Join Scott Pagano for an in-depth discussion in this video Apply simulation to full-resolution shell, part of Houdini: Dynamics and Simulation.
- [Instructor] Now our dynamic simulation is setup, we've added everything in, we've handled all of our collision geometry properly, but we've still been looking at the low-res proxy geometry all the way through. So now we're going to look at how we can take the output of the dynamic simulation and apply the low-res motion to the high-res G O. In this video, we're going to look at the shell. So, what we're going to do here, is we had this unpack and create fragments in DOP Import node. And we're going to drag them over here. And what we're going to do is we're going to copy and paste the DOP Import node.
The DOP Import one, if we hit P, look at the parameters, you can see its import style is Fetch Geometry from DOP network. Great, that's the default for this purpose, that's fine. It basically just brings back into your SOP network what happened in DOPs. But what we want for this, under DOP Import two, is we want to switch this to Create Points to Represent Objects. And this is going to create points in space that have attributes on them that determine where those objects are. It's going to give you this error, just don't worry about it. It's got that little warning around it. It doesn't matter for what we're doing.
So now I'm going to use a pretty special node, which is Transform Pieces. And Transform Pieces is going to be able to take this information, 'cause if we run this simulation these points are going to move in space depending on where their objects they're derived from are moving, and we can take that motion and we can apply them at a different geometry. But the key thing is, is that geometry needs to be setup exactly the same as the geometry that these points were derived from. And so we have this Setup Packed Prims node here.
And so what I'm going to do in this Setup Packed Prims node is based on the low-res geometry. So I'm going to copy and I'm going to paste this. And over here under this Blast two we have the high-res geometry. So what I'm going to do there is I'm going to have the second packed prims node underneath the high-res geometry. So you can see again, we have 62 packed fragments, this time in the high-res geometry. So I'm going to feed that into the Transform Pieces node on the left side, and I'm going to feed the output of DOP Import two, which is just bringing in these points, into the middle, which is the template points.
And we're going to look at the output of that. So what we're going to do now, is we're going to run the simulation, and we're going to see the low-res geometry that applied to the high-res simulation. And we'll give it a toggle between them to see how this is working properly. So I'm going to go back up to our top level here, hit my P key to turn off the parameters, let's look through our render cam, and I'm going to hit Play. And, again, we'll fast forward through this, and we'll look at the results together. So we've let this simulation run for the 80 frames and we can see at frame 50 here we have a good view of what's going on.
So now we're going to go back into our shell object and we're going to take a look to ensure that our proxy geometry that's running through the simulation is matching our final high-res geometry that we're transferring that position orientation to. So here, at the end of our Transform Pieces we can see that we have our high-res geometry, which has been packed and fed into there, and then fed with the points coming out of the DOP network. Looks right. So if I click on the DOP Import one node, excellent. So what this is going to show us now, since this is set to a different import style, is this is the low-res proxy geometry that we had fractured up, and that's what's out of the simulation network.
And then on this DOP Import, we're doing the Points to Represent Objects mode, and we're feeding that into Transform Pieces and we're seeing the high-res geometry. So this is a great one-to-one comparison to see how this low-res geometry is coming out of the simulation, and then we're using this Transform Pieces to affect this high-res geometry. So, obviously a couple videos and a couple things we needed to do to get to this point, but this is really fantastic because really straight forward to grab that low-res dynamic simulation output and apply that to high-res geometry.
What we're going to do now is we're going to go back to our master overall view here and the next couple videos, we're going to apply this low-res to high-res transfer system to the rest of the geometry we need to, we're going to tweak a few more simulation settings, and turn on our final textures and lighting, and flipbook this thing out as a nice final result.
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