Nem's Mega 3D Terrain Generator is a free, simple yet powerful 3D terrain generator for Windows, developed by Ryan Gregg in 2005, using C# and C++.NET. It comes with intuitive 3D drawing tools, texture customization, multiple export options, and other settings, and allows you to create stunning, realistic 3D terrains quickly and easily.

Grome (short for Ground Moeling Environment) is a 3D simulation software for game environment that was especially designed for game developers, developed by Quad Software from Romania in 2007. However, its applications are not limited to entertainment industry. More than a terrain editor/level editor, it is also a complete scene constructor. In fact, it was also successfully used in some other cases, for example: virtual reality projects, real-time 3D simulation, the creation of scenes for offline rendering, and more.

World Machine is a powerful and flexible 3D world terrain generator specially designed for game engines or 3D rendering software. It provides procedural terrain creation, simulations of nature, and interactive editing for you to produce realistic terrains with high-resolution heightfields, textures, and meshes.