One of my student projects at University, was to design and make a plywood foldable stool for a workshop. I did this using the software Solidworks. After the design was complete I had to make DFX drawings so the stool could be produced in a CNC router, then sanded down the corners to a smooth finish and fixing the copper hindges in place. Once the design was fully constructed it was tested on its structual strength to withstand a persons weight, and it passed this test.