I have a modelling and exchange question.
The IfcSpace can have a real or a theoretical boundary for the definition of a particular space and its quantities. This applies well for horizontal spaces with slight deviations in vertical aspect ex. suspended ceiling. The geometry becomes a bit more complicated at the vertical aspect, especially in staircases. What is in this case the boundary of a space in a staircase considering the net areas of surfaces, volumes and other quantities? How does the geometry of the stair itself impact the geometry of the space?
So, is the IfcSpace a boundary which corresponds to other horizontal spaces in that specific floor or should it have a very complex geometry (Space body clipping by stair) to represent the actual space from story to story?! The first option is easier in the modeling aspect but has wrong volumes and the second on might have correct volumes but is geometricaly almost impossible to represent (boundary)
The below picture represents the IfcSpace corresponding to the spaces in a storey