Top two most used programs for designing/displaying objects are AutoCAD and Creo Parametric 2.0 (ProE)
AutoCAD (Auto Computer Aided Design) made by Autodesk
- Free for students with a valid .edu email address
- Beginner version from Autodesk is Autodesk Inventor
- Website: www.autodesk.com
- Plenty of free trials and apps on the app store
Creo Parametric 2.0
- Website: http://www.ptc.com/product/creo/3d-cad/parametric
- more user friendly
- Also offers a free trial
- Free Student edition available
Mastering either or both of these programs will be essential towards bringing napkin sketches into a real visualized object
Colton King's Engineering Blog 