IfcPropertyDependencyRelationship

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

> HISTORY: New entity in Release IFC2x Edition 2

### Use Definition

While 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.

EXPRESS specification:

ENTITY IfcPropertyDependencyRelationship;
DependingProperty | : | IfcProperty;
DependantProperty | : | IfcProperty;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;
Expression | : | OPTIONAL IfcText;
WHERE
WR1 | : | DependingProperty :<>: DependantProperty;
END_ENTITY;

Attribute definitions:

DependingProperty | : | The property on which the relationship depends.
DependantProperty | : | The dependant property.
Name | : | Name of the relationship that provides additional meaning to the nature of the dependency.
Description | : | Additional description of the dependency.
Expression | : | Expression that further describes the nature of the dependency relation.

Formal Propositions:

WR1 | : | The DependingProperty shall not point to the same instance as the DependantProperty

Inheritance graph

ENTITY IfcPropertyDependencyRelationship;
ENTITY IfcPropertyDependencyRelationship;
DependingProperty | : | IfcProperty;
DependantProperty | : | IfcProperty;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;
Expression | : | OPTIONAL IfcText;
END_ENTITY;