How can I apply different physical materials on a single material?

[DavidMcEwen]

An option may be to use Physical Material Masks. This post covers how it works (as it doesn’t appear properly documented):

Physical Material Masks?

Create a mask texture with no more than eight colors. The colors must be the 8 colors listed in the material editor (and also PhysicalMaterialMask.cpp): red, green, blue, cyan, magenta, yellow, white, and black. I was able to do this by creating an RGB (no alpha) PNG in Blender. Create a Physical Material Mask asset in the Content Browser. Then, right click on the asset and select Import Mask Texture. Choose the PNG you created in step 1. Open a Material (normal material, not physical ma…

It will probably depend how your material is structured how useful it can be (as in can it relate to a static look up). The usage basically resolves to the raycast hit mapping to the UVs of the mask and returning the index of the physical material.