Interesting thread, Aldaron. I think you'll find that the render time estimate given by Bryce for your TA scene above is a big underestimate. I've noticed with the advanced render options in Bryce5, particularly True Ambience, that the final pass takes an absolute age compared to prediction in complex scenes. I'm currently rendering a scene that was predicted to be about 12 hours, but will actually be more like 36 hours. In your scene you have about 450 shadow casting lights. This is really asking for trouble with True Ambience, and I suspect the render would actually take several weeks to complete. But the main benefit of using True Ambience is to reduce the number of lights needed to fake light bouncing (light arrays and such like). Using the two together misses the point of both, and combines the worst of both worlds. I believe that True Ambience is designed to achieve a similar job to what radiosity engines are designed to achieve, although the specifics of the process are different (and not as effective). I know my views are not popular amongst the forum 'heavyweights', but I maintain my position with good reason. I'll post more on this in a couple of days. As regards materials behaving in the manner that you mention in your last post, Bryce already has them. Under True Ambience (suitably set up) darker materials 'reflect' less light than lighter ones. Black will 'reflect' nothing; white will 'reflect' the most of all.