Materials and Shaders
The Materials provided by the plugin are made using shadergraph, this means they only work correctly if the universal render pipeline is enabled and in use. It is possible to supply custom materials in which case the color map is uploaded to “ColorMap”, the metallic roughness to “MetallicRoughnessMap”, and the alpha map to “AlphaMap”. These values are also visible when selecting the shader (not the material) in the Inspector window.
Note that Unity’s standard PBR model uses a metallic smoothness map where metalness is stored in the R channel, and smoothness in the A channel, however the textures used by us, follow the 3JS standard of storing metallness in the B channel and roughness (1 - smoothness) in the green channel. If you make a custom PBR shader you need to take this into account.