That's quite intriguing there Joerg, and it sounds rather ambitious. I have my default new scene set up with 20 non-shadow lights, but that's a far cry from what you have done here. I don't understand what you mean when you say, "The lights must automatically take the colour of their background of the skydome." Do you mean, for example, that if a part of the skydome is near trees, the lights in that region should be greens? It would be very cool for E-on or someone to bring us even just a little closer to radiosity, but your method seems like it would work, and it's especially good that all those lights would not add significantly to the render time. Is this the same idea behind "real" radiosity?. I'm going to have to try this out! Thanks much, this could be VERY useful!