Markus Kayser, a snappily dressed graduate design student at the Royal College of Art, built a 3D printer that produces objects using only sand and sun. He shot this video outside Siwa, Egypt in May of 2011.
PV cells convert sunlight into electricity to power the computer, build platform, and other moving parts while a Fresnel lens converts sunlight into an extremely high temperature beam that melts the silica in the sand. The imprecise nature of the material and technique creates objects that have a beautifully handmade appearance, much different than the standard 3D printed look.
It’s an ingenious project and a gorgeous video. I look forward to seeing more of his work.