it would be cool if the mentioned path traced reference mode was an option in the game.
so they actually generate the scene brick by brick, not using volumes?
One of the things he demos in the shadow section of the talk is how some of the bricks stick out (“proud” in woodworking, dunno about masonry) and I suspect that would be more difficult to do with volumes. However from some of his diagrams it looks like some of the shadow and reflection work ends up doing some convex hulls.