I am using the custom Fracture Blender build for a tree shatter simulation: https://wiki.blender.org/index.php/User:Scorpion81/Fracture_Documentation

Haven't used the physics system in Blender at all, but wanted to see if it was possible to have a physics simulation of a tree shattering and export that as an .abc for import into Unreal Engine. I can run the simulation just fine, but can't figure out how to correctly bake it so that the results are preserved and can be edited in animation/or exported to Alembic.

Does anyone know of a tutorial on how to do this?

Check out the blend file here:


You should just try to export the set up FM simulation via "File->Export->Alembic". Then set your desired frame range and while exporting, the FM simulation is being run in the background and the mesh is dumped out once per frame. That's why the resulting .abc file becomes rather big, 145 MB in this case. And note you will have to re-map the materials manually... only the material assignments are exported / imported, but the values of the material settings AFAIK not (they differ between different programs, this might be the reason.)

I have set up an example blend with a tree fracture scene, derived from your initial blend. In blender you should just need to export this to Alembic. But in case you also want to edit something, it becomes much more tricky IMHO. You could also convert to keyframed objects, but this will mess up the "fixed" normals again (only FM supports this).

Edit: I did not use fixed normals here, because they work better with more regularly divided base geometry, and best with autohide / automerge. But when the simulation runs and the mesh gets hit, you might get temporary artifacts at the splinters. Instead i tried to mimic the behavior with an Edgesplit modifier. The result is not as smooth as the other approach, but is visually "stable".

Here is the example blend:

  • $\begingroup$ Hey man, thanks so much, learned a lot from your blend. My simulation knowledge of blender is very limited, so didn't even realize I had to actually animate the "striking object" I was manually manipulating that. The fracture build of blender is amazing, love it, the finished result looks amazing in Unreal. It complained about some of the meshes (for some reason it couldn't triangulate them) but once I added a triangulate modifier in blender it imported just fine. $\endgroup$ – deranjer Apr 2 '17 at 15:54

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