I'm not at all a specialist of "how to simulate radiosity", but I saw in a magazine some month ago a technique consisting (exactly as you are saying) to add some colored lights (sometimes some negative lights) in some strategic points (the subject of the article was a very simple still life study, with two single objects, a ball above a piece of satin). I have not tried this precise technique in Vue, since placing several lights in a scene can gives some impressive results. But I'm more and more interested by your work, and have lot of things to learn from you, it seems. Thanks for Vue4.1 upgrading suggestion : if 4.1 is faster than 2.1, that's an other reason to upgrade. May I ask some questions ? You are speaking of "fill light" : it seems to be a Vue4 feature with volumetric atmosphere,isn't it ? I was very impressed by your "glass picture", and the glass reflection/ higlight were so perfect, that I guess what is the number of polygons you have used for each glass. I alway add some breaklines due to the relatively coarse mesh in my glass pictures ;=) Yves