4.2.2 Classification Association

The concept Classification Association describes how objects and object types can be further described by associating references to external sources of information. The source of information can be:

  • a classification system;
  • a dictionary server;
  • any external catalogue that classifies the object further;
  • any service that combine the above features.

An individual item within the external source of information can be selected. It then applies the inherent meaning of the item to the IfcObject or IfcTypeObject.

The main attributes to be provided for a Classification Association are:

  • Identification: holds the key provided for a specific references to classification items (or tables)
  • Name: allows for a human interpretable designation of a classification notation

The following diagram shows the generic classes and relationships used when applying this concept. In addition, concepts may have particular importance to common or standardised industry practices and scenarios. For these specific usage scenarios, the tables below shows a recommended list of general usage patterns that users may adopt.

G IfcObjectDefinition IfcObjectDefinition 1. GlobalId [1:1] 2. OwnerHistory [0:1] 3. Name [0:1] 4. Description [0:1]      HasAssignments [0:?]      Nests [0:1]      IsNestedBy [0:?]      HasContext [0:1]      IsDecomposedBy [0:?]      Decomposes [0:1]      HasAssociations [0:?] IfcRelAssociatesClassification IfcRelAssociatesClassification 1. GlobalId [1:1] 2. OwnerHistory [0:1] 3. Name [0:1] 4. Description [0:1] 5. RelatedObjects [1:?] 6. RelatingClassification [1:1] IfcObjectDefinition:HasAssociations1->IfcRelAssociatesClassification:RelatedObjects0 IfcClassificationReference IfcClassificationReference 1. Location [0:1] Identification 2. Identification [0:1] Name 3. Name [0:1]      ExternalReferenceForResources [0:?] 4. ReferencedSource [0:1] 5. Description [0:1] 6. Sort [0:1]      ClassificationRefForObjects [0:?]      HasReferences [0:?] IfcRelAssociatesClassification:RelatingClassification1->IfcClassificationReference:IfcClassificationReference0 IfcIdentifier_0 IfcIdentifier IfcClassificationReference:Identification1->IfcIdentifier_0:IfcIdentifier0 IfcLabel_0 IfcLabel IfcClassificationReference:Name1->IfcLabel_0:IfcLabel0 IfcText_0 IfcText IfcClassificationReference:Description1->IfcText_0:IfcText0 IfcClassification IfcClassification ClassificationSource 1. Source [0:1] 2. Edition [0:1] 3. EditionDate [0:1] ClassificationName 4. Name [1:1] 5. Description [0:1] 6. Specification [0:1] ClassificationTokens 7. ReferenceTokens [1:?]      ClassificationForObjects [0:?]      HasReferences [0:?] IfcClassificationReference:ReferencedSource1->IfcClassification:IfcClassification0 IfcIdentifier_2 IfcIdentifier IfcClassificationReference:Sort1->IfcIdentifier_2:IfcIdentifier0 IfcURIReference_1 IfcURIReference IfcClassificationReference:Location1->IfcURIReference_1:IfcURIReference0 IfcLabel_1 IfcLabel IfcClassification:Source1->IfcLabel_1:IfcLabel0 IfcLabel_2 IfcLabel IfcClassification:Name1->IfcLabel_2:IfcLabel0 IfcIdentifier_1 IfcIdentifier IfcClassification:ReferenceTokens1->IfcIdentifier_1:IfcIdentifier0 IfcLabel_3 IfcLabel IfcClassification:Edition1->IfcLabel_3:IfcLabel0 IfcText_1 IfcText IfcClassification:Description1->IfcText_1:IfcText0 IfcURIReference_0 IfcURIReference IfcClassification:Location1->IfcURIReference_0:IfcURIReference0 IfcDate IfcDate IfcClassification:EditionDate1->IfcDate:IfcDate0
Figure 4.2.2.A

General Usage

Table 4.2.2.B