Material Collections

It would be awesome to have Material collections as a way to "override" objects materials. Using that in combination with View Layers or Scenes will allow to create Render Passes easily.

ie: 3 Objects in a scene, Object_A, Object_B, Object_C

• 1st View Layer (Base_Layer): Every object has his own different material.
• 2nd View Layer (RGB_Layer): Object_A is inside one Collection with a material applied, ie Red color. Object_B is inside another Material Collection with a Green material applied. And Object_C is in a third Material Collection with a Blue material applied.
• 3rd View Layer (Mask_Layer): Object_A and Object_B are in a Collection with a full reflective material applied. Object_C is in a Collection with a white material applied with visibility set to not render in Camera. That way you get a clean mask of the Reflection of Object_C to later use in composition.

Obviously, in the same View Layer an object must be in only one Material Collection, otherwise the renderer will not be abble to know wich material to render if the object is in various Material Collections. It would be needed some kind of icons to mark if a Collection has a material applied or any visibility properties changed.

There would be infinite uses for this.

I try to add some "self-explanatory" images as reference to better understand the concept.

Cheers, Ignasi aka Topeich