I'm trying to export an alembic of an RBD Bullet Fracture sim to be textured in Cinema 4D/Octane, with one group of pieces textured with one material, and the other group with another. But when I export the alembic (using rop alembic, and also tried the alembic export function from the file menu) the pieces are just numbered into the thousands, and I can't easily differentiate which pieces should be which material.

I've attached a basic example of the problem. Basically, once the alembic is in C4D/Octane, I need to texture the boxes with one material, and the spheres with another. I've tried using the group node, but I'm still a novice, and could very well be doing things wrong. Any help would be GREATLY appreciated. Thanks so much!

Hi, looking at your primitives I only see a "name" attribute. Have you tried assigning materials in Houdini before export? When I was experimenting with export OBJ/FBX, I noticed it usually works if we have a "shop_materialpath" attribute created.

If you like code, one way is to add a "primitivewrangle" with VEX "s@shop_materialpath = 'MatSpheres';"

Or create path attribute like s@path = /root/`group name`/`piece name`. In alembic enable hierarchy by path attribute.
In C4D just put materials on null objects with group name

Many many thanks to you both for the excellent help! It's much appreciated.