Aye, I'm interested in seeing the finished render in your light-test room... But I'll have to agree with PJF, this scene doesn't really call for True Ambience... Still, I think it was a lighting experiment, right? And you're trying to figure out how far light will bounce in Bryce and whatnot...? I think it's a great scene setup to test such a thing, but alas, Bryce doesn't bounce light. At one point, PJF (who I consider a "heavyweight", regardless!), myself, and a few others experimented heavily in True Ambience and the like... We were able to make light bounce with TA, but since there are no TA LIGHTS, per se, it is nearly useless as a tool... I DID figure out how to bounce a spotlight off a mirror, but alas, it wasn't something you could do in Bryce. It is easily faked, however. Hopefully they'll give us some cooler options in Bryce 6, give us some new toys and techniques to play with!