Script to convert standard maya shaders (Phong, Blinn, Lambert) to RenderMan PxrSurface. Original script is from https://www.highend3d.com/maya/script/maya-materials ...
This is a two part process that will allow you to convert Maya aiStandradShader to PrincipalBSDF. First, you will need Maya to export the geometry as an FBX file so that you can import it in Blender.