Our website provides a free download of Terrain3D 4.2. The most popular version among Terrain3D users is 4.2. Terrain3D relates to Photo & Graphics Tools. This free program is a product of Saiz, Inc.
From the developer:
Terrain3D software is a graphic tool for the game "Sailors of the Sky” . It is used to create additional soaring sceneries / locations from simple road maps. It should be noted that all of the gliders and scenery supplied with the program have been created with these programs at their current state of development.
You may want to check out more software, such as Wire Pilot Plugin, which might be related to Terrain3D.