1. A method for performing calculations related to a region of open space in a computer-aided design model (CAD model), comprising: identifying a region within a CAD model at least partially bounded by a set of drawing elements; generating a space object representing the region, wherein the geometry of the space object is determined using the set of drawing elements bounding the region; associating the space object with the set of drawing elements bounding the region; and calculating at least one area associated with the region, based on the geometry of the space object.