By the way, some members here are already producing scenes not a million miles away from what you describe. This straight Bryce render: is lit entirely without lights (less than an hour to render, even with refractive material). The illumination comes entirely from the sky, and light from that bounces off of the materials onto other materials - a sort of radiosity. This uses techniques I've already discussed in this forum. I haven't developed further because I came up against brick walls that I couldn't work around. I would be most pleased to be able to do this sort of thing under all circumstances with no grief.