Summary
This final blueprint explored techniques for modeling 3D objects to fit when 3D printed. Measuring tools such as calipers are valuable aids to any 3D modeler, and using a scanner and ink pad is a clever technique to capture complex objects' shape, provided they have a flat side that can be used like a stamp. The grid paper method is a useful method that works in a surprising number of cases.
Perhaps, one day 3D scanners will be as ubiquitous as their 2D counterparts, but until that day finding ways to transfer real space into the digital space is a problem that will challenge 3D designers. Being creative about making accurate measurement will continue to be a rewarding challenge.
With this last technique, there should be nothing we need for designing objects for 3D printing. Congratulate yourself, you are now a 3D designer. Now the challenges are yours. Find objects that you want to make and model them, if you haven't already started. Find a need and fill it with a plastic object....