IfcMetric

BACnet MVD

#### IfcMetric

Natural language names

| Metrik
| Metric
| Métrique

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcMetric |  |  |  |
CreationTime | X | X | MODIFIED