“Constructing an entire building is difficult and involves a lot of people, money, and time. With 3D printing, however, it’s possible to build a structure out of sustainable materials in just a few weeks and for an affordable price. Although many people dismiss this idea as just a far-off dream, a San Francisco company, Apis Cor, has proved it’s possible right now. The company 3D printed a house from the foundation to roof using a mobile printer that works in polar coordinates. (Windows, wiring and plumbing had to be installed by humans.) It is developing more advanced printers that can build inter-story floors and roofs, as well as horizontal walls and foundation reinforcement.”