In the physics-free space of computer simulation, a house materializes in five minutes flat. Another name for rapid prototyping is “object printing,” and, in effect, Khoshnevis is suggesting that he could print a house. The gantry system with its concrete-spouting nozzle is in essence just a heavy-duty version of an ink-jet printer — here each layer would be several inches thick. Khoshnevis’ team have also worked out a fully automated system for putting in the pipes and the electrical conduits; they could even automate the painting, literally printing colors and patterns directly onto the walls. About the only thing left to do manually is to grade the lot, prepare the foundations, and put in the windows and doors.
But a question remains: Is home building something that should be automated? Khoshnevis believes the answer is unequivocally yes. He notes that skilled construction workers are increasingly in short supply and that each year more than half a million people are injured on construction sites. Moreover, with traditional building methods, material wastage is enormous — 3 to 7 tons is typical for a suburban house. Khoshnevis claims that his technology would cut waste, reduce accidents and save money; he estimates a cost saving of at least 50 percent. It’s hard to imagine construction unions signing on to such a project, and Khoshnevis certainly expects union opposition. But as he points out, we are moving toward a society in which almost everything is fabricated by machines. Why should houses be different? “We have all this sophisticated technology and know-how,” he says. “Why shouldn’t we apply it to building?”