Origin The model is based on a tomography scan on an antique window glass fragment from Ephesos (today Efes, Turkey). The sample was contributed by the Austrian Archaeological Institute, Vienna, and has the inventory ID EVH12/1017/1322. The original scan data is published as Grobe and Schuetz (2021). Computed tomography scan of Roman window glass from Ephesos. doi:10.5281/zenodo.5651890 and is described in: Grobe, Noback, and Schuetz (2021). A model chain to simulate daylight in historic built environments. Presented at: Widening Horizons - 27 Annual Meeting of the European Association of Archaeologists, Kiel, Germany. doi:10.5281/zenodo.5495764 Processing The scan was processed to prepare its conversion into a simulation model, i.e. small isolated mesh components were deleted, disconnected and duplicate vertices and faces were removed, the outer surfaces were re-constructed by meshlab's implementation of the _Screened Poisson_ algorithm, and the resulting mesh was intersected with an exctruded rectangle.