A system for generating three-dimensional objects by creating a cross-sectional pattern of the object to be formed at a selected surface of a fluid medium capable of altering its physical state in response to appropriate synergistic stimulation by impinging radiation, particle bombardment or chemical...http://www.google.com/patents/US5569431?utm_source=gb-gplus-sharePatent US5569431 - Method and apparatus for production of three-dimensional objects by stereolithography
