Great video (no sound though) of giant dual-robot armed DLP Printer building some kind of monsterous resin stalagtite. It is called "Phantom Geometry" and is a masters thesis in architecture by husband and wife team, Kyle von Hasseln and Liz von Hasseln.
The project was developed in the Robot House at the Southern California Institute of Architecture (SCI_Arc) and awarded the inaugural Gehry Prize. The work is focused on the development of a system for generating material volume from streaming data. The creators state: "This system of fabrication relies upon native real-time feed-back and feed-forward mechanisms, and is therefore interruptible and corruptible at any time. The streaming data input may be transformed or modified at any time, and such" interventions impact emerging downstream geometry."
The layers are approx 3.5mm thick, cured in about 90-180 seconds slowing to as much as 500+ seconds as the build progresses (maybe the bulb was dying?). Clear resin was chosen partly to be able to cure thick layers as well as easthetic reasons. They were able to cure 1mm of resin about as quickly as 3.5mm. Layer thickness was chosen for speed & cost considerations. The main idea was to build a large, networked object within the intersecting workspheres of the robots allowing the object to bifurcate and merge with other neighboring stalactites. The second important idea is that the data was accessible in real-time. They were able to modify the 3d geometry as it was printed as well as the 2D image of the sliced 3D geometry right before it was sent to the projector. They were able to control layer thickness on the fly and add perforations. Because of this, they foresee very cool possibilities for scripting geometry.