3D printing technology is becoming more accessible, more affordable, and more useful every day. From factory tooling to movie props, 3D has countless applications – and now, you can even print your own house! In this TED talk, University of Southern California professor Behrokh Khoshnevis talks about scaling up the processes already used in rapid prototyping technology, and working with a 3D printer that can print the structure of a 250 square meter house using concrete. A major limitation of the technology is that it only prints on a single level. Enrico Dini's British company D-shape hopes to expand on the possibilities of large-scale 3D printing, and has managed to print a two-level structure, but not a livable home yet. It raises the question of which direction this technology is headed – in the future, will we print taller, leading to constructive new methods of city-building, or will we print wider, increasing the already-rapid pace of suburban sprawl? And if it does lead to sprawl, who will print roads and sewer lines to serve the houses?