfer, let's go into the condition and adjust this distance threshold. And for this, I'm going to just zero out the distance threshold. And instead, I'm going to use the width attribute, blend width. So let's add the blend with to an a value of 0.5. What that will do, it will give us a very smooth fading this wet attribute and that will look natural. And here you can see where we have the red, which means that this mud mesh is actually submerged in the water. So we have the wet value of one, and when the water moves and the mesh will actually going to be moved around with our vehicle, it will touch the water and it will get wet. So let's keep it at 0.5 and to actually make these values to be remembered. By the previous frame, we actually need to take care of this previous frame, this top import node. For that, we know that first, we need to add the proximity node because our mesh is changing every frame. And we want to get the near point from this previous frame. Let's go into the proximity node, and it will give us the nearest point on this attribute. Let's change this one to NRP for an a short of near point. And after that, just add an A attribute wrangle node, and we want to import the attribute from the previous input, which is the second input. Let's go into the attribute wrangle and in here, I'm going to create an A float variable, the previous. Let's type in an A wet P and we want to import the previous t from the second input. So let's use the point function, and I'm going to import this from the second input. The attribute name, that is the And for the point number, we are going to use the NRP that we had created. So I at NRP nearest point that this proximity load is actually outputting. Let's go into the attribute angle, so that will give us the previous wet. Now, we need to set our wet attribute. In here, I'm going to say at wet this new wet attribute. That is going to be an A max. Let's add an Amax function max of our current wet, current wet attribute, and the wet P that we are actually importing from our previous frame. Let me type the wet P and let's end this. And with that, we are done with creating our web maps. Let's go back onto the geometry, and after the solver, let's add an file cache node. Let me connect this, and I'm going to call this one our MUD mesh. And let's go into the file cache, and let's remove this tool sine base name expression. I'm only going to use the dol sine OS. And before we actually write out this mud mesh, we now only need one last attribute, and that is the rest attribute because later on we are going to add the texture on our mesh. And right now we do not have UVs. If I were to middle mouse button here as you can see our mesh does not contain UVs. So I'm going to use an triplanar projection to project our texture and to actually make our texture stick onto our moving mesh. We need the rest attribute. So let's create the rest attribute in the next lesson. 13. 13 Create Rest Attribute: Let's create the rest attribute onto this mud mesh because later on we are going to create the triplinar projection to create the material for our mesh. So in order for the material to actually stick onto the mesh, we need to create the rest attribute, and for that, I'm going to go back up here where we have the simulated particles onto the merged node. Here you can see we have these particles, and right now they are animated. Here you can see we have this clock sign, which means that we have the animation and this simulation animation. So let's first strip out this animation by adding the time shift node. So let's add at shift. Add this and connect this in here and onto the timeshift, I'm going to just remove the expression from the frame, so let's click on it and let's say lead channel. And that will remove out the animation. Now we have a snapshot of an a single frame. Now, we need to create the rest attribute onto these particles. So let's add an rest attribute, and that will create the rest position for us. Let's add this. So this rest nude will actually just store the current point position in attribute called rest. And now let's convert this into VTB. So let's add an A VTB from particles node because we are using the particles in here. So let's add this onto the VDB from particles. I do not want to create this surface VDB. Let's uncheck this. But we want to convert this rest attribute into VDB. So let's go into the point attribute and click on this plus icon. And in here, we can set A point attribute to create the VDB. So onto the attribute, I'm going to just pick the rest position where we have rest that is called actually the rest. Let's set the VDB name to rest as well. And onto the vector type, we can say that that is an A position. So let's change this to position, and let's view the result of our PDB from particles. And here as you can see if I were to middle mouse button, we have the rest VDB, but we have the zero resolution, which means that our boxel size is too big and our P scale value is smaller. So let's slow this value down to an A value of 0.06, and I still can't see that. So let's other zero in here. Okay, now Hers can see our rest attribute has been generated. I can see with this cloud, this fog looking that is basically the rest volume. And if I were to middle mouse button Hers can see, we are right now using very high resolution, and we actually do not need that peak resolution. So in here, maybe let's add an VDB resample node, VDB resample, and let's connect this. Okay, onto the VDB resample, right now, it's using the transformation from the transform from the to match the reference VDB, which means we need to set into this rest one. But I can say that I want to use the axel scale only. So onto the auxel scale that we are going to use this value of a two. So if I were to middle mouse button, and heres can see we are drastically lowering down this auxelRsolution. And that will create an manageable resolution because we do not actually need that fine detail of this VDB, we only need the position, and that will just work fine for us. And now we just need to transfer the position information that is actually in the rest onto this mesh, where we have our mud mesh. Let me visualize here we have this. So to actually import the attribute from the volume because here is can see that is another volume, and that is our mesh. We can add another attribute wrangle, and I'm going to connect this in here. Let me connect this and let's connect this onto our second input and move this down to create this straight line. I'm going to call this one Import rest and onto the angle, let's create an rest attribute. So that is an a vector. So we add rest and to actually import the rest because that is a volume, we have a node called volume sample. So let's use the volume sample volume sample. So volume sample mean that sorry, we are using the volume cubic sample, we do not need the cubic interpolation, but we only need the volume sample. Here we have the volume sample V. I can add the bracket in here, mean that we want to sample the vector attribute. If I were to remove the V, we have the volume sample function. That is used for importing the floating point attribute, but because position is in a vector, so we have function called volume sample V. Let's add this. And now we need to say that from which input we want to import, that is the second input. So let's change this to one. And in here, we want to we need to define the name of the VDB, and that is called the rest, and we need to define the position. And we want to sample these voxel at our current point position. So in here, I'm going to just type the at B. Let's close this at this with our semiclum now if I were to view my import rest, and if I were to middle mouse button and here is can see, we have the rest attribute. And that way, now we can import this rest later on in the solas, and we can create our material and make our texture stick onto this moving mesh. Now, at this point, we are ready to write out this mud mesh cache. So let's go into the mud mesh, and in here, just save two disks to write out all of our caches. 14. 