1984
On 16 July 1984, Alain Le Mťhautť, Olivier de Witte, and Jean Claude Andrť filed their patent for the stereolithography process. The application of the French inventors was abandoned by the French General Electric Company (now Alcatel-Alsthom) and CILAS (The Laser Consortium). The claimed reason was “for lack of business perspective”.
Three weeks later in 1984, Chuck Hull of 3D Systems Corporation filed his own patent for a stereolithography fabrication system, in which layers are added by curing photopolymers with ultraviolet light lasers. Hull defined the process as a “system for generating three-dimensional objects by creating a cross-sectional pattern of the object to be formed,”. Hull’s contribution was the STL (Stereolithography) file format and the digital slicing and infill strategies common to many processes today.