CV-2x3-120 (aka CV-06-120)

Material information for decomposed elements shall only be given at the element part level 

Based on          IFC2x3

Initiator            ISG Meeting-Munich

Effects              Extended Coordination View

Date                    2006 05 05


The IFC specification allows all subtypes of IfcBuildingElement (and other) to act as a container entity, i.e. to be a decomposed element having parts. This is expressed by an IfcRelAggregates relationship entity pointing to the container with RelatingObject and it referenced by the inverse attribute IsDecomposedBy. An example is a roof, containing two roof slabs:

    * IfcRoof <--RelatingObject-- IfcRelAggregates --RelatedObjects--> IfcSlab (PredefinedType=.ROOF.)

The following agreement is made:

    * If the building element is a container, then the material information (IfcRelAssociatesMaterial --> IfcMaterial|IfcMaterialLayerSet|IfcMaterialLayerSetUsage) shall only be assigned to the parts, not to the container

update [06-07-2011]

Initiator: Agreement for the IFC2x3 Coordination View V2.0

The material information may either be provided at the decomposed parts of the element container, or to the type of that part. Taking the example from above:

    * If the building element is a container, then the material information shall either be assigned to the parts, here IfcSlab, or to the type of the part, here IfcSlabType referenced by IfcSlab <-- IfcRelDefinesByType --> IfcSlabType.

See also Implementation Agreements CV-06-119 & CV-06-121

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