Picogen is a rendering system for the creation and rendering of artificial terrain, based on ray tracing. It is free software.

While the primary purpose of picogen is to display realistic 3D terrain, both in terms of terrain formation and image plausibility, it also is a heightmap-creation tool, in which heightmaps are programmed in a syntax reminiscent of Lisp.

The shading system is partially programmable.

Currently there is a frontend to picogen, called picogen-wx (based on wxWidgets). It is encapsulated from picogen and thus communicates with it on command-line level. Picogen-wx provides several panels to design the different aspects of a landscape, e.g. the Sun/Sky- or the Terrain-Texture-Panel. Each panel has its own preview window, though each preview window can be reached from any other panel.

Landscapes can be loaded and saved through an own, simple XML-based file format, and images of arbitrary size (including antialiasing) can be saved.