I'm still working on using Houdini to create Static Fracture Meshes for use with UE4's Dynamic Destruction Mesh (DDM) system. I now have them importing correctly except for one thing. When I use the “Import FBX Chunks” button in the DDM editor, it generates tons of extra material slots. It looks like it's generating one slot per material for every piece. That adds up to a LOT of material slots, to the point that it's really hard to apply materials correctly.

If I import the same file as a static mesh, I get the correct number of material slots.

It looks to me like this might be an Unreal import problem, but at least one post from a staff member at Epic suggested I might have to fix it by changing the way I export the FBX. Here's that post:
https://udn.unrealengine.com/questions/355004/fbx-import-in-destructible-mesh.html [udn.unrealengine.com]

I've also posted about this on UDN, but just in case, do any of you have any idea how to fix this? If we have to fill in 200 material slots on every complex fracture mesh, without knowing which material goes in each slot, it may be prohibitively difficult.

Thanks again for all the help!
Brian

I seem to remember having to deal with this in the past and I'm pretty sure it's on the UE4 side. I haven't found a solution to this on the fbx export.

Mike

Thanks for the info, Mike.

This turned out to be a problem in Unreal. It is supposedly fixed in 4.19.

I'm digging into it right now and I can say 100% sure, that this is bugged now in UE 4.22.1