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IfcAppliedValueRelationship

Definition from IAI: An IfcAppliedValueRelationship is a relationship class that enables applied values of cost or environmental impact to be aggregated together as components of another applied value.

HISTORY: New Entity in IFC Release 2.0. Name changed in IFC 2x2 from IfcCostValueRelationship.

Use Definitions

Dependency relationships can exist between applied values on the basis that one particular value may be determined by operations on one or more other values. This is captured through the IfcAppliedValueRelationship entity. In this relationship, one instance of IfcAppliedValue acts as the principal (IfcAppliedValueRelationship.ComponentOf) whose value may be determined from the instances of IfcAppliedValue that are defined as its components (IfcAppliedValueRelationship.Components)

An IfcAppliedValueRelationship has an ArithmeticOperator attribute that specifies the form of arithmetical operation implied by the relationship.

A practical consideration when using the applied value relationship is that when the arithmetic operator is ADD, then the type of the IfcAppliedValue.AppliedValue attribute will be IfcMeasureWithUnit or IfcMonetaryMeasure whilst if the arithmetic operator is MULTIPLY, then the type of the IfcAppliedValue.AppliedValue attribute for one instance of IfcAppliedValue will be IfcMeasureWithUnit or IfcMonetaryMeasure whilst for other instances it will be IfcRatioMeasure.

Example

A relationship exists between applied value A and applied values B, C and D such that the value of A is determined by the addition of B, C and D such that:

A = B + C + D

Adding Applied Values

It is possible to develop more complex applied value specifications by creating hierarchies of applied value relationships. In the diagram below, the development of a applied value is shown whereby, because B = E * F and D = G * H * J, then:

A = ((E * F) + C + (G * H * J))

AddMultiply Applied Values

EXPRESS specification:

ENTITY IfcAppliedValueRelationship;
ComponentOfTotal  :  IfcAppliedValue;
Components  :  SET [1:?] OF IfcAppliedValue;
ArithmeticOperator  :  IfcArithmeticOperatorEnum;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
END_ENTITY;

Attribute definitions:

ComponentOfTotal  :  The applied value (total or subtotal) of which the value being considered is a component.
Components  :  Applied values that are components of another applied value and from which that applied value may be deduced.
ArithmeticOperator  :  The arithmetic operator applied in an applied value relationship.
Name  :  A name used to identify or qualify the applied value relationship.
Description  :  A description that may apply additional information about an applied value relationship.

Inheritance graph

ENTITY IfcAppliedValueRelationship;
ENTITY IfcAppliedValueRelationship;
ComponentOfTotal  :  IfcAppliedValue;
Components  :  SET [1:?] OF IfcAppliedValue;
ArithmeticOperator  :  IfcArithmeticOperatorEnum;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
END_ENTITY;