I registered polyhedra.org back in 2000, after a late-night conversation with my friend Loden Muller, when we fantasized about making the ultimate web site about polyhedra. Two years later, I had a protoype almost completed, a set of PHP scripts that generated flash movies for individual polyhedra, each containing a large number of 2-dimensional vector graphics for each rotation angle. Except for the smallest models, the flash movies were unreasonably large. My child was born and I started a new job, so the project languished.
Viewer_3d uses the XMLHttpRequest element to download 3-d models represented in a simple XML format. This makes viewer_3d an AJAX application. Viewer_3d uses the painter's algorithm to manage hidden lines, and takes advantage of alpha compositing in the canvas element to produce a visual effect that I think is more pleasing than most other polyhedra sites on the web: a bit like sketches in a notebook.
Polyhedra.org is based on the Netlib Polyhedra Database compiled by Andrew Hume. George Hart has published corrections to some of the files. Gaps remain in the netlib data, and I am in the process of filling them in.