3D printing techniques will be used to construct buildings, here and in outer space

'Contour Crafting' can be used to build the shell of a 2,000 square foot house in less than 20 hours

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The structures can look like the Adobe structures made of mud, clay and straw (or other domestic materials) in Africa, West Asia, and more arid parts of the Americas. Adobe structures have been a construction method for thousands of years; and can last hundreds of years.

"The reason they last is not the material. The strength comes from the geometry," Khoshnevis said. "The worst structures you can use are planar [flat] walls."

Khoshnevis demonstrated the strength of a contoured structure by holding a sheet of paper up and blowing on it, which bent if over. He then rolled the paper in a semi-circle and blew on it again; it remained upright.

Using Contour Crafting on the Moon and Mars

Khoshnevis, also a professor of aerospace and mechanical engineering at USC, is also working with the National Aeronautics and Space Administration (NASA) on a plan for creating structures on the Moon and Mars.

"The proposal we have is rather than take segments of buildings and transport them there, just take the machinery there ... and use the local material and make them there," Khoshnevis said.

The USC team is in phase two of an advanced concept for the off-world structures.

"The objective of NASA is to build settlements, outposts," he said. "Nothing's been said about human operated missions. Those can come later."

One problem with constructing landing pads, roads, or blast walls to protect living quarters on other planets is that water cannot be used. Because of the thin atmosphere on Mars, and lack thereof on the moon, water would evaporate from cement or concrete, leaving it to return to its origin of dust and rocks.

The USC researchers solved that problem by melting sulfur for use as a binder, binding the sand like cement.

"We have already shown the ability to build using Martian materials," he said.

The USC team also came up with a plan to combat the high temperatures on the sunny areas of the Moon -- creating interlocking ceramic tiles that can resist temperatures of up to 2,000 degrees Celsius. The tiles can be locked together to create structures. The machines could not only extrude the ceramic material, but a separate component could them assemble them into structure.

Another method of building structures is to use lithium disilicate, a glass-ceramic material that can be heated and poured out like molten lava to form structures on off-planet worlds.

While robotics could handle construction off world, here on Earth Contour Crafting would require far fewer laborers to build houses and other structures. Labor makes up 45% to 55% of construction costs, Khoshnevis said.

"It could be much cheaper than prefab structures and much, much cheaper than conventional construction," he said. "Nothing beats contour construction on cost."

The labor issue has already become a point of controversy -- some observers have have complained that machines would replace construction workers, leaving them without jobs, Khoshenevis said.

"My response to that is it's not going to happen overnight," he said. "Second, this is not a new question. When the steam engine was invented they said what's going to happen to carriage drivers?"

Khoshenevis pointed out that at the end of the 19th century in the U.S. 62.5% of Americans were farmers. Today, less than 1% work to grow our produce. "The world did not come to a standstill from such a major change," he said.

Behrokh Khoshnevis, a professor of industrial & systems engineering, at the University of Southern California, narrates a computer-animated demonstration of how 3D printing could be used to build entire neighborhoods.

Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian, or subscribe to Lucas's RSS feed . His email address is lmearian@computerworld.com.

Copyright © 2013 IDG Communications, Inc.

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