Construction has huge environmental footprint, accounting for 40% of material use and 33% of carbon-dioxide emissions worldwide.
At the University of Southern California, Professor Behrokh Khoshnevis developed Contour Crafting (CC) technology.
This technology has great potential for automating the construction of whole structures as well as sub-components.
CC is hybrid techniques which mix an extrusion process for forming the object surfaces and a filling process to build the object central part.
Using this process, a single house or a colony of houses, each with possibly a different design, may be automatically constructed in a single run, embedded in each house all the conduits for electrical, plumbing and air-conditioning.
In a study conducted by Khoshnevis and colleagues in 2009, CC resulted in a 75% reduction in total carbon dioxide emissions and lowered total embodied energy by 50% as compared to standard manual construction using a concrete masonry unit.
The potential applications of this technology are far-reaching including but not limited to applications in emergency, low-income, and commercial housing.
In the case of emergency, CC technology is the solution of providing fast, affordable, and dignified emergency housing.
By using materials that are available at the construction site, CC can build a single family house, equipped with reinforcements, electrical wiring, and plumbing in 24 hours or less.
Moreover, since CC is an automated process, labour cost is highly minimized and thus, injuries and fatalities are greatly reduced.
The speed of construction means survivors spend less time in tents and unsanitary living conditions.
In addition, the decrease in construction cost allows more fund to be allocated into other areas of development.
In this way, CC has the potential of providing disaster survivors not only with dignified shelter, but also with more resources to rebuild their lives and their community.
CC can automatically construct custom-designed structures by repeatedly layering down construction material.
It is an additive fabrication technology that uses computer control to exploit the superior surface-forming capability of towelling in order to create smooth and accurate planar and free form surfaces out of extruded materials (Zhang, and Khoshnevis 33-46).
CC construction technology has some advantages include:
• Flexibility for architectural design for custom designs to be fabricated directly from computer model of the building.
• Automatic imbedding possibility for plumbing, electrical and communication networks
• Cost effective and efficient (a 200 m2, two-story house can be built within two days)
• Efficient construction logistics and management
• Environmental friendly due to low emissions and waste
• Reduced energy usage contrast to manual construction
Source : Cooper-Hewitt, Why Design Now?; Contour Crafting.org; Information Sciences Institute; University of Southern California; The Register; Daily Business News; Contour Crafting Process Plan Optimization, Part II: Multi–Machine Cases, Journal of Industrial and Systems Engineering, Vol. 4, No. 2, pp 77-94, 2010,
 Zhang, Jing, and Behrokh Khoshnevis. “Contour Crafting Process Plan Optimization Part I: Single-Nozzle Case.” Journal of Industrial and Systems Engineering. 4.1 (2010): 33-46
 Khoshnevis B. “Contour Crafting – State of Development”; Solid Freeform Fabrication Proceedings 1999; 743-750.