Uses a light-sensitive liquid polymer. Requires post-curing since laser is not of high enough power to completely cure. Long-term curing can lead to warping. Parts are quite brittle and have a tacky surface. Support structures are typically required.
Uncured material can be toxic.
Ventilation is a must. A vat of photosensitive resin contains a vertically-moving platform. A laser beam traces out the shape of each layer and hardens the photosensitive resin . Because of the layered process, the model has a surface composed of stair steps. Sanding can remove the stair steps for a cosmetic finish.