14 Painting Mask For Material Blending: Okay, I have written out all of my caches. Now let's go onto our terrain where we have created our terrain mesh. Here we have this terrain. Now let's generate the mask for our texture for the terrain because onto the terrain, we are going to use the two different material and for that to blend these two different material, we need the mask because I want the first material for these tracks where we have the way for our jeep. Let me find where we have this, where we have HirasJep. Let me template this Jeep mesh here can see if I were to move this Okay. So wherever we have this moving, we want to create a mask to actually set different material for these tracks. And for that, let's go onto this outing. And from this null, I'm going to create an texture print mask. Texture mask paint. Let's add this node. And on this one, I'm going to connect the null where we have our out rim. Let's add this. Let me go back. And let's visualize this texture mask paint node, and onto the viewpoardH to the viewboard press Enter to so that we have the access to its manipulator. And now I can just start painting. And here can see when I paint nothing is happening, and that is because for this node to work, it requires the UVs on the mesh. And if I were to middle mouse button onto my out terrain, and here as you can see, we have the UVs, but they are at the point level. As you can see, we have the UV as an point attribute, but it requires the UV onto the vertex level as an a vertex attribute. Here, let's add an A attribute, promote node, and let's connect this. And I'm going to rearrange this onto the attribute promote, the original class is point. Let's set the name. That is the JUV and the new class, let's change this to vertex. And now our texture paint mask should work. Now, let's select the texture mask paint node, how to the Vpot and press Enter. And now if I were to start painting, and here is can see now I am able to paint. Press control Z to undo, let me hide by this view ple and grid, and let me adjust the viewing angle, and I'm going to play around with my brush, where as you can see, we have the radius, control shift and left mouse button to drag. So let's press Control and Shift and left mouse button press and hold the left mouse button and drag to adjust the radius. And I'm going to set the radius like so, and I want to just start painting from here. And right now, hers can see the stroke is right now, the stroke is too hard and we do not have the fadiness. So let me undo this. Let's go into the texture mask paint. And here we are painting the mask name attribute is mask, and that is good. Here we can define the resolution. The resolution is fine, too. We do not need any more high resolution than that. And I want to play around with these soft edges. The soft edges is right now half. Let's change this to one to create more soft edges. And here can see we have the softness and maybe let's play around with the opacity too. So let's change the opacity to 0.5 and let's see. Okay, I think that will give us a good fadiness. So wherever we have the wheels, I know that the wheels are starting here, so I'm going to just click and draw like so at the end and like there. Let's add another stroke where we have these wheels, let me click, and let's keep adding this. And that way we have these tracks, we are going to use the mask to create blend these two materials, and I'm actually going to add a different material onto this corner. So let's add a paint and also add the mask in here. I'm going to use the same material, so that is why I'm actually mixing the mask. I'm adding the same mask because I want to add onto this white part, same material and all of this gray part, other material. Maybe let's continue painting this. I'm going to paint this where we have all of these edges. And maybe let's paint this onto our inside as well because where we have the or the ground where we are water or flowing, I want the same material, too. So maybe let's fill out this with this our mask and I'm going to keep dragging this, adding these strokes. Let me view. Okay. That is fine. Let's fill out all of the interior. And that we're going to use this to blend material. Now that we have our mask, let's save this out onto our disk, and then later we will going to import this mask into our material for blending and to actually route out this mask, we can use this a height field output node. Let's at a height field output, we have the height field output. Let's add this. And that is because it will generate an A volume if I were to middle mouse button, and if I were to, let's say visualize, that is the first input, that should be our original mesh. Hers can see, nothing is changed, we have the mesh. Onto the second input, we have the volume. Hers can see, I can see this as an A plane. But if I were to middle mouse button, hers can see we are using the actually axel size, which means that that is an A mask volume. And it is similar to the height fields. So which means that we can use the height field output node to actually write out our mask. And here I can see that we have some leftover this gray stroke, which means that we need to go back and actually fix this. So let's hit Enter again and let's fix where we have missing. Let me see. Let me click and drag click and drag in here so that I can we have this full white, and here I can see some of the blackiness let's paint this in here as well. Let me zoom in change the angle. And now let's view this again onto the texture mask. Let me activate my camera view tool and let's zoom in. Okay. Now, let's connect this onto this height field output node because it is expecting the volume and the second input is the volume. Let's maybe remove this onto the height field output. Let's go in here. We need to define the file name as well as the location. So let's pick up the location, and I'm going to go into the I dollar sign job. Let's save this onto this texture folder. Let's click on it, and I'm going to call this one mask. And in here, we can type the mask dot PNG, and I want to store this mask as an APNG. So let's type this and hit Accept and format is the RGBA, which means that it is red, green, blue, and Alpha. But because it is a single value, we can change this to a single channel. And the type is 32 bit floating point and we do not need that much precision for this simple mask. So let's change this to eight bit fixed. That will work fine for us. And onto the red channel, we need to define the volume name. And if I were to pick Herscnc we have the mask. So let's click on it, and that will pick the mask attribute and store it onto this first channel. And now I can just press save to Discption. Let's click on it, and Houdini will start to create our mask. Okay, mask generation has been done. We can confirm. Let's go into the project file directory. Let's go back and here's can see we have this texture folder. Let's dive inside and here's can see we can see the mask. Let's double click to open this and let me make this window a bit smaller so that it fit on my recording area. Let me select and let's make this window smaller. Here's can see we have our mask generated, and this will going to be used in the rendering process. Let me close this window and now in the next lesson, let's add the grass onto this terrain onto this terrain. Okay, so let's do that in the next lesson. 15. 15 Scatter Grass: Let's scatter some grass onto our terrain. Let me go into our terrain and we have this terrain. And after we have created this attribute promote and added the UVs onto this vertex level, I'm going to add another texture mask paint node because I want to paint where I want the grass to grow. Let's add a texture mask paint, and let's connect this and let's view the texture mask paint. Select the node, press Enter to access its manipulator. And in here, let's start painting where we want the grass to grow. First, I'm going to increase the brush size. So control shift click and rack that we can increase the size. Let me see the brush parameter, soft edges. Let's change this to one. Maybe let's lower down the opacity to 0.5 to create a very smooth smooth mask. So let's start painting. And I want the grass to grow in hair. Like so let's create an patch in here. Something like that. And let's create another patch right in front of it. And also, we actually need to avoid where we have this track. So I think that our track line is in here in the front of the wheels. So we need to stay clear of them because we do not want the grass to grow onto where we have this way where we have these tracks. Let me start painting, and I want to add some of the grass patches in here as well. And because that is the actual area that we are going to see, our camera will be like here. So I think this mask is good. We do not need to paint in hair as well as in hair because we are not going to see it anyway. Okay, so these are the patches where I want the grass to grow. Now we have the mask on the texture mask pane. Now let's add an A scatter node. So if we type the scatter, here we have this scatter that is used to scatter onto our geometry, and we also have this one scatter in texture mask. So let's add this node because we want the scatter node to actually consider our mask that we have drawn. And the first input that is for the geometry. So that is our geometry that is coming from our texture mask. The second input is the mask, so that is our second input. Now if we were to view the scatter texture mask, that is ring and error. Let's see, why is that, that is because it is looking for the texture path, which means that we can select the texture that we might actually have onto the disk. But because we are using the live node, so let's go into the scatter in here. Let's change the mode from texture parts to actually texture primitive, which means that look for the mask primitive, let's click on it, and Hers can see we are using the mask primitive and that way we can actually make the live connection, and Heres can see we have these grass points. And we are getting some of the clumpiness, which is actually good. But we can go into the texture mask and we can lower down the relax iteration to actually add the randomness. So maybe let's change this to one, and that way we have this enough randomness and also the clumpiness. But the point count is too high. So maybe an A density of thousand is too high. Let's change this to an A value of 300. Okay, so the density of 300 value is fine because we do not want to create that dense grass, and that will work fine. And now just import our geometry the grass models. And for that, I'm going to use the file node. Let's bring up the grass models that we have downloaded. Let's go into the Dlo sign job. They are in the assets. Let me find they are actually in the Geometry node, not