In 1983 Chuck Hull invented the first 3D printer. It could produce small plastic objects directly from a digital file on a computer. Instead of using ink the printer used plastic - adding layer upon layer to create an object. At first no-one was interested but now 3D printing technology is used widely, both by amateur hobbyists and industry. It's been taken up enthusiastically in the medical world to help separate conjoined twins and the next step is to help create human tissue for regenerative medicine.