Blender isn't a CAD program - but I know it pretty well, so I learned how to use it to design objects for my 3d printer - You just have to know a few basic secrets! In this demo, I show you how to set Blender up so that you can use millimeters and have your 3d objects sized correctly for a 3d printer. In subsequent tutorials I will show you some techniques of making 3d objects in Blender for your 3d printer.