R.I.S.E. is an open source global illumination renderer for producing physically and biologically based photo realistic images. Product specifications, gallery, documentation, and downloads. [Windows, Linux, SunOS, Irix 6.5, Sun Solaris]
A game engine aiming towards three dimensional computer graphics which fits both human perception and the shape of the real world better than common polygon engines do. Linux.
A simple raytracer in development, it supports the basic features of a raytracer along with multi-threading. Many platforms are supported (Win32, Linux, and iPAQ).