I don’t normally recommend online courses, but seeing as what they’re teaching isn’t really being taught anywhere else at the moment at this general basic level, it’s worth sharing.
3Dprint.com is running a series of Beginner Design for 3D Printing and Advanced Design for 3D Printing online courses. These are courses designed for providing individuals with essential knowledge of preparing CAD models for 3D printing, and basic tolerances and design principles for building objects for 3D printing in plastic and other materials. Considering this information is always useful for CAD designers and only taught in a few places (besides my own courses), I reckon it’s worthwhile. We’ve missed the early bird registration, but there is still time to enrol for the summer courses starting on 20 June.