There is currently a heated race to see who will be the first company to produce a 3D printed building. A variety of exciting solutions are being explored - everything from printing different densities of concrete, to layering polymers all the way to robot swarms are on the table as viable options.
One of the more outlandish ones is the ProtoHouse (I call it Spider House!)
You can see more images and a couple of videos at the source:
http://fineprintnyc.com/blog/making-...inted-building