The Blender lighting in the foreground is all panels and spots to fake the sunshine, and simple emission materials for the inside light bulbs. I just felt that, for an interior scene, I had better control over materials and textures in Blender, a fact that may be due as much to my being a beginner in TG as anything. All the rooms in the Blender model are already setup with furnishings, so I'll do all those with composited TG views, and then stay exclusively in Terragen when I do exterior shots. I have a lot to learn just in making trees and such look more realistic, as DocCharly and WASasquatch mentioned.