in the assets. So here we have the grass medium. Let's go in here. We have this FBX, let's grab this and hit except let's view the result and the grass came in a very huge size. So first, let me template this Jeep geometry by clicking on this button and clicking it again. And now I'm going to add an A match size node to actually lower down the size. So let's click on it and justify Y set to center. Let's change this to minimum, and that will make sure that grass it onto the floor. Let's also click on this scale to fit option to scale this onto this one by one size. Now, if we were to zoom in and here as you can see we have our grass imported. So now let's start grabbing the grass one by one because we want to add all of these different variations on the grass. So let's start grabbing them. We can add an A. Let's say, let me add plast node in here. And I'm going to, let's say blast this with our name attribute. Okay, here on to the name, we have the cross. So maybe let's start this with an very last value T. Let's click context non selected. And here we have this big cross. And right now, hers can see it is slightly offset it from the origin. So after that, let's add another match size node. And for this one, that will just center out X Y and Z and onto the YS chain is to minimum. And now we will get our grass close to the origin. And that is important because the Houdini will look for its origin to actually scatter them onto the point. So we need to make sure that they are sit onto the origin as close as possible. And after that, let me see okay. So here we have some of the unnecessary attributes that we actually do not need. So let's add an A attribute. Delete node after the mesh size or before doesn't really matter. So let's add this. Let's click on this delete nod selected to actually remove all of the attribute, and we want to preserve the let's say, which one? Let me middle mouse button. So we want to only preserve the name and UVs. So let's go into the the name attribute that is an formative attribute. So let's click on this let's select name and onto the vertex, let's select the Ubis. These are the attribute that we actually care about. And now if I were to middle mouse button, we have the name and UIs. Maybe let's add normal in hair as well after we have created this blast node where we are isolated. Let's add the normal, and now we have the match size. Okay. Now I'm going to just duplicate this another time. And for this one, I'm just going to go into the Blast node and just start typing out this reference. The D, now let's go back onto the value of E. Let's change this. So now we are using the E variation. Let me select all of them and blast. Let's use the C value, the C variation. Let's click and drag and this one to be our B and let's click this track this one more time. And this one, I'm going to use the first variation, the variation A. Okay. That will give us a very good variety. Let's add an emerge node to actually merge all of these variation together, select all of them. That means select all of them and connect this onto the merge, select and connect. Let's view this. Okay, now we have multiple variations on top of each other to actually make these copies differently onto these points. We need to transfer the name attribute from the geometry, this name attribute onto the points, and for that, we have the node called attribute from PCs node. So let's add this and that require the point cloud, that is the point loud and the geometry library. That is the Geometry library. And it is already set to transfer the name attribute. Right now, the mode is set to cycle. So maybe let's change these two patches because I want to create different patches. So maybe the first patch, we have the variation one and onto the second patch we have the variation B. So all of these variation will come in patches and not actually cycling. And you can define the patch size in here. So maybe now let's add copy to points node to see that which value we should be using of the patch size onto the attribute from pieces node, and it requires the geometry. These are our geometry, and these are our points. Onto the copy to points node, first, I'm going to enable the pack and instance because we need the pack geometry. Let's enable the BS attribute as well. Now if we were to view the copied points and here's can see right now the scale is very too low, so maybe let's add a P scale value. So let's add an attribute randomized known. Let me click on it. Right now we are randomizing CD, but we want to randomize the B scale. Here's can see, I can start to see the grass. Let's change the distribution from uniform to let's say uustum ramp now we can actually just define our ramp maybe let's create this random looking ram to actually create the varying scale. And the scale is still too low, so let's go into the global scale and let's increase the overall scale value to four. Okay. And now the orientation is still in orientation is not correct. That is going onto the same direction. So to actually at the orientation, we can add we have and node called scatter and align node. Let's type. Here we have this scatter and align. So this node, it requires the surface to scatter the geometry will scatter as well as align them. But because we already have scattered point, we just need the attributes. So which means we can connect this one, this constraint point cloud, this one, and that way, we can use this to just add the attributes onto our currently generated points that we actually have. Let's go into the scatter and align. Right now the mode is scatter point on geometry, but we only want to add the attribute to existing point cloud. So let's add this. And in here, we have the rotation. So onto the rotation around normal, we can define the mean and max. Let's change the minimum 20 and max to a full resolution of 360 degrees. Now we can connect this and let's view the result of the copy two points node. And Hears can see now we have the orientation correct. And onto the attribute, it is actually creating the P scale attribute as well, but because we are generating the P Scalon by the attribute randomize, we actually do not need to create inhere, so let me uncheck this radius attribute, check this. That way we are only generating the orient to set the orientation. Let's go into the orientation, and here can see by adjusting the max angle, we can adjust the orientation. Let's change this to 360, and now it's just a matter of going onto the P scale and play around with the ramp. And here as you can see, we have the smallest value, so maybe let's not change the smallest to zero, but maybe a value of 0.1, because I don't want the grass to be completely zero, and we can just play around with that value to create a random scale. So you can adjust the ramp to your locking to create the randomness in the scale, and we can go into the attribute from PCS node, here we have the patch size. And here as you can see, as we are making the patch size bigger and smaller, we can start to see the different clumps, the different variation. So we can adjust the patch size. So maybe let's increase the patch size to higher value. Let me view where we have a good looking variation. I'm going to change this to a value of 1.9. That will give us a good randomization onto our grass patches. Now we are ready to write out. We are ready to actually create an a null let's connect the copy to point in here and I'm going to call this one out grass. 16. 16 Placing Rocks: Now that we have scattered some of the grass, now let's import the rocks that we have downloaded. So maybe let's add the rocks in our terrain as well. And for that, I'm going to just create an file node in here and let's load out our rock model. So let's click on this two double dot folder. That way we can go back. And here we have the mos set. Let's dive inside, and let's open this rock moss set. Let me view the result. Here you can see the rock size is too big. As always, let's add an match size node. Let me connect this and I'm going to just click on this scale to fit option to scale this onto a value of one by one. And after that, we have all of these unnecessary attribute. Let's add an attribute, delete node, and after that, I'm going to just click on this non selected, but onto the vertex, want to keep the normal and UVs. To the primitive, we do need the name attribute. So now let me create an APAC geometry because right now errors can let me select this. Hers can see we have all of these polygonal piece of geometry, and to make this a bit more efficient, I'm going to create an APAC geometree. So let's add an APAC and connect this I'm going to click on this name attribute. That way we can use the name attribute to actually create these packed fragments. So if I were to middle mouse button, Hees can see now we have these six packed fragments. And now we can just select some of the rocks that we actually want. So what I would like to do, I'm going to just click on this selection and I'm going to select this and press delete and that will just blast that. I'm going to click on non selected. That way we only have this one that we just selected. And now I can just add an A transform node, and I'm going to connect this transform, and let's see let me see my train by adding this, templating this, and now I'm going to just select let me see where we have this transform load, just select by pressing Enter. So maybe let's move pivt onto the center as well. So