Select a rectangular ceiling aperture in your ARCHICAD project and choose the ArchiGlazing command in the Design menu. Specify the remaining parameters for the glass structure in the Shed Glass Structure Settings dialog box and confirm your choices with OK. The shed glass structure will automatically be positioned over the ceiling aperture. In this way, the ceiling aperture corresponds to the overall (inner) diameter of the shed glass structure.
Note: Make sure to select ONLY the hole, not the whole slab to use this function.