Charles (Chuck) Hull invented Stereolithography, Stereolithography (STL) files, and is the co-founder of 3D Systems. He currently serves as the Executive Vice President and Chief Technology Officer at 3D Systems. Hull patented Stereolithography and co-founded 3D Systems in 1986.

Stereolithography uses a photopolymer process in which liquid resin is exposed to an ultraviolet (UV) laser, which traces a layer of the 3D model image onto the resin. The exposure to light causes a layer of the resin to solidify. The build platform rises and the resin is again exposed to the laser. This process repeats until the part is complete.