POVray (an abbreviation of “Persistence Of Vision RAYtracer”) is a high-quality, free tool for creating stunning three-dimensional graphics. It uses a C-language type text file to describe objects, light sources, and cameras. There are some graphical frontends for POVray, as well as some tools for converting designs from CAD programs such as MLCAD and LDraw into POVray source files.

More information and free downloads are available at the POVray.org website.