Virtual Scenery Generation: Terragen
by The EditorTerragen is a virtual scenery and terrain generator from Planetside and is available for Mac OS X and Windows. For personal use, Terragen is free.
From the Planetside website:
Terragen is a scenery generator, created with the goal of generating photorealistic landscape images and animations. It is available for Windows and the Mac OS. At this stage in its development, Terragen is free for personal, noncommercial use.
Although Terragen is a continually evolving work-in-progress, it is already capable of near-photorealistic results for professional landscape visualisation, special effects, art and recreation. Terragen has been used in a variety of commercial applications including film, television and music videos, games and multimedia, books, magazines and print advertisements. For just a small selection of projects Terragen has been used in, please visit the commercial use page.
Despite the fact that Terragen can be used for professional landscape visualisation projects, it is accessible and easy to get started with. You could be rendering your first landscape image in as little as 15 minutes after installation.

