BRL-CAD

BRL-CAD is an open source software which you can use it for free. It offers an innovative methods for creating solid modeling such as 3D geometry.This product is has extensive design which is being actively maintained by community developers. It does support on many operating system which includes Windows, Linux, Solaris, Mac OS and many others.

This software has been the choice of U.S Military since it has a lot of powerful libraries to select from.

Each of those libraries have different functionalities in terms of creating, editing and image handling. It totally offers geometric conversion, interrogation and command-line-oriented image manipulation.

The software can be download for free in their site. So how about that, a free CAD that you can use for your design projects.

Image used are owned by BRL-CAD