We updated the support for 3D Models, no need anymore to restrict the number of Material to one for each Mesh in your 3D Model file. EEXAR now supports multiple Material under one Mesh, hence more complex and more detailed 3D Models. The Documentation has been updated accordingly, have a look here.
Note: Keep in mind 3D Design best practices such as: use a minimum number of 3D Meshes to optimize loading, especially for Augmented Reality