CAD stands for Computer Aided Design. The user will be supported in his work by autmatized processes. The most well-known CAD program is likely to be AutoDesk CAD. Other well-known programs include AutoDesk Inventor, Catia and SolidWorks from Dassault Systems, NX and Solid Edge from Siemens, just to name a few. There are also free CAD programs available under different licenses. The best known are HeeksCAD (BSD), FreeCAD (OpenSource) and QCAD (OpenSource).