Picogen is a program to create, design, and render artificial 3D terrain scenes. It is currently not very nice to non-programming-end-users, as the heightmap definition is a program with a LISP-like syntax. It aims to be similar to the Terragen program and provide a free and unrestricted alternative to it.
PyCAM generates toolpaths (GCode) for CNC machines out of 3D STL model files or 2D gravure contour files (SVG or DXF). The output of PyCAM can be imported into EMC2 or other machine controllers to direct the milling machine. PyCAM features different path generation strategies, cutter shapes, and post-processing options.