Some or most of you understand, intellectually, how an SLA 3D printer works: Light is fired in a particular pattern into liquid resin, curing a thin layer of it. Subsequent layers are built atop (or beneath) the one before. But in this video Bill Hammack, a/k/a The Engineer Guy, breaks down precisely how an SLA 3D printer does what it does, using Autodesk’s now open-source Ember DLP model to demonstrate: