texturing - Attempting to export as a .OBJ with .mtl, but the resultant .mtl file lacks an actual map - Blender Stack Exchange
Importing .OBJ file with .MTL file. how it works? - Rhino for Windows - McNeel Forum
How to import/add a MTL file – How can we help you?
31: What is a .MTL File?
problem with importing obj: it doesnt import mtl properly. i think it happens with every obj i import, this one is from daz and it should have skin and other materials but
python - PyOpenGL - How load obj file that has color defined in the mtl file - Stack Overflow