let's go pit to center and let's click on it. That way we can move this one. Let me place it around maybe here, I'm going to let's increase the scale a bit higher, and I'm actually going to rotate this onto my Y direction as well. Maybe let's change this and I'm going to place it somewhere. I'm going to pick and place the. Let me move this down. Okay, we are too far down. Let's move this up and place this up bit back, rotate this like so and let's also create another geometry onto the front. So let's go onto the back, and I'm going to make another selection. For this one, I'm just randomly going to select model by pressing the delete node. Just move it onto this side and click on this delete non selected. Same thing. I can add the transform node. And I'm going to connect the transform in here, move P two centroid, and press Enter and move this into the front. It's adjust the overall scale by adjusting the uniform scale. Now we can just place it to manually place it wherever we like. Okay. Let's merge both of these rocks together to better view them. Okay, so right now they are facing each other, so maybe let's go into the trans sorry, not delete, select the node and press Enter and move this in front of it. And now we can create the null at the end, and I'm going to call this one our rocks. So let's type in here out. These are our rocks. And later on, we are going to use this out to actually reference this one we are going to import this in Solaris. These are our rocks. 17. 17 Setting Up Solaris Scene: Let's import all of our assets and geometry in Solaris for rendering. And first, let me zoom in. Here we have the outgrass. Let's create some other of these out null that we are going to use for referencing when we are going to import them in Solaris. One, let's create an null we have the mud mesh. I'm going to create an null after that. So it's actually not this one. Let me select and drag and connect this after the muds mesh, and I'm going to call this one out mud. And same thing. We need to create the null for our water interior. So let's add another null, and I'm going to call this one out water interior. And lastly, let's create for the water mesh. Let's add another null, and I'm going to connect this at the end, let's rename this out water. I'm just naming this two water. Now we are ready to go into Solaris. And let me you can actually create an lob Net in here if you want. I can just right click and in here, I can create an lob network, add this in here and now we just need to dive inside. And now we are in the Solaris, and we can start building our scene by importing our geometries from soap into Solaris. Or, let me remove this lop net or we can go back at the scene level and we can create an elopNt in here. Let's add an elop network. And you can also go into your stage context, and you can start building your scene in here as well. But I'm going to just create the lop net here at the scene level because I think it would be easier for us to find where we have this lop net scene. So I'm going to just create an A onto scene level. Here we have the geometry, and I'm going to maybe call this one Sim maybe let's call this one to be our Mud and Mud effects. And now we just need to import this into lop net. So let's dive inside the lop net and let's start importing our geometries. Let's add an op import node. And let's connect this and first, let's bring up our Jeep model. And out here we have the outcross. Well, by the way, the order doesn't really matter. I just like to import it like this. So first, I'm going to add import the Jeep. So let me find where we have out high ras Jeep except and I'm going to rename this accordingly. That is our Jeep, because that is an APAC formative, we actually need to adjust some of the attributes onto the sap input. So if we were to, let's say, we see the scene graph tree of this Solaris. I can view this. If I click on this plus icon, let's go into the new pin tab and we can go to the Solaris and let's enable this syn graph review. Let's click on it, and here can see we have the syngraphte here we have the Jeep and if I were to collapse this here can see right now we have this prototype and this prototype, we have this one, all of these this geometry that actually has the name attribute, and we have this transform. So basically, if we go into this import definition, and here we have the option for the pack primitive, let's enable this. And right now it is using the native instances, which mean that the Houdini will going to import the mesh in the prototype, and then it can add this transform to actually place your model. Let's say if we have these multiple instances, then it will just use this transform. But in our case, because we only have a single Jeep model, we do not have any multiple copies. So we do not need to create this as an A native instances, but we can just create the create transform. So let's click on it. Let's go into the scene graph tree, and now here you can see we do not have prototype that is gone, we are only left with transform. And that way, it will be very lightweight to actually work with, and it will be easier to actually assign the material as well. And with that being imported, let's add another sub import node. And this time, I'm going to import my terrain. So let's click on this out terrain, and I'm going to just rename them accordingly. Let's rename this train. Let's duplicate this soap import node, and let's import. Let's see what do we have? We have this one, the gross. So maybe let's import the gross after the train. So let's rename this to our gross and let me duplicate this again. And let me pick up my selection. We have the outcross. The height field is actually the volume representation of our terrain, so we actually do not need this height field because we already have our terrain. And now let's import the out mud. And I'm going to rename this to mud as well. Let me duplicate this again. And let's see what. Let's maybe import these rocks. Let's rename them accordingly. Rocks. Let me click and present all to duplicate. And rain we already have we need the water. So that will be our water mesh. And now we need the Word inward interior. Out water interior, that is actually the volume. So let's hit except, and we just need to type this from water interior. And we are going to use the volume shader to actually create the water interior. Now that we have all of these imported, I'm going to maybe select all of them, and let's go into the layout. Let's distribute these nodes horizontally. And that we have even spacing between them. And now let's add an A merge at the end. Let me select all of them and merge them together. Let's view the result, and here Houdini will import all of our assets in the Solaris context. Let me activate my camera view tool, and here as you can see. We have our assets imported. And now let's create an A light in here. So I'm going to add a dome light, and I'm going to just connect this after that and to the dome light. Let's go into the base properties and let's add the HDRI that we actually downloaded. So that is actually I think in the Geofolder, let me see where I placed it. So it's not in here. I think it should be let me see where I placed that. Okay, so I actually forgot to extract my HDRI. So I have extracted my DRI in this project folder. So now we can go into this folder, this texture, and let's pick up our HDRI. And here I am placing my HDRI into the root folder of this project folder. So let's load this a horn stage under square two K, and accept. And we do not need to adjust any of these properties. The default is fine. Let's view the dom light. And here as you can see we have our dome light imported. And if you don't want to see the dome light in your put background, I can just click on this ie button, and we just need to go into the background, and we just need to uncheck this display environment light background, and now we should not see the environment light. Let me close this window in here, and maybe while we are here, let's change the color scheme to dark as well. And maybe let's see dark gray. Okay, dark gray is fine. Now, I just need to pick up the camera angle that I want. Let's create a camera in here. So I'm onto the new came. Let's click on this and let's click the new camera button to create the camera at the current view. I'm going to enable my view, this camera view tool and lock button is on now, which means that I can just start placing my camera where I would like. Well, maybe let's place it like that. And let's click on this log button to unlock this. That way we can freely move around, and we have this camera position. And if we like to view this through the camera, I can just click on this Snow Cam and click on this camera one. And that way we are back with the camera. And after that, let's add an Karma setup node to actually set up our Karma render settings. And here we have this one. Here is a tip pre compile render kernels. That is fine. We can just click on this. That is our input stage, and I'm going to just view the Kerma render setting that way when we are going to use this one Karma XPU Houdini will going to use this Kerma render settings. Let's go to the Karma render settings and in here, we can define the resolution. So let me change the resolution to an full HD resolution. So let me pick the preset 1920 by 1080, the HD resolution and the engine, we are right now using the CPU as our render. Let's change this to XPU. We are going to use the XPU because it will be very fast for rendering. And now we are ready to create our materials. And for that, I'm going to create a material library in here and connect this. And now let's dive inside, and in here, let's start creating our materials. Let's do that in the next lesson. 