[IFC4.3] Which Ifc class to use for structure gauge?

Martin156131

So i used this tool here https://blenderbim.org/search-ifc-class.html
And it did not show me a suitable ifc class.

A structure gauge is simply put a virtual volume reserved for vehicle -> it's relevant for road, rail, bridge and even buildings <- if you built for example a car park

https://en.wikipedia.org/wiki/Structure_gauge

Does someone know?

Moult

IfcVirtualElement with predefined type of CLEARANCE.

http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcVirtualElement.htm
http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcVirtualElementTypeEnum.htm

In IFC4 you'd use IfcBuildingElementProxy with PROVISIONFORSPACE (which was migrated and renamed to CLEARANCE for clarity to prevent confusion).

Martin156131

Thanks for the info!

What about IfcSpatialZone with predefined type of SECURITY?

http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcSpatialZone.htm
http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcSpatialZoneTypeEnum.htm

What is the difference?

Moult

Security zones are like this https://www.protectivesecurity.govt.nz/physical-security/lifecycle/design/apply-good-practices/security/

Martin156131

So when i create an ifc with just an structure gauge, how should the ifc be structured?

The use case for this example is the Domain Road (highway) -> each discipline create their own little ifc model and in the end there should be a federation <- to dedect a collision for example between a bridge and the structure gauge.

Variant 1:
IfcProject -> IfcSite -> IfcRoad -> IfcRoadPart -> IfcVirtualElement (Predefined Type: CLEARANCE)
Variant 2:
IfcProject -> IfcSite -> IfcRoad -> IfcSpatialZone ?? (Predefined Type: SECURITY) ?? -> IfcVirtualElement (Predefined Type: CLEARANCE)

Or any other variant, i am open for suggestions :)

Another question: Why is there no Pset_Clearance? Was there no need?

Martin156131

When i read the http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcShapeRepresentation.htm website -> there is in the Table 8.18.3.17.O (indicates the defined list of values for RepresentationIdentifier) Clearance as a value, see in the image below:

So now we have defined two times Clearance? One time in IfcShapeRepresentation and one time in IfcVirtualElement ?