IfcPropertyDependencyRelationship

Natural language names
Merkmal - Abhängigkeitsrelation
Property Dependency Relationship
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcPropertyDependencyRelationship
      NameXXMODIFIEDName changed from DependingProperty to Name.
Type changed from IfcProperty to IfcLabel.
Instantiation changed to OPTIONAL.
      DescriptionXXMODIFIEDName changed from DependantProperty to Description.
Type changed from IfcProperty to IfcText.
Instantiation changed to OPTIONAL.
      DependingPropertyXXMODIFIEDName changed from Name to DependingProperty.
Type changed from IfcLabel to IfcProperty.
Instantiation changed from OPTIONAL.
      DependantPropertyXXMODIFIEDName changed from Description to DependantProperty.
Type changed from IfcText to IfcProperty.
Instantiation changed from OPTIONAL.
IFC2x3 to IFC4 4.0.0.0
    IfcPropertyDependencyRelationship
      NameXXMODIFIEDName changed from DependingProperty to Name.
Type changed from IfcProperty to IfcLabel.
Instantiation changed to OPTIONAL.
      DescriptionXXMODIFIEDName changed from DependantProperty to Description.
Type changed from IfcProperty to IfcText.
Instantiation changed to OPTIONAL.
      DependingPropertyXXMODIFIEDName changed from Name to DependingProperty.
Type changed from IfcLabel to IfcProperty.
Instantiation changed from OPTIONAL.
      DependantPropertyXXMODIFIEDName changed from Description to DependantProperty.
Type changed from IfcText to IfcProperty.
Instantiation changed from OPTIONAL.
Semantic definitions at the entity
Entity definition

An IfcPropertyDependencyRelationship describes an identified dependency between the value of one property and that of another.

HISTORY  New entity in IFC2x2

IFC4 CHANGE  Made subtype of IfcResourceLevelRelationship (attribute order changed).

Use Definition

Whilst the IfcPropertyDependencyRelationship may be used to describe the dependency, and it may do so in terms of the expression of how the dependency operates, it is not possible through the current IFC model for the value of the related property to be actually derived from the value of the relating property. The determination of value according to the dependency is required to be performed by an application that can then use the Expression attribute to flag the form of the dependency.

Attribute definitions
#AttributeTypeCardinalityDescription G
3DependingPropertyIfcProperty The property on which the relationship depends. X
4DependantPropertyIfcProperty The dependant property. X
5ExpressionIfcText? Expression that further describes the nature of the dependency relation. X
Formal Propositions
RuleDescription
NoSelfReferenceThe DependingProperty shall not point to the same instance as the DependantProperty.
Inherited definitions from supertypes
Entity inheritance IfcResourceLevelRelationship
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcResourceLevelRelationship
1NameIfcLabel? A name used to identify or qualify the relationship. X
2DescriptionIfcText? A description that may apply additional information about the relationship. X
IfcPropertyDependencyRelationship
3DependingPropertyIfcProperty The property on which the relationship depends. X
4DependantPropertyIfcProperty The dependant property. X
5ExpressionIfcText? Expression that further describes the nature of the dependency relation. X
Formal representations
XML Specification
 <xs:element name="IfcPropertyDependencyRelationship" type="ifc:IfcPropertyDependencyRelationship" substitutionGroup="ifc:IfcResourceLevelRelationship" nillable="true"/>
 <xs:complexType name="IfcPropertyDependencyRelationship">
  <xs:complexContent>
   <xs:extension base="ifc:IfcResourceLevelRelationship">
    <xs:sequence>
     <xs:element name="DependingProperty" type="ifc:IfcProperty" nillable="true"/>
     <xs:element name="DependantProperty" type="ifc:IfcProperty" nillable="true"/>
    </xs:sequence>
    <xs:attribute name="Expression" type="ifc:IfcText" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcPropertyDependencyRelationship
 SUBTYPE OF (IfcResourceLevelRelationship);
  DependingProperty : IfcProperty;
  DependantProperty : IfcProperty;
  Expression : OPTIONAL IfcText;
 WHERE
  NoSelfReference : DependingProperty :<>: DependantProperty;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcProperty

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