Number of doors and windows within one opening is restricted to max 1.
Based on IFC2x2, IFC2x3
Initiator ISG Meeting-Berlin
Effects Extended Coordination View
Date 2006 02 24
Each IfcOpeningElement shall only have zero or one filling. For door and window combinations (an opening with more then one window, door, or window and door), there are two possibilities:
* export it as one filling with a brep geometry containing all windows/ doors (multiple IfcFacetedBrep's are allowed as shape representation of IfcDoor or IfcWindow)
* export each window and door with a separate, but joining, opening element