The Science Corner

Also known as rapid-prototyping fabrication processes, these technologies, in essence, convert a design, expressed in a suitable language, into an accurate, compact model of a structure by building it up layer by thin layer.
In one such 3D-printing process, a high-powered, computer-controlled laser fuses nylon dust in places where the designer wants solidity. The dust left in the voids can be vacuumed away later, leaving the model, in all its intricacy, intact.

For more information: http://www.sciencenews.org/articles/20051224/mathtrek.asp