[2][3] He is one of the inventors of the SLA 3D printer, the first commercial rapid prototyping technology, and the widely used STL file format.
[9] But on July 16, 1984, Alain Le Méhauté, Olivier de Witte and Jean Claude André filed their patent for the stereolithography process.
[13] He defined stereolithography as a method and apparatus for making solid objects by successively "printing" thin layers of the ultraviolet curable material one on top of the other.
In Hull's patent, a concentrated beam of ultraviolet light is focused onto the surface of a vat filled with liquid photopolymer.
Hull built up a patent portfolio covering many fundamental aspects of today's additive manufacturing technologies such as data preparation via triangulated models (STL file format) and slicing, and exposure strategies such as alternating hatch directions.