Terragen
Terragen is a scenery generator program for Microsoft Windows and Mac OS X developed and published by Planetside Software. It can be used to create renderings and animations of landscapes.
History
Released in stages (tech preview and beta) to a participating community, Terragen 2 was released to pre-purchasers on 2 April 2009. Terragen 2 is offered in feature limited freeware and full featured commercial licenses.
Planetside Software released the first public version of Terragen 2 after more than 3 years of development of both the core technologies and the program itself. Since then there have been several released updates to both licenses of the software along the development cycle with a series of technology previews and a beta release. The "final" build was released on April 23, 2009 and more updates, including feature modules are expected to be released later.
Planetside released Terragen 3 in August 2013. Version 3.1 was released in February 2014.
Terragen Classic
Terragen Classic is popular among amateur artists, which can be attributed to it being freeware, its intuitive interface, and its capability to create photorealistic landscapes when used skillfully. It can also use DEM (digital elevation model) files, and other graphic surface maps for rendering.