In the above reply, it was mentioned to stay with surfaces as much as possible. What happens when you have an opening in a wall, you can't use boolean operations on surfaces ? Do you suggest that one should model the opening in the wall.
ie: Two surfaces for the left and right had sides of the opening, two surfaces for the top and bottom of the surfaces. A total of four surfaces to create the opening rather than using a region an subtract the opening from the region ?
I would use the model in VIZ and Lightscape, if this matters.