An apparatus and the method of its operation for 
rapid prototyping of a three-dimensional object which includes a 
radiant energy source of a 
wide beam of 
radiant energy of suitable intensity and 
wavelength for curing a layer of photo-curable resin contained in an open vat, a 
spatial light modulator (SLM) having an array of pixel elements which are individually digitally controllable by a computer, for modulating the 
radiant energy beam projected from the radiant 
energy source on a pixel by pixel basis, to form a series of time sequential images of the cross-sectional laminae of the object, an optical 
system for focusing each image formed by the SLM, one at a time, onto successive 
layers of photo-curable resin for predetermined 
exposure times to thereby form stacked laminae of cured resin, each lamina of cured resin being in the shape of a different one of the cross-sectional laminae, and a 
piston support for lowering each lamina of cured resin after it is formed by the SLM and for depositing a layer of resin corresponding to the thickness of one cross sectional lamina of the three-dimensional object before the step of projecting a new image by the SLM. The SLM, the 
piston support for lowering, and the optical 
system operate repeatedly and sequentially until a complete copy of the object is thereby produced.