18. 18 Shading Jeep Model: Okay, let's start creating our materials. And first, let's create the material for our Jeep. And if we go into the scene graph tree and take a look, here as you can see on the Jeep, we have the material for our wheels. We have the back, left, front, right, and we also have the body. And if we were to collapse this, and here as you can see, we have material for our body, the other that we have the front glass, headlight, panels, panel glass, and seats. So all of these different materials that we actually do need to create. So let's start with first creating this one material that will be for our main body. So in here, I'm going to just right click in the material library node. Let's go into the Karma, and let's add an A Karma material builder. And let's add this in here and I'm going to rename this material to be our body, and let's dive inside. And in here, we have the material X. Let me remove the inputs as well as all of these displacement and these we do not need them. And for the body, I'm just going to use the base color only. So for that, I'm going to import the material lacks image node to actually import our material. So let's add this. And onto the file name, I'm going to just pick up my material. Let's go into the Geo and onto our Ville jeep, let's go into this folder, and here we have this cheap base color. Let's hit Accept, and we just need to connect this onto our base color. So I'm going to connect this onto the base color and we are just going to use this as an A, our body material. We do not need to create any more complex material than that. And after that, let's maybe create an A material for our wheels. So let's add another Karma material builder, and I'm going to call this one to be wheel. And by the way, if we collapse, this wheel or this node transform node, as you can see, we have these two different objects. We have the tire and we have the wheel. The tire will going to be the rubber part of our wheel and where it says, wheel actually the rim and all of these meta like parts. So we actually need to create these two different materials for this whole wheel. So for that, first, I'm going to create the material for our tire, and that will be this rubber piece. And let's duplicate this again. And this one, I'm going to rename this wheel because that's what it says. It says wheel. So we have the tire and wheel. Let's dive inside the tire. As always, let's remove all of these displacement and these nodes. And this time, let's use the PBR texture set. We have this one material PBR texture set node. Let's add this. And in here, we can actually define our base color metalness all of the PBR maps in here and that way, it will be easier to import all of them. So let's start with the base color. Let me pick this base color, and here, let's start with our Let me see here we have the spare tire. Let me scroll down. Okay, here I can find the tire base color. Let's add this and we have the metalness and the specular roughness. Let's maybe add this one because we do need this roughness map. Scroll down, here we have this tire metallic roughness. Let's head accept, and now we need to go into our bump map. And here we are using the normal map. The normal maps are provided. So onto the bump style, let's change this to normal, and I'm going to just increase the scale to one. And in here, we need to define the normal map. Hit Let's click on this button and choose this tire normal. Let me find. We have the tools, and we have the toy normal headapp and now we are done. Let's go into the base color and let's connect this onto the base color slot, and we have the specular roughness. Or let's click on it and click on this with this specular roughness slot. And lastly, we have the normal. So let's click on this normal, going into the geometry section of the materials, material X. Let's click on this normal to actually add the normal. And with that, this tire material is done. Let's go into the wheel, and I'm going to just delete all of them. Let's add another material X BR and onto this one, this base color, we need to do the same thing for the wheel. Let me find, here we have the wheel base color. I'll accept specular roughness. Let me find the heel metallic roughness. And let's go into the bump. Let's change this to normal, change the scale to one to the normal map. Let me scroll down here we have heel normal. Now let's start plugging them base color to our base color, the specular roughness to our specular and specular roughness lot. The normal let's go into the geometry and onto the normal input. Let's go back. We have finished our tire and wheel, and maybe let's duplicate this heel node. And that way we have all of the PBR set and all of these things connected. Now we just need to rename this. And for this one, I'm going to rename this maybe headlight. Let's create a material for headlight. Let's dive inside, and we just need to replace this in here. So onto the bump map, let's go into the normal and let me find the headlight here we have headlight, normal, it accept. Let's go into the texture and base color. Let's find the headlight, base color, let me find the headlight metal like roughness. Accept. Let's go back. Let's create another material, and let me see. Let's go into the scene graph tree. So we have created materials for our wheel. We have the body. We have the headlight, and let's create the material for the seeds. So I'm going to rename this one sets. Let's dive inside. And let's start with the base color. Let's click on this and we should see the seeds base color. Here we have it except. Let's go into the specular roughness. Let me find the seeds metallic roughness. Let's hit accept. Let's go into the bomb and onto the normal, let me find the seeds normal and hit accept. Let's go back and let me duplicate this again. And this time, we are going to create the material for our let me see this one, the sideline. So let's rename this two sidelight. And let's dive inside. Of this node and onto the normal map, let me find the side light node. We have this one, the seed seeds side headlight. So we only get the base color for the sidelight. We do not have any maps. So maybe let's remove this normal map, and let's remove the specular roughness. Let's click on this base color. And side head light base color, except, let's remove all of these wires. So let's select the wire tilt, select this wire antilt because we only have the base color, so let's connect the base color only. Let's go back. And now let's create the material for our front glass. And I'm going to create very simple material. So let me sorry, go back, first, rename this to our glass. Let's dive inside. Let me remove all of them. And for the glass, I'm going to just use a very darkish color. I'm going to maybe let's use this an A 0.2 value of gray. Let's go into the specular. That is all the way up to one. We just need to lower down the roughness to create an a full reflective material. So let's zero out the roughness. And that way we have this darkish glass looking glass material, and that will be fine. And we also have some material for the tools and the panel. And these are for the interior. Hers can see we have material for this interior. But since our camera angle will going to be like this, we actually do not need to create the additional material for the interior. So these materials are just fine. So let's go back and let's start assigning these material. So let's go into the material ibrary onto this scene level and in here, I'm going to create an A material linker node to actually link these material onto geometry. Let's add an A material link node. Let's connect this in between if we were to enable the parameter of the material linker and here can see we have the materials that we actually created. Have the body, glass, and all of them. So these are for our Jeep. So let me expand this one. Here we have the jump try tree that is our Jeep. Let me collapse this. And here we have the wheel. Let me collapse this in here. And I'm going to assign this. Let me see the tire material onto the tire and the wheel to the wheel Okay, so here I have assigned all of the material onto these wheels. Basically, I just click the tire and drag all of the tire onto the tire and wheel onto the wheel. So the tire material is done. Now we need to collapse this wheel. And now we are in the body. Let's assign the material for the body. Here, we have the body. Let's assign this onto the body of the jeep, and let's also assign the material for this glass. So the glass will go into our panel glass front. So let me track this in here. Onto the panel, that is the I think that was for the front panel, but we actually need to set this on toward this front glass. That is our front glass. So let me add this in here, and here as you can see now we have added. Now let's go into the headlight and let me find. Here we have the headlight, that is the side headlight, and we should see the front headlight. Headlight headlight headlight, that is the front headlight. So let's click on this headlight that is for. These guys, can see, we have the material. Now let's assign onto this side headlight and here we have the sidelight. Let's click and drag onto this one. And here we have the material for our sidelight. Now let's add the material to the sets. Let's click and add this onto the seats. And we have that. And with that, this Jeep has been finished. Our material has been added. Now let me collapse this window, maybe make this window a bit smaller. Let me press the PK to hide this. Now, let's go into the material library again and let's start creating our more material for this whole project. 