I've been playing with Aqsis 1.8, using point based color bleeding. Just wanted to show what a big difference indirect lighting can do to a very simply scene composed of a few spheres and cubes and one ambient light.
Here is the scene rendered in one pass using a standard ambient light and a basic ambient surface shader.
There are 4 cubes and 4 spheres in that scene but it looks like there are only 3 spheres.
And now here is the same scene rendered in two passes using indirect lighting.
The first pass bakes into a point cloud and ambient color is used for the _radiance. The second pass uses the same basic ambient surface shader but with the addition of the indirectdiffuse() shade op to add to the ambient. Note: I did not use the occlusion() shade op.