the guys at eyebeam atelier have developed an interesting plugin that will let you rip open GL information from software like google earth and doom and use it to generate 3d models. it’s called ogle. this would really make things interesting if there was a 3d library of topomaps, but I haven’t found one yet that runs on open GL. if anyone knows of one, send it my way.
in the meantime there are two sources of geographic information that are worth mentioning. one is topodepot , which is a pay service but allows one free download, and the other is the usgs, which is free but uses the .DEM format (after a conversion or two). the best way to make .DEMs useful is to import them into formZ, but it’s hard to coordinate what the topography corresponds to. again, if someone knows a better method of dealing with .DEMs, send it my way.