#### 8.2.3.2 IfcMetric

| Métrique
| Metrik

An IfcMetric is used to capture quantitative resultant metrics that can be applied to objectives.

IfcMetric is a subtype of IfcConstraint and may be associated with any subtype of IfcRoot through the IfcRelAssociatesConstraint relationship in the IfcControlExtension schema, or may be associated with IfcProperty by IfcResourceConstraintRelationship.

The aim of IfcMetric is to capture the quantitative aspects of a constraint.

> HISTORY New entity in IFC2.0.

> IFC4 CHANGE ReferencePath attribute added for indicating the value to be constrained along a path of attribute references.

> XSD Specification:

> <xs:element name="IfcMetric" type="ifc:IfcMetric" substitutionGroup="ifc:IfcConstraint" nillable="true"/>
> <xs:complexType name="IfcMetric">
> <xs:complexContent>
> <xs:extension base="ifc:IfcConstraint">
> <xs:sequence>
> <xs:element name="DataValue">
> <xs:complexType>
> <xs:group ref="ifc:IfcMetricValueSelect"/>
> </xs:complexType>
> </xs:element>
> </xs:sequence>
> <xs:attribute name="Benchmark" type="ifc:IfcBenchmarkEnum" use="optional"/>
> </xs:extension>
> </xs:complexContent>
> </xs:complexType>

> EXPRESS Specification:

> ENTITY IfcMetric

> | SUBTYPE OF (IfcConstraint);

> Benchmark | : | IfcBenchmarkEnum;
> ValueSource | : | OPTIONAL IfcStrippedOptional;
> DataValue | : | IfcMetricValueSelect;
> ReferencePath | : | OPTIONAL IfcStrippedOptional;

> END_ENTITY;

> Attribute Definitions:

> Benchmark | : | Enumeration that identifies the type of benchmark data.
> ValueSource | : | Reference source for data values. If DataValue refers to an IfcTable, this attribute identifies the relevent column identified by IfcTableColumn.Name.
> DataValue | : | The value to be compared on associated objects.
> ReferencePath | : | Optional path to an attribute to be constrained on associated objects. If provided, the metric may be validated by resolving the path to the current value on associated object(s), and comparing such value with DataValue according to the Benchmark.

> Inheritance Graph:

> ENTITY IfcMetric

> | ENTITY IfcConstraint

> Name | : | IfcLabel;
> Description | : | OPTIONAL IfcStrippedOptional;
> ConstraintGrade | : | IfcConstraintEnum;
> ConstraintSource | : | OPTIONAL IfcStrippedOptional;
> CreatingActor | : | OPTIONAL IfcStrippedOptional;
> CreationTime | : | OPTIONAL IfcStrippedOptional;
> UserDefinedGrade | : | OPTIONAL IfcStrippedOptional;

> | INVERSE

> | ENTITY IfcMetric

> Benchmark | : | IfcBenchmarkEnum;
> ValueSource | : | OPTIONAL IfcStrippedOptional;
> DataValue | : | IfcMetricValueSelect;
> ReferencePath | : | OPTIONAL IfcStrippedOptional;

> END_ENTITY;

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