 Howdy guys. All right. So in this video, what I wanted to do was walk through the new RBD soft solvers that are available in Houdini 18. And I wanted to go and set up a whole sim. So what we're gonna do is we're gonna build this building. We're gonna set up the sim and then we're gonna destroy it. All right. So we're gonna walk through a lot of cool techniques for this stuff. So let's get started. Okay, so to get started here, what I'm gonna do is go and create some sort of building type of structure. So I'm just gonna call this building like so. I just created a geometry node and I'm gonna go and drop down a grid here inside of my building node there. And I'm gonna set the size to something like, let's say 3 by 3. I'm just gonna make something like a simple tower with many floors on it. All right. And I'm gonna go and resample this. That way I can actually go and grab a bunch of sections of this and create walls out of it. So I'm gonna say that, you know, every wall maybe is about two meters. And let's say we're gonna resample by polygon edge like so. Awesome. And we'll leave it all like that. And then the next thing I want to do is we're gonna drop down a convert line node. There we go. And this will then turn this into a bunch of different individual primitives there. All right. Cool. So then I'm gonna do a carve here really quick. And I'm gonna do my equal offset trick. All right. So I'm gonna go and copy the first U, paste it into the second U as a relative reference. And we're gonna do one minus. This way I get an equal offset on both sides of my individual segments there. Cool. So with that, let's drop down a new sweep node here. All right. And we're gonna utilize the ribbon feature for this because I'm basically gonna build the bases for these walls here. Awesome. And then with that, let's go and drop down a copy to transform node. And let's just move these guys up. Let's say three. Actually, let's do two. And why? And we'll make a bunch of copies for this. Do something like, yeah, five copies is fine. Then let's drop down a skin node and we'll skin that together so we actually have some geometry. So we're gonna have to actually utilize the skip every nth point and just get this guy situated until we are good. All right. So now we got a bunch of walls. Let's go and create the individual floors now. So what I'm going to do is branch off over here. And we're going to do a poly extrude. All right. There we go. I'm going to hit shift s on the keyboard to get a different wire look. And then I'm going to go and just lift this guy up. So this is going to become my floor. All right. I'm going to make sure to output the back. So we're going to fracture this with the material fracture node. And so we want solid objects for the most part. All right. Very cool. So before I get too far, let's make sure that we actually cap these guys as well. You can see we have open ends there. So let's drop down a poly cap node. Like so. And we'll just cap all those guys off again. So we have solid pieces of geometry. All right. So let's copy this copy and transform node. And I'm going to wire that into this guy right here to create all of my floors. All right. With that we can now merge these two guys. So I'm just going to hold down alt on the keyboard, hover over my output and then just left click and drag to create a merge node. Just to see how things are coming along. All right. It might be kind of nice too. It also has some horizontal structures on the outside there. So let's go and actually let's redo that again. So let's merge this guy again. There we go. Let's go and copy this guy. And let's pull off from the grid again. All right. And then let's use a sweep node for this. Awesome. And we're going to set this to a surfer shape of a square tube. And then I'm just going to put the columns down like so. And then we'll output this guy into that same merge node there. Awesome. Let's make it a little bit bigger. Cool. Yeah. So now we're starting to get a nice little building. Now we just need some pillars for the outsides there. That is looking pretty cool so far. So this is relatively easy as well. So what we're going to do is we're going to need to get this guy because this is where all the points are. So I can go and copy a grid to this as well. So let's do that. We're going to do a grid. And let's make a little bit of space for ourselves over here. And I'm going to drop down a copy to points. And we're going to wire that in for the first input, not for the second input. And let's go and set this to one and one for the size. Let's put it also onto the xy plane. And put in two and two for the rows and columns. And while we're at it, let's just hook this guy up because I just want these guys to be square. And then I'm going to make them just a little bit smaller. Awesome. So now all I need to do is just extrude these guys up. So we'll say poly extrude. And we will extrude it up by two. And we need to make sure we reverse this guy up here. There we go. And let's output the back. So we have a closed shape. And then we can utilize our copy and transform node to make a bunch of copies of those guys. And then we'll basically merge that in. There we go. We just need to make sure we don't do the last one. So let's just do four for this guy. Awesome. So now we got a building that we can destroy. Cool. All right. So the process for this is to first just go and set up a material fracture node. So an RBD material fracture node. We're going to take our whole building here and just pump that right into that first input. And what I'm going to do is leave it on the concrete type. You can more than welcome to try out these other ones. Just keep in mind that the wood material type will take quite a while to process. All right. So let's take a look at the results here. Sweet. So we got, you know, a nice fractured piece of geometry. And we want to go and destroy all this stuff. But before we do, I want to go and also turn on my chipping here and just walk through some of these particular features of this. Awesome. So basically what it's doing is it's creating these little chip pieces. So we can actually increase this to something like 0.8. And I don't add even more chips. And we can also do the corner depth. So if we do something like 0.1, we'll get bigger chips. And this is really cool for these types of simulations because it basically are these little chunks that, you know, start to break away from these larger chunks. Makes it look just more realistic. Yeah. All right. So I think we're going to go with that. Okay. So the next step to get this rolling is to drop down an RBD bullet solver. Awesome. And what we want to do inside of this RBD bullet solver is turn on the ground right off the bat. That way we have something to collide with. So I'm going to turn on the ground. We're good to go. If I actually hit play right now, we will get this guy falling to the ground. Awesome. Look at that. Pretty quick to get a really nice simulation set up, but it goes even further. And what I'm going to do is show you guys a little bit about the constraints before I close out this particular video. All right. So let's stop that and let's go and wire in this little pink dot right here. That's the constraints