Terragen is a neat program that creates 3D landscapes. You control the landscape shape by through the manipulation of a bumpmap.
What got me into Terragen? Well, Blender. Or might I say other users of Blender. See, you can create a landscape in Terragen, then export it into Blender. From there you imagination is the limit. A project that I
worked on for a long time (finally got burnet out!) was to download a DEM file (to find out what a DEM file is, go to USGS!) of my home town. I used 3DEM to render the image, then Terragen to landscape it. Add the grass and smooth the corners. Then export that into Blender and add buildings, cars, bridges and such. You can then export that in a landscapeing program that you can find with most flight simulators. I would then be left with a flyable version of my home town for say, MS Flight Simulator.
Despite everything else, I do have a life! And this project just started eating up too much of it. After two and a half months of weekends, I gave up. I might pick it up again someday, nut no time soon. Still, Terragen is a fun program to play with. Check it out at www.planetside.co.uk/terragen!