Cell fracture physics FBX export?

I’ve created a cell-fractured cube and used forces to animate it exploding. Since I want to export it to a game engine (UE4 in this case, but Unity is fine, too) I’ve bakes the sim to motion curves and deleted the particles and forces that created it. So far so good. BUT I can’t seem to figure out the FBX export settings or perhaps what I need to do first in order to get it to export cleanly with animations. Either I get 300 separate pieces, each with an animation and a skeleton that it didn’t have, or I get no animation at all. Is there an efficient way to do this or do I just have to wrangle all 300 pieces into a Blueprint/Prefab to work with them? Any hints much appreciated.


UE4 can only import animation that is’ armatured’ - ie it must have a bone(s) and skinning. Even if the objects are rigid - like say a mechanical contraption - the animation of those parts must be driven from bones. Which is why the FBX option is producing a bone per chunk. The fbx format does not support point cache animation, but UE4 does via the Alembic format. If you’ve baked out your sim you could try exporting as an Alembic. In cases where I’ve needed to simulate cloth in Blender then get the sim into UE4 that is the only method that works. ( be sure to try various settings as the files can get really big).

The other alternative is to let UE4 take care of the exploding physics using its Destructible Mesh workflow, there are plenty of tutorials on Youtube.

Finally, 300 bones is not going to freak out UE4, just be sure that you parent all the bones to a single root bone before exporting to fbx or you’ll get 300 separate animation and mesh files :frowning:


Thanks so much! That solved it! The big thing I’d forgotten to do was parent all the exploding pieces to a null in Blender. That was, as you mentioned, giving me 300 pieces and animations and skeletons to keep track of. The parenting gives me a much more manageable single animation and skeleton. Whew. Thanks again!

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Hi , I know it’s a little late , but can you explain more on your solution. I’ve got the baked animation for each piece , each if those pieces connected to a single central bone when I export. But I still get multiple animations imported instead of one for all.
Thanks for any help :slight_smile: