SENSOR THAT SIMULATES RESIN OPTICAL PROPERTIES

A method and system for calibrating a three dimensional printing system includes a specialized sensor. The three dimensional printing system forms a three dimensional article of manufacture through a layer-by-layer process. Layers are formed by the operation of a light engine selectively curing photocure resin onto a face of the three dimensional article of manufacture. The sensor includes a photodetector overlaid by an optical element. The optical element simulates a "dense portion" of an optical path between the light engine and the face of the three dimensional article of manufacture being formed. The "dense portion" of the optical path includes a layer of photocure resin that is disposed between the light engine and the face of the three dimensional article of manufacture.