Hi Danny, also quick note re: .mtl file option - that option only actually has to do with OBJ format export.

The material definitions (like the actual color of the material) for OBJ format are not actually stored directly in the OBJ file itself, but rather in a companion MTL file that is written at the same time.

If you don't want that secondary file written when saving to OBJ format, you can disable that option.

- Michael