that the material fracture node is actually creating for us. All right. And if we were to actually go down and drop down an RBD explode node, where are you? Let me actually type. There it is. Exploded view. All right. So if we were to actually pump the geometry and the constraints into this exploded view and turn that on and then check on show constraints, you can see these are all the constraints. So they're little wires. Think of them as like glue that's holding all these pieces together. And they all have different, you know, strengths. So if I were to actually go and turn on the constraint strengths, you can see that we have these values from blue to red and the differences in their strength and their bond to one another. All right. So with that, let's take a look at our simulation now. Okay. And I don't need that guy on anymore. Cool. So now I've got the constraints all hooked up. Let's hit play and you could see the building is not doing anything. Well, why is that? Well, currently, if we go back to our material fracture node and we go into the constraints tab, our primary strength currently is set to 10,000. And that's really strong. So let's set this to something like 1000 and see what happens. Let's go back to the beginning of the timeline, hit play. And we're still getting pretty strong values. All right. So let's go and put this down to something like 400. All right. We're still sticking. And that is because we are utilizing currently the chipping features and the chipping glue strength is pretty high right now too. So let's set that one down to like 100. And that'll just make it so the chips will fall out first. All right. So let's hit play and we're still not getting anything in this because we need to go and turn on this fracture per piece. So I'm going to set my timeline back to one and turn on fracture per piece. All right. So with that all set up, let's hit play after it's finished calculating here, which, you know, the more you let your fracture, the longer it's going to take for these simulations to get done. But that's why I'm keeping it relatively simple. All right. So there we go. We're rolling. So you notice now that the chips are going to fall out first. So if we were to zoom in here a little bit, so the little chips are falling out of the building first. And once it starts to lose more of its structural integrity, because we have the primary strength set to 400, the rest of the building will start to fall as well. So I'll let this roll here for a second longer. See if we can't get the building to fall. Looks like it's starting to buckle a little bit over here. And there we go. So finally, enough chips fell out of the building. And now the whole thing is just coming down. Very cool. All right. So hopefully that clears things up with the constraints and just how to start to work with them and start to adjust it for the look that you're going for, for the building. The last thing I want to show is how you can add a custom force to this. So like what let's say I want to, you know, have an explosion at the bottom of the building down here. So let's just say maybe right over here, what I need to do is I need to come over here and I'm going to drop down a group node. And I'm going to take in the proxy geometry that's coming out of the material fracture. So that's that third output right there. And I'm going to call this the blast points like so. All right. And I'm going to set the group type to points. Very cool. And we're going to go and we are going to turn off our base group and go to keep it within bounding regions. And I'm going to set it to a bounding sphere. You can use a box as well. I just really want to simulate more of like a, you know, an explosion blast. So let's move this guy out over here because I want all these points to be affected by the initial blast. All right. So we're going to determine an area on our building where the blasts will be affected the most. Basically, you just want to blow away this whole bottom half and just have the building just fall down. All right. So on those points, what I'm going to do is I'm going to drop down a point velocity node like so. Very cool. And we're going to go get this name here for the group. Put that in the group here because this is looking for a point group. All right. And in this case, I want to use the conical noise all right to simulate something like an actual explosion. Awesome. So I'm going to actually drop my direction in y down to point five and make this in one in the z direction. All right. So just reference your little gizmo down here. And then let's set the scale to something like 30. And then what we're going to do is we are going to then pass the output of this into the proxy geometry for our RBD bullet solver node. All right. So let's take a look at that now. So let's go back to the first frame and timeline, hit play. And we should see a big blast down at the bottom of the building right there. Like it just got exploded. Awesome. And so I'm going to let this run just a little bit longer so we can see the full effects. Very cool. And that is how easy it is to set up. So the last thing I want to show when this is all done running through here, I might speed up the video just a little bit. I just get through the sim as I want to show you guys how to cash all this stuff out. So you don't have to actually resim it every single time you want to take a look at it, especially when you want to go to render this out. All right. So I'm going to clamp it out there to 160 frames. Go back one more frame. All right. So let's just put in 160 for here and take a look at that one more time because it's cool. All right. So the next thing that we want to do is we want to drop down a file cache node. Let's do that. All right. So let's go and take the output of our bullet solver and put it into the input of this file cache. And what I want to do is I'm going to hold down control and shift on the keyboard because I want to set my own custom frame range here. We're going to say one to 160 and I'm going to go and pick a folder location. So I have a project currently and I'm going to select the cache folder that I have in there. And I'm going to call this. Let's actually just use this name over here. Well, actually we'll call this BLDG01. And then we need .bgo.sc. And then I'll just put a .$f for the frame number. And with that, all we need to do is go and hit save to disk. And what it'll do is it'll write out the whole simulation to these BGO files. All right. That way we can then, once it's done, it goes pretty quick. We can just hit this little checkbox to load it from disk. And we can come down here to this little button, its little brain, and we can turn off all simulations. But you can see now we still have our building destruction running really fast. There we go. And you can see that dynamic simulation is disabled. All right. So that's how you build a building. Really quick. It's not a fancy building, but it gets the job done. And how we set up a really quick destruction simulation using the new RBD bullet solver node and this material fracture node. And how to actually add our own forces. And then finally how to cache it out to files. All right. Hopefully that helps. Thanks so much.