19. 19 Shading Terrain: Let's create the material for this terrain. I'm in the material Library, and in here, let's create an Karma material builder, and I'm going to rename this to our terrain and let's dive inside, and I'm going to delete all of these inputs, the displacement, and we are going to use these two different materials. Remember, we have created the mask where we have these tracks and onto the interior onto where we have water flowing and onto the side. So let's see how we can actually create these two different materials. First, I'm going to import all of this texture, and for that, I'm going to create an A material X PBR textured set node, and onto the texture set node, let's enable the parameter. Let's start creating our material onto the base color. I'm going to let's go back and let me fine. Let's go into the first one, forest ground. Let's click on it. And here we have the diffuse that will be our base color. Hit Accept, and let's go into the specular roughness. Let's pick up our forest ground roughness. And let me, okay, we have the roughness, head accept. Let's go into the bump map. Es change these two normal, change the value of this one, two, one. Onto the normal. Let's see, we have the forest ground normal. Let's head accept. And now, we need to create another material. So first, maybe let me connect all of them. So let's connect the base color to the base color and the specular roughness onto the specular roughness lot and the normal to our geometry and normal load. And because I know that we are adding this onto our terrain, so we do need to actually tile our material. And for that, we need to create the texture coordinate, and we actually have the Us to actually import the Us. We have this one, here we have the material texture coordinates. Let's add this. And if I were to enable here, we have this one but vector two, which means that U is a vector two. So that node will actually bring up our Us in our Solaris context. And we can actually connect this like so, and that way, we are importing the UVs and connecting them in here and we are nothing actually adding that. So to actually create the repetition, we can add the multiply node in here. So let's add material X, multiply node. Let's connect this in between. And now, we can actually multiply the X and Y, the U and V to actually create the tiling because I want to scale out my tiling in both on on the the same way. So I'm going to just double click and just click and drag onto there and just click on this relative channel reference, which means that I can just type the two and this one will be linked. So that way, we can actually create the repetition equally on both and, and that is fine. Not right now we are only using the tiling of the value of two, so let's keep it like that. We can change this later. And now we just need to duplicate all of our setup. That is our material, and these are our texture because we are going to use these two different materials. So let's duplicate all of the setup by selecting all of them, press and hold the Alt key and drag. That way we have another this material. Let's go into this one and just replace this texture set from forest ground to let me go back this brown mud leaves. Let's click on it, and first, we need to define the diffuse. Head accept and now let me go back and brown mud leaves and we need the roughness, head accept. Now finally, we need to define the normal, let's double click and let's go into the brown mud leaves, and we have the brown mud leaves normal and text set. And now we just need to blend both of these material, and we can do that by adding the material X mix node. So here we have the material X mix. Let's add this and here we can define the foreground and the background material. And now we can use the mix to actually mix both of them. And to actually mixing, we can import the mask that we actually painted previously. And to import this, let's add our material X image node. So let me find here we have material X image, and we just need to open up our mask. So double click, double click on it, I think that was in this folder, here we have the mask. Let it accept and the signature is color. So maybe let's change this to float because that is an A floating point value, we only care about this black and white, so that is not color value. So let's change this to float, and I'm going to connect this onto the mix. And that will be our material out. So I'm going to connect this one onto this one. That will be our output. And let's go back onto our lop N. Let's go into the material linker and let's find where we have terrain. Here we have terrain material, and now let's assign this onto our terrain geometry. Here we have it. And now, heros can see we have our material, and that is working fine. Where we have the mask, hers can see, I can see the different material, and that is working well and good. So let's start creating different materials. So in the next lesson, let's create the material for our Mud. So let's do that in the next lesson. 20. 20 Shading Mud: Let's create the material for this Mud mesh. So let's dive inside the material Library, and I'm going to create an Karma material builder. Here we have the Karma material builder. Let's add this node in here and I'm going to rename this one to be our ud. And now let's dive inside this material and just intelet all of them. And we actually need to connect this into our out. And let's add the material X PBR node to actually import all of our maps. So let's add this. And onto the base color, let's go. And we are going to be using this one, this brown mud leaves. So let's add an diffuse. Here we have brown mud leaves diffuse. Let's add this. That will be our base color and the specular roughness. Let's click on it, and we have let me find the roughness. Here we have the roughness, head except. Let's go into the bump. Let's change these two normal, set the scale to one onto the normal, let me find bump normal. Here we have it. Head except. And now we just need to connect these maps. So let's change the base color to base color and let me find the specular roughness, the specular roughness to specular and specular roughness. And lastly, normal onto our geometry normal. And right now onto this material set, if we enable the parameter, hers can see we have the projection type. Right now we are using the UV projection, which means that Houdini is looking for the UVs to actually project our maps, but we do not have UVs on our mash. Instead, we are going to use the triplanar projection. And for that, let's change the projection type from UV to triplanar. At this, and here you can see, we can start to see these maps applied, but right now they are stretching. So let's add the rest position that we had just created previously. So we are going to use this one. Here we have the position for the triplanar. So let's import this and to import this, we can add the USD prim war reader. Sorry, not the UV texture. I accidentally added the wrong node. Let's add an USD primar reader node. This one, let's set this and we just need to set the name, the attribute that we want to import, and that is called the rest. That is the rest attribute, and that is an a position. So let's change the signature from flow to let me say vector. Be position is a vector, let's change this to vector. Now we can just connect this onto our triplanar position. And we should see, okay, right now, it's still stretching, and I think we need to actually control the tiling for this triplanar and to actually control the tiling, we can add the multiply node. So let's add material X multiply, let's connect this. And let me connect this. Okay, that is input one. And right now we are using the tiling value of one in all xs so maybe let's link all of these parameter because later it will be going to be easy to adjust the tiling, and we just need to adjust this input one and all of them will going to be adjusted accordingly. So now let's see how the tiling of this material actually looks like. So let's change the render engine to Karma XPU. Okay. And here you can see how this material is working, but I think the tiling is a bit too high. So I'm going to let's go into the material X, multiply, and let's lower down the tiling value because right now our texture is actually repeating a lot. So I'm going to change the value to an A value of 0.3 maybe to a very low value. And I think that this repetition is looking good. So let's keep it at the value of 0.3. And maybe let's adjust the tiling of this ground material, this rain material as well because right now, I think that this ground material has the less tiling. So let's increase the tiling value. So I'm going to change this one to 50 wiki again. So let's go back onto our terrain, and I'm going to go into this material X multiply and enable the parameter. And right now we are choosing the tiling two by two. So maybe let's increase the two, three by three. And since we are going to use the tiling for both