Promotes development of tools for constructing any part of the real world in interactive, 3D digital form. CAD, GIS, visual simulation, surveying and remote sensing. (free, with code) [win32, unix]

Professional photorealistic terrain modeling, visualization, rendering and animation program. Create stunning, photorealistic images and animations with image object rendering. [Win9x/NT/2k/Mac/SGI]

A program for designing and creating virtual landscapes utilizing real map data or synthetic data from fractals. Fractals are also used to dynamically extend the data and level of detail. [Win 98/SE/Me/2k]

Aeliom allows real time generation, rendering, illumination, and exploration of 3d virtual landscapes.

Toolkit for building interactive real-time applications with 2D or 3D presentations, from simulators and command and control (C3I) to surveillance and traditional GIS systems. [Win9x/NT/2k]

Small program for playing with terrain data (height fields). Imports data from and to many popular file formats. Can use a number of image processing operations and height field painting tools. (Free, no code) [Win9x/NT]

Modeling and visualization software package that creates relief maps in both 2D and 3D using either proprietary global elevation database or public domain DEMs. Features include projections, texture draping, lighting, shading, and elevation color grad...

Produce and display charts of the world for users of FlightGear, an open source flight simulator. Includes map creator and atlas viewer. Can also be used stand alone. Under development, GPL. [Win32(cygwin), Linux]

Raytracing based landscape renderer with object (trees, rocks, lakes) creation, placement and animation capabilities. Interactive planimetric, and 3D modeling viewpoints. Imports USGS and STDS DEMs. [Windows and Mac]

Heightfield, bumpmap, and terrain modeler for Windows. Has an active user community with many 3rd party plugins. Downloadable demo with limited functionality.