Possible to Bake Lightmass for two overlapping static objects without them affecting each other?

Hello all,

I would have guessed this would be a fairly common question, with all the VR stuff (and especially commercial VR configurators) going on, but couldn’t find anything concerning this thematic.

To clarify a confusing question with a simple example:

  • As a base environment, I have a room, set to static mesh, let’s call it “Room”.
  • Then I have two different meshes of kitchen sinks, let’s call them “Sink A” and “Sink B”, also set to static mesh.

The goal is to be able to always have the Room visible, and in-game be able to switch visibility between Sink A and Sink B (so the user can decide which of the two sinks he prefers) - the problem is that both sinks are supposed to occupy the same space in the room, so I can’t just bake GI with all 3 objects active, because Sink A + Sink B would occlude each others bake calculations.

I guess I could just bake GI for the Room only, and then set the mobility of both sinks to Movable so they get interpolated lighting from the Indirect Lighting cache, which was computed for the room only.
But for the sake of visual quality, I want both of the Sinks to have Lightmass baked lightmaps.

Is there a way to setup lightmass, so that only certain objects interact with each other in the lightmap calculations?
Say, Room + Sink A are baked together first as if only those two were visible, and then Sink B gets its bake pass by only computing its own + the Room’s mesh (but not affecting the already existing baked solution for the Room mesh!)?

I hope this was comprehensible, thanks in advance!

Push, anyone?