Hi,

I've tried to export a rigid body sim to UE4 with vertex animation export. I got the latest one from the GitHub.

It's a very standard set-up of a pighead being fractured with IsoOffset/Scatter/Voronoi and then I just have it drop onto a ground plane. I export this out, put in all the values into my shader instance and I get this weird jittering going on:

https://www.youtube.com/watch?v=0roKARiRx44 [www.youtube.com]

Also if I try more complex simulations with different meshes and a higher tri count it gets even weirder with pieces floating around in the air.

Is this to be expected because there are just some flaws in the system? Or am I just simply missing something?

Cheers,
Nicolas

Make sure that your texture is set to vectordisplacment and that pixel filtering is set to none.

Mike.

Right, I forgot about that. That fixes it for the pighead. Thank you! If I may add a more general question:

Is there a limit to how much geo / frames this technique can bake / read in the engine error-free? Because I'm trying to push some RBD sims through with higher tri and frame-counts (e.g. 60.000 tris and 512 frames) that also include glue constraints etc. – is this too much to handle for the technique? Has someone done this successfully without getting floating tris? Like a more complex destruction? If so, I must be doing something wrong. My vertex anim kinda freaks out when I get too crazy with my destruction data / the data that I feed in there.

Cheers,
Nico

The rbd export is dependant on number of chunks, not number of polys. You could conceivably have 2048 chunks playing for 2048 frames without too much of an issue.

Problems arise with floating point precision when pieces move very far from their initial position.

That's what I thought. It makes sense aswell considering how the system works. I still get some weirdness happening when I export sims that aren't just the barebones voronoi set-up. However, it's completely possible that I'm doing something wrong. I haven't been working with Houdini for too long.

I'll try posting a scene of one of those cases when I find the time.

I realize this was quite some time ago, but I just noticed I never got back to this. So in case anyone runs into this issue aswell: I recall that I was able to counteract the jittering by changing the scale of the scene.