Chuck Hull invented the first stereolithography (SLA) printer in the early 1980s and this led to the co-founding of 3D Systems, one of the leading companies in the 3D printing industry today. Since, there have been several variants of SLA, all fundamentally based on the vat photopolymerisation process. Namely using light to cure a photosensitive material. There are other polymer 3D printing methods, such as fused deposition modelling (FDM), material jetting (MJ) and selective laser sintering (SLS).