Hello,
i did face the same issue today on the watch hands of my latest model.
They are animated (thanks again to @kdv who helped me get it working) and minute and hour hands include 2 materials
To get this fixed, I did detach the parts using MatID2 and then i created a dummy for each hand, linking the 2 parts of the minute, and the 2 parts of the hour hands
Using a dummy will help you to get the materials assigned as required
Obviously, this isn’t the perfect solution, especially if you have hundreds of meshes, but it is at least a more or less good workaround
A little helper, for large scenes, is this 3ds script
Detach by ID
Using it quite often to split meshes into more manageable parts
Hope this helps
Senior CGI Artist @ 3DCGI.Studio #zerophotography
➤ Unreal Engine - 3ds max V-Ray
➤ Hyper-realistic 3D. Cars, Motorcycles, Products, Archviz Visualizations, 3D & VFX Animations