Masterspec

4.0 Object Properties & Property Grouping

This section of the standard defines the properties that should be assigned to a BIM object. It also discusses the grouping of properties and the assignment of properties to object types or object instances.

4.3 IFC properties

  4.3 IFC properties
This sub-section of the standard defines the IFC properties to be assigned to a BIM object.
 4.3.1
IFC for interoperability
  To provide for greater interoperability of objects and models between different BIM applications, all objects shall include properties from the buildingSMART IFC4 (Addendum 2) schema that directly correspond to that object type.
   
 4.3.2  IFC object designation properties
 

The object shall include a property named ‘IfcExportAs’, with the value completed with the relevant IfcElementType’ from IFC4 (Add 2). For example, ‘IfcPile’, for a pile foundation.

The object shall include a property named ‘IfcExportType’’, with the value completed with the relevant PredefinedType’, selected from the enumerated list available for the nominated IfcElementType’. For example, ‘DRIVEN’, for a driven pile foundation.

Note: BIM authoring applications may automatically assign the ‘IfcExportAs’’ and ‘IfcExportType’’ properties, based on the in-built tools or templates used for modelling the object, see clause 5.2.1.

   
 4.3.3  IFC proxy object designation
 

If a relevant IfcElementType does not exist in IFC4 (Add2), for the object being modelled, then the ‘IfcExportAsproperty shall be completed with ‘IfcBuildingElementProxy’ and the ‘IfcExportType’ property shall be completed with ‘USERDEFINED’.

When the IfcBuildingElementProxy has been nominated, the object shall include an additional property of ‘ElementType’, with the value completed with a descriptive name to define the object type.

   
 4.3.4  IFC common properties
  If an IFC common property set (Pset_XXXCommon) exists for the object type, the properties from that property set shall be included.
If no IFC common property set exists for the object type, the properties from the IFC
Pset_BuildingElementProxyCommon property set shall be included.
   
 4.3.5  Additional IFC properties
  Additional properties and property sets from the IFC schema can be included, such as Quantity sets (Qto_) and environmental impact properties.
If a property in the IFC4 (Add2) schema addresses the same concept to that of a property proposed for inclusion, the IFC property shall be used.
   

 


 

 

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