There are <i>thousands</i> of small parts in a car cab, made of a variety of materials (assorted alloys, glass, various plastics, composites, fabrics, rubber, electronic components...), and an unfeasibly large amount of wiring, some of which has to be thick enough to carry large currents.<p>Even if you strip everything down to bare essentials, you still need hundreds of parts in various materials. (Toyota, Peugeot and Citroen already do engine&#x2F;chassis sharing on a couple of budget car lines.)<p>Current technology can&#x27;t print a safe car windscreen, never mind a complete cab with safe crumple zones.<p>Car building is primarily a logistics, supply chain, and assembly problem, not a design problem. I don&#x27;t think a self-printed car solution will happen this side of 2030 - if ever - and it will probably need nano-assembly to be viable.