A three dimensional printing system includes a vertical support, a support plate, a resin vessel, a fluid spill containment vessel, and a light engine. The support plate is affixed to the vertical support at a proximal end. The support plate has an inner surface defining a first central opening. The resin vessel is supported above the support plate and has an inner edges surrounding a second central opening. The resin vessel includes a transparent sheet that closes the second central opening. The fluid spill containment vessel is supported below the support plate and includes a transparent window. The light engine is supported below the fluid spill containment vessel. The first central opening, the second central opening, and the window laterally overlap to provide an optical path whereby the light engine can project light upwardly to a build plane in the resin vessel.