GstarCAD, a program of computer-aided design, is presented as an alternative to Autocad, the best known of the category and the 2012 version now surpassed all CAD competitors. It is a shareware CAD designing application that's comprehensive, professional and advanced.
Here are some screenshots to illustrate the features and user interface of this application:
3D Object Converter
LibreCAD
Autodesk 123D Design
Autodesk Fusion 360
Autodesk Maya