of them, so maybe we just need to connect this onto the texture coordinate of this texture set and that way, we will only need to just adjust the multiplication in here and that way, both of the tiling will going to be controlled from here. Now, let's see the result again. Let's click on this Karma XPU. Okay, so I think that this tiling value is looking fine. But this the first material that this one it's actually looking a bit lighter to me. So maybe let's bring in our ambiden collusion and let's also let's multiply the base color with the ambide collusion that actually came with the material. So let me see that is the forest ground. So want to adjust the material for the forest crown. So let me first, let's maybe change this to dik VK, and let's go into the clusion and bring up our embonclusion. So let's go back and we need to go into the forest crown. Let's go back forest crown. And the abon clusion is actually in the arm. So it has three maps. A, the first one is the bonclusion R is the roughness and M is the four metallic. So let's add the arm in here. And now if we take a look, this one, occlusion. So it will output the very first input. So the very first is the embed clusion. So that is actually the map that we are interested in. So let's add a multiply node in here and let's multiply our base color with the embed clusion. Let's add this to a collusion, and that should be our base color. And let's see how this looks like. Let me change this to Karma XPU again. Okay, it's looking much better now. By adding the ambien occlusion, I think it looking good now. So let me change this back to Houdini wiki again, and now we just need to bring in the wet maps for our mud. Right now, as you can see, we are not actually importing the wet maps. Let me go back and let's go into the mud material in here and let's bring the wet map to actually adjust the wetness of this color. And for that, we are going to adjust the roughness. And where we have the let's say, or this mud is actually touching the water, I want this to be very reflective because when the material gets wet, it gets shiny. So we can adjust the shinness by use adjusting the specular roughness. So let's import first import the wet attribute. So for that, I'm going to add the USD prime war reader, and in here, I'm going to type the attribute name, and that is called the wet, and it is an A float. So let's keep it like that. Now we just need to multiply this with our roughness. And where we have this, I know that this range is in zero and one, so that is good. Let's change these two in here. And I'm going to connect the specular roughness as an A multiplier. Sorry, not this, the specular roughness. Let me connect this, and that should be our new specular roughness. Let me add this. And where we have the value of zero, we will get roughness value of zero, and where we have the one, we will get the full roughness that is actually coming from this map. And we also need to adjust the base color. I want to create the base color darker, where we have our wet mud. So for that, we need to create the we need to multiply our base color for the darkish color. And for that, I'm going to create the constant node in here. So let's add constant. Sorry, not this constant, but that should be called the material X constant. Material X constant. Let's add this. And signature, let's change this to color. And I'm going to say where we have the value of zero. I'm going to where we have the value of one. I want to change the value to all the way up to one, which means the full base color. And let's create another this node. And where we have the wet map, I want to create a slightly darkish color. So maybe let's change this to a value of 0.6 maybe. And that way, we will get a Tarkish looking result. And we can actually mix these together. So let's add a material X mix node. Let me find material X mix. That is the foreground, that is the background. Let me see where does it go? Okay, I'll connect this and let's use the wet as an A mixing value. And now we just need to multiply our base color with this value. Let's add an material X multiply node again. Let's multiply this with our base color, and that should be our new base color. Let's connect on the spas and base color. And now, heres can see let's say if I were to maybe let's disconnect this specular node. And maybe maybe for now, let's only use this material mix none, and I'm going to use the base and base color. And I cannot see it correctly. Let's change this to black. Okay, now I can see. And here you can see right now the values are reverse. So basically, where we have the wet, it's getting the white and where we do not have wet, the values are zero. So we need the opposite of that. So we can actually fix this very easily by adding the material invert none. So let's type the material X invert. Let's invert the incoming values. So I'm going to just connect both of them to our out. That is the out and for the in this one. Okay, now s can see how these values are correct. So where we have the wet, it's getting the black, and where we have the dry, it's getting the white, and that is correct. Now, we can just connect this one into our base color. Let's bring this roughness back. Let me connect this one to our specular and specular roughness. And right now we are using the full black. That is why the base color is getting this full blackish. So let's go into the material X, and let's not use the full black, but change the value of 0.5 to create the darkish color or maybe 0.6. Let me see. Slightly increase that. Okay, so that way, we will have the feeling that this mud is actually wet. Now, let's see the result, how it looks like. Let's change this to Karma XPU. And if I zoom in, let me zoom in on it. And here you will see that we have this wet map working. And as you can see, we have this transition between the dry as well as this wet looking mud. And now in the next lesson, let's create the material for our water. 21. 21 Shading Water: Let's create the material for our water, and I'm going to create the material X. Let's go to the Karma material builder, and this one, I'm going to type the water. Now let's dug inside. Let me delete this and delete both of them. Now onto the base color. We actually do not need any of these maps because this is going to be a very simple material because it's going to be a transparent. We do not need any base color, so I'm going to just zero out the base, add on to the specular and actually, I'm going to zero out the roughness because we do not need the roughness in our water. So let's change the roughness to zero, and let's keep this specular all the way up to one. And on the index of refraction, let's adjust this. The index of refraction of water is 1.33, let's add this. And let's go into the transmission, and this one will going to be a fully transparent material. So let's enable the transmission to all the way up to one. And with that this water material is finished, and now we need the material for the interior of our water, and we are going to use the uniform volume for that. So let's click on it. Let's go into the Kerma and onto the pyro. Let's add the Karma uniform volume material. Let's add this. And I'm going to call this one the water interior. And now let's dive inside. Here we have the Karma pyro shader. That is an volume shader because we are going to be using our density volume that we have created to create the interior of our volume. And here we can adjust the density and we can adjust the smoke color. So maybe let's create a muddy looking smoke color. Let's maybe create more light light and let's desaturate it a bit. And we can play around with this later, and that will just give us the interior color. I think that looking fine. I'm going to just close this window, and I know that we need to increase the density because right now, this will be will going to have a very low effect. To actually add the depth, we need to increase the density. So let's start this in a value of ten maybe now let's go back to this one. Let me hide the parameter of this onto the Solaris lever. Let's go into the material linker, and let's assign this. And we need to assign. Let me see. Let me collapse this window a bit bigger, make this a bit bigger, and we have the material for water and the water interior. So let me find the water. So that is our material for water, and let's use the water interior on the water interior section. Now let's see the result how it looks like. Let's change this to Karma XPU again. Okay. And here as can see we have our water, and right now this water looking like an rea in water. So we can actually play around with the material. So let's go into the material library, add on to the water interior. We can just adjust the color. So maybe let's create more darkish color. Let's play around with this value. Let's create even more darkish. Let's keep adjusting this to our liking. And here you can see by playing around with the color, we can actually adjust the color of this water interior. And with that, this water material is done. So now in the next lesson, let's create the material for our rocks and grass. These are the final materials. So let's do that in the next lesson. 22. 