An imaging method and apparatus produces an integral three-dimensional object from a multiplicity of cross sectional portions of the object. The cross sectional portions correspond to photohardened portions of contiguous photoformed precursor sheets of a photohardenable liquid composition....http://www.google.com.au/patents/US5094935?utm_source=gb-gplus-sharePatent US5094935 - Method and apparatus for fabricating three dimensional objects from photoformed precursor sheets
