BRL-CAD http://brlcad.org/ is a powerful Constructive Solid Geometry (CSG) solid modeling Computer-aided design (CAD) system. BRL-CAD http://brlcad.org/ includes an interactive geometry editor, ray tracing support for computer rendering and geometric analysis, computer network distributed framebuffer support, image-processing and signal-processing tools. The entire package is distributed in source code and binary form.