# 8.16.3.7 IfcPropertyDependencyRelationship

## 8.16.3.7.1 Semantic definition

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

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.

## 8.16.3.7.5 Formal representation

ENTITY IfcPropertyDependencyRelationship
SUBTYPE OF (IfcResourceLevelRelationship);
DependingProperty : IfcProperty;
DependantProperty : IfcProperty;
Expression : OPTIONAL IfcText;
WHERE
NoSelfReference : DependingProperty :<>: DependantProperty;
END_ENTITY;

## 8.16.3.7.6 References

### 8.16.3.7.7 Changelog

#### 8.16.3.7.7.1 IFC4

• where rule, NoSelfReference
• attribute, Description
• attribute, Name
• where rule, WR1