22 Shading Rocks And Grass: Let's create these two last material, the material for our rock, as well as these grass. So let's dive inside the material library node, and I'm going to create the Karma material builder, and I'm going to name this one rock. First, I'm going to add the rock material. So let's dive inside this one. And delete maybe these two nodes. Delete this one to. Let's add the PBR map node, this one, material BBR. And let's start bringing our map onto the base color. Let me go into our back, and we have this one rock mouse set. Let's go into the folder. We have the diffuse. Let's add this and the roughness. Have this roughness, the last one, and we have the normal. Let's go into the bump. Let's change this to normal, change the scale to one onto the normal map. Rock more sat normal. Here we have it. Now, just connect them base to our base color, our roughness to specular roughness, and lastly, normal to the gem to normal. Let's go back and maybe I'm going to just duplicate this node. And this one let's create the material for our grass. So let's rename this to grass. Let's dive inside, and we just need to replace these maps. Let's go into the normal map, start with that. Let's double click to Goba and let's go into the grass medium, and let's add this normal decept. Let's go into the texture and let's play around with the base color. Let's click on this to go back, gross medium, and let's bring up the diffuse. At the roughness, let's go back the cross medium texture or you have this one, the roughness. I'll accept now we need to go back onto the Solaris level. Let's go into the material linker and let's start assigning them. First, we have the rock. So here we have the rock geometry. So let's click and drag onto the rock. And here we have our rock material that is working. Let's go into the grass and let me find grass. Here we have grass. Let's add this, let's see. Okay, our grass material is working fine now. Now, let's see how it looks like. Let's go into the perspective change to Karma XPU. Okay, here as you can see our grass material is working, but we are actually not using the opacity, the Alpha mab that actually came with it. That is why it's actually not looking right. We have these funny looking grass blades, and that is because we are not actually importing the opacity. And to actually import the opacities onto the grass, we are not going to use onto the material level. So let me unclick and let's dive inside the material library. Let's go into the grass. And here you will see onto our geometry, we have the option for the opacity. We can add the map to actually adjust the opacity. But by doing so, it will going to be very hard on the rendering, so it will be very slow to render and to actually add the Alpha maps onto all of these instances very efficiently, we have a new way. So let's go into the lop net back where we have imported our grass. Let me find here we have the grass. So there we have the grass, and I'm going to add the render geometry setting in here. So let's add geometry settings, and let's connect this into the grass and let's open up the parameter, and in here, we can adjust all of the different settings for our render geometry. But we want to go into the shading tab and here we have the new option to add the stencil map. So right now it is grade out, so let's click on this button, and let's click on this set or create option to actually enable this tensil map. And we are going to use the OPASiT map in here onto this tensil map to actually cutter out our mesh where we have the black and white mask. So let's go into this tensil map, and let's find onto our cross. So here we have the cross medium Alpha. So let's add this. And by doing so, now we will going to be cutting off or mesh and it will be very fast. Let's render this again and with the result Okay, to maybe actually better view this, let's zoom in into our grass to see if that is actually working. Okay. So here you can see right now, it's actually still not working. So maybe let's click on this tensil threshold. Let's enable this to set or create, and that way we can adjust this tensil threshold and let's render it again. Okay. I can I can still see that this mask is actually not being working, so let's maybe adjust the stencil threshold and a value of one. Let's see the result again. Okay, still not working, so maybe let's refresh this. Let's go into the Houdini and I'm going to let's see that if we are working on the grads. Okay, so that is the grass. We are adding this. Let's see why it's not working properly then. So let's see Karma render settings. Okay. Let's render this again and view the result. Okay, it's still not working, so maybe let's change this to ten k. Let's go in here. The threshold, I think it should suppose to go into the zero. Let me click on this and let me see that if we are actually working on the correct map. So gross medium texture, Alpha. Let's check this again, roughness. Alpha. That is the correct mask, so it should supposed to work. Maybe we need to refresh this again. Let's click on this Karma XPU and let's try rendering this again to see. Okay, it's still not working. So maybe let me close and reopen my project file to see that it's actually working or not. Maybe we are getting the cache. So the cache is actually causing the problem. Let's see. I'm going to change this two k and let me reopen this scene again. Okay, I have reopened the scene and it still does not seem to be working. So let me change this back to DNIVK and let's see what seems to be the problem. Let's go into the Sab Import node, and let's view this. Let's go into the primitive definition. And right now onto the pack primitive, I think, let's see what we are using. So if I were to go into the new pen tab and let me enable the Solaris scene graph tree, let's see the grass. And here as you can see we are using the prototype and Houdini is creating this transform, so it is not very efficient. So maybe let's click on these packed instances and right now we are creating the native instances. Let's click on this point instancor. This point instancor will going to be very fast because we are only going to be importing the variation, the A, B, CDE, all of these variation, and then Houdini will going to be using these actually transform to actually create these instances. This one will going to be way more efficient. So maybe let's see if that point instancors actually fix the problem. So let's go into the scene view again and I'm going to render it one more time. Let's change this to paramyx I think that fixes the problem. Now I can see that the stencil map is actually working. Okay. So let me select my camera. So let's click on this camera to view through our reserve. And right now, the grass location is not correct. So let me first disable this grid. And to actually fix this, we can actually go back onto the soup level and let's paint some of the area back to create more gross. I'm going to just change this to ten Wk again. Let's go back onto our mud effects. Let me see where we are creating the grass. We are creating the grass in here, we have the texture mask paint. Let me view this, select these node and hit except press Enter to actually view it manipulator. Maybe let's start painting, adding some of the more of area. So I'm going to add the grass in hair as well. Let's start painting this and maybe let's paint this area as well, and something like that. And now let's go back. We can actually go back onto our lop net and see how this actually looking, and here can see we have the live update. Let me change this to Karma XPU again. Let's see. Okay, so now I think the grass is looking fine. So at this point, we are actually ready to render out our effect. So I'm going to just let me go onto my Karma render setting. And let me make this wind pane a bit bigger. Onto the output picture, I'm going to select the location, and I'm going to select this onto the dollar sign job and onto the render folder. I'm going to call this one render underscore. V one for the Version one. And after that, dollar sign F, which means the current frame number because if we do not add the dollar assign F, we are going to render the animation. So this will going to be overwritten by the next frame because we are going to be using the same name. So if we add the dollar sign F, which means we are going to stepping the current frame number. So we do need the dollar sign F. Now we just need to at the file extension that we want to render, and I want to render the EXR sequences. So let's type dot EXR and hit Accept. Now at this point, we can go into the USD render up, and in here, we have the valid frame range. Right now we're using the current frame. Let's change this to specific frame range. And by doing so, we are going to be rendering our whole sequence, all of these 275 sequences. So let me change this back to Houdini k and now press render to disk option to render out all of your sequences. 23. Conclusion: Okay, all done, I have rendered out all of my sequences, and here is our end result. And here as you can see, I might have adjusted this cross. I have adjust the painted area, as well as I readjusted this painted area where we have these tracks to actually make the tracks a bit bigger. And other than that, I'm using all of these same settings, and also I have adjusted this color of our water and we have all of the settings are the same, and here as can see our Jeep is actually coming into the mud, and in here, it's actually slipping. And after slipping, it actually grips the ground and start to moving. And with that, all of our effect actually come together and I think it's looking good. So that's it with that course, and I will see you next time.