I saw a few older threads on this, didn't want to necro them so figured would start a new thread.   I am attempting to export out of 3DC a single OBJ with Material IDs/Texture sets defined so I can leverage them inside of Substance Painter.   I know how to create the UV Tile Sets in 3DC and move the UVs for each portion of the mesh into them, I then tie that UV Set to a layer in the paint room and fill it with a unique color that binds a Material ID I believe (saw it on the Kalten Gun video)