FreeCAD is an Open source 3D CAD modeler under GPL & LGPL License. FreeCAD is multi-platform, and currently runs flawlessly on Windows and Linux/Unix and Mac OSX systems. It is full GUI application and also runsFreeCAD is to make heavy use of all the great open-source libraries like
OpenCascade – a powerful CAD kernel
Qt – the world-famous UI framework, and
Python – scripting language
FreeCAD itself can also be used as a library by other programs.