I have had students using Autodesk Inventor and Slic3r to design cars for awhile now. Students can design cars both with moving wheels and stationary. the cars are very easy to design, a 12 year old student has no problem going through the tutorial and producing the stationary wheel car in about an hour. As far as learning goes this project exposes students to a wide range of 3D modeling and printing techniques. Prior to designing the cars in Inventor teachers could go through the design process with the students and have them design their car around a given brief, or just let them have some fun with it. In order to differentiate the instruction of this project as much as possible I have made a written/picture tutorial and a video tutorial.