A new generation of rapid prototyping is set to further revolutionise the potential for architecture. Contour Crafting, developed by Dr Behrokh Khoshnevis, engineering professor at the University of Southern California, has developed a robot that its creator hopes will be able to build a 200m 2 house in 24 hours, working round the clock and requiring no food except concrete.
Rapid prototyping involves spraying layers of a polymer to form a physical 3D object based on a set of computational instructions. Thus, straight from your PC screen, it can create a scale model in essentially the same way your inkjet printer creates a document. The Contour Crafter's computer-guided, gantry-mounted nozzle emits concrete, or any other semi-liquid building material, in successive layers. Two moveable trowels on the nozzle then sculpt the material into practically any shape - geometrically regular or freeform - to form walls, curves and domes.
The robot builds a hollow outline and, on the next pass, both raises the outline by one layer and fills in the previous layer.
Other semi-liquid materials under consideration include adobe (a Native American construction of mud, grass and sticks), plaster, plastic and even a paste made of wood particles and epoxy. American science-fiction writer Bruce Sterling recently compared the Crafter to a termite, and mused that it would be ideal for construction in hostile environments such as the moon.
Khoshnevis foresees producing an 'instant house' by early next year.
He is working with Düsseldorf-based multinational chemical giant Degussa - which makes everything from 'kiss-proof' lipstick additives that prevent moisture loss to super-powerful tile adhesive that works on the same nanostructures that geckos use to climb walls - to find just the right building material.
But rapid prototyping will not remain the preserve of multinationals.
Dr Adrian Bowyer of the University of Bath's Centre for Biomimetics and his team are developing the RepRap (Replicating Rapid Prototyper), which can make copies of itself and other products for only a few pounds.
Conventional rapid prototypers cost around £25,000; Bowyer plans to put the 3D models that a rapid prototyper needs to copy itself on the web. In this way, conventional machines can create cheap copies of themselves until they become affordable enough for everyday use.
Marrying Bowyer's and Khoshnevis' ideas could allow architects to extrude a house from a CAD file inexpensively and overnight.