Rony Soussan wrote:If the objects where not imported using hierarchy, and there is no object ID, then you can't.
But the MatID should be there, even if you only had one object.
For example, consider the Cube3D. It's one object, no need for a hierarchy of meshes. But each face has a unique MatID.
Oftentimes 3D meshes will have different materials on the same mesh, especially if there is no reason to duplicate the geometry, like when creases and seams are handled with normal maps instead of actual vertices.