CAD Software also known as Computer Aided Drafting software is the most powerful tool for creating advanced 2D and 3D designs that can be used CNC machining. CAD files are typically exportable in universal file types such as STL, IGES and DXF that can be interpreted by CAM Software which will ultimately allow for milling operations by a CNC machine.
CAD Software can cost hundreds to tens of thousands of dollars for professional engineering level software. Many free and low cost options have been developed recently for the Maker community.
Some of the most common CAD software includes: