This presentation outlines the agenda, strategies, and findings of the “Modeling Hermogenes” seminar, a graduate course at the University of Pennsylvania that built a computer model of the Hellenistic temple of Artemis at Magnesia designed by Hermogenes (c. 200 B.C.E.). The aim of the seminar was not merely to generate a visualization of the now ruined building, but to use the modeling process to rigorously analyze the architectural remains, a sort of Bauforschung in 3D. Translating the meticulous 1904 pen-and-ink drawings into a digital model transformed the usual consideration of Hermogenes' plan of widened column spacing into an analysis of form, space, and spans. Building in three-dimensions the conjectural elements of the superstructure, coffering, and roofing, which are so often assumed and hidden in reconstructions, led to experiments that laid bare the construction challenges and possible solutions used at Magnesia. The experimental process revealed the engineering of the optical effects that earned this monument fame for its audacious spaciousness.