This post may be a bit early, as I haven't found the full docs or gotten full instructions for the program, but while looking for more information on Aqsis, I ran across these links for Pixie.  

"Pixie is a photorealistic renderer that uses a RenderMan-like interface. Features include programmable shading, motion blur, depth of field, raytracing, scan-line rendering, occlusion culling, global illumination, caustics ...


Files here: http://sourceforge.net/project/showfiles.php?group_id=59462

http://sourceforge.net/projects/pixie/

Some docs here: http://www.george-graphics.co.uk/pi...iki.pl?HomePage

Multi-platform.