World Machine - Command powerful tools like erosion and advanced colormaps to create terrain heightmaps, meshes, and textures for your game or 3D scene. Download for Free!

Vue - Create vast expanses of terrains, add trees, select the best point of view and render...

Picogen - The homepage of the free (as in freedom), GPL-licensed Terrain Synthesizer and Renderer named 'picogen'

Hexagon - Hexagon - Box Version

World Creator - World Creator is a real-time terrain and landscape generator and creation tool, which is industry proven by many game, movie and artwork companies.

EarthSculptor - EarthSculptor is a realtime terrain height-map editor and paint program featuring an easy to use...