Hi,
The BRL-CAD package is a powerful Constructive Solid Geometry (CSG) solid modeling system with over 20 years development and production use by the U.S. military. BRL-CAD includes an interactive geometry editor, parallel ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, image-processing and signal-processing tools. The entire package is distributed in source code form. http://brlcad.org/
Would like to know the feedback from any AUTOCAD users how good this package is, as I don't have any experience with CAD tools.
Cheers Praveen