...It has value in support of existing software and raytrace scene files, which ranges from legacy files to existing CAD software that can export 3D scenes Rayshade can build a scene for.
Files Section has a patch allowing Rayshade to build in Linux more fully / less errors than the tiny redhat patch that can be found.
The Utah Raster Toolkit is a "depends" - it needs to be installed before Rayshade builds so images can become viewable format.
http://sourceforge.net/projects/rayshade/
http://sourceforge.net/projects/rayshade-math/
http://sourceforge.net/projects/utahrastertoolkit/
NOTE: Rayshade is unmaintained so no longer competitive to povray. ...
libPunts is a tiny 3D rendering engine focused on developing physics simulations. Gravetat is a gravity and electromagnetism simulator built over libPunts.
To provide users with a customized rendering pipeline, right down to how the bounding code bounds. TRRT is about providing the rendering pipeline you want and need, whether you render at a professional or hobbyist level. Will be RenderMan compliant.