Stereolithography

Stereolithography emerged from a tabletop experiment with protective coatings. In the early 1980s, Chuck Hull was working at UVP, Inc. in California, developing methods to cure resins with ultraviolet light to protect tabletops from wear. The insight struck him: if light could solidify resin on a surface, it could solidify resin layer by layer to build three-dimensional objects. The first 3D-printed part was created in 1983.

Hull filed his patent on August 8, 1984—a date now considered the official birthdate of 3D printing. The application, titled "Apparatus for Production of Three-Dimensional Objects by Stereolithography," coined the very term. The technology was conceptually simple but practically transformative: a concentrated beam of ultraviolet light, moving under computer control, traces each layer of an object onto the surface of a vat filled with liquid photopolymer. Wherever the beam strikes, the resin solidifies. The platform lowers, fresh resin flows over the hardened layer, and the process repeats.

But Hull was not alone in discovering this adjacent possible. Japanese researcher Hideo Kodama had published the layered UV-curing concept in 1981. Three French inventors—Alain Le Méhauté, Olivier de Witte, and Jean Claude André—filed their own patent on July 16, 1984, three weeks before Hull. Their patent was granted two months earlier than Hull's, in January 1986. Yet the French company behind the research abandoned the idea, seeing no commercial potential. Hull saw it clearly.

He founded 3D Systems in 1986 to commercialize the technology. The first commercial system, the SLA-1, shipped in 1987. Hull made two contributions beyond the hardware that ensured his dominance: the STL file format, which became the standard for translating CAD data to 3D printers, and the digital slicing strategies that most 3D printing processes still use. Today, Hull holds over 100 patents. He was inducted into the National Inventors Hall of Fame in 2014 and elected to the National Academy of Engineering in 2025.

The convergent emergence across California, Japan, and France within a three-year window demonstrates that the adjacent possible was primed. UV-curable resins existed. Computer-controlled motion systems existed. CAD software existed. The only question was who would assemble them—and who would recognize the commercial potential that others missed.