Vat Polymerization is a method in 3D printing to print 3D objects by using photopolymerization, which is the process of exposing liquid polymers to ultraviolet (UV) light to turn liquid into solids. Digital light processing technology is used for the process.

First, a 3D design is created in a 3D software program. Then, the 3D printer uses digital light processing technology (which works as a projector) to project the image with UV light onto a vat of liquid polymers layer by layer. This process of draining and exposure to UV light is repeated until the object is complete, with the vat completely drained and leaving the solid 3D object.