buildingSMART Forums

IfcSill Development


Dear Community,

We would recommend to develop an own Class for Window- and Door-Sills e.g. with the Property Set “PSet_SillCommon” and a Quantitiy Set “Qto_SillBaseQuantities” for the next version. What do you think about that?



Interesting idea. There has been previous discussions about how to best handle greater detail in many types of objects and assemblies (Doors, Windows, Stairs, Railings, Curtain Walls, Trusses, Millwork/cabinetry, etc.).

I think “sill” might be too specific to warrant its own class. What if there were a more general “door/window parts” class that could have enumerations for the part function? Maybe an additional enumeration to IfcMember, or a new class like IfcOpeningAssemblyPart or IfcDoorWindowPart (there are IfcElementComponent and IfcBuildingElementPart, but they currently have very limited use? Then this could be embedded in the door/window or an opening assembly… which leads me to a further idea, and long-standing wish in some markets, about complex door and window assemblies…

What if there was IfcOpeningAssembly(there is already and IfcElementAssembly, but it is primarily used for structural elements). It would have a relationship to IfcOpeningElement, as does IfcDoor and IfcWindow currently, but the assembly could contain a combination of Doors and Windows as well as additional “parts” (IfcOpeningAssemblyPart) such as Sills, Lintels, Shutters, Security Devices, etc. Then you could have more specific Psets for each enumeration.