thanks for the comments, maybe I will try to add other colored lights in the scene, in the same time I will try to change some textures. Concerning the dome, this is just an half of sphere object (very large, surrounding the scene, so you can not see it on the picture), with a mapped picture. The material of the dome is done with high level of diffuse and ambient, so it emits a large amount of "light" and the color of the objects in the scene are modified, as they were in a real environment, even in a very basic scene with only one or two objects. I don't know if my explanations are clear :) Yves