Height Map Editor - Free program that edits, generates, and manipulates terrain height maps. These can be used in terrain renders, which are used in games, applications, and demos. Web base manual available. [Windows and Linux] Virtual Terrain Project - 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] Blueberry3D - 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] Atlas - The FlightGear mapping utility - 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] Natural Scene Designer - 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] OBVIO - A free win32 3D viewer which demonstrates Dynamic Level of Detail (DLOD), based on OpenGL and GLUT, only reads USGS DEMs. Appears to be in active development. KLevel Heightfield Tool - A heightfield modelling tool designed to mimic Leveller for Windows. It features an OpenGL preview and many brush-like tools. (free, with code) [Linux] World Construction Set - Professional photorealistic terrain modeling, visualization, rendering and animation program. Create stunning, photorealistic images and animations with image object rendering. [Win9x/NT/2k/Mac/SGI]