3ds max Lighting Assigning a diffuse material click on the button labeled assign material to selection. And now that assignment's been made, we can close the material editor, also close the scene explorer, de-select all of the objects, give focus to the perspective view, and do another active shade render. And now we have a diffuse neutral gray material assigned to all the objects, which is appropriate for setting up our lighting tests. That's how to assign a diffuse material to the objects in a scene in preparation for lighting.
