I just struggling with the following task. I have a model of a building with a lot of window plates which should be reflecting some fictive buildings around. The texture for the reflections is stored as a sphere map. The resulting image should have a solid white background. The environment map should not influence the scene lighting at all. Is there any option to use the world node for the environment map while keeping the white background? I would like to avoid compositing as I will have to use it heavily for other stuff.
So far, I have achieved to use a large sphere to which I map the environment texture. The reflections are rendered perfectly, however the geometry of the sphere blocks the sun lamp. Thus, the scene gets rendered with ambient occlusion only. Is there a way to let the rays of the internal blender renderer to pass the sphere from the outside and to hit it from inside? Basically I just need to flip the orientation of the triangles for the sphere. A solution with different layers is also no option for me as I will need them for blending-in parts of the building in an animation.
Thanks for any suggestions