BRL-CAD is a computer aided design system. It was originally created in 1979 at the U.S. Army Ballistic Research Laboratory to perform simulation and analysis of "combat vehicle systems and environments." It retains an emphasis on engineering analysis but has grown to become a general purpose system for both Computer Aided Design (CAD) and 3D modeling workflows. BRL-CAD follows the UNIX design...

FreeCAD is a general purpose 3D modeling and computer aided design (CAD) tool. Its developers state that it is "made primarily to design objects for the real world." Objects designed in FreeCAD can be exported in formats suitable for 3D printing with a variety of devices or even production using CNC machining tools. In addition, FreeCAD is suitable for constructing 3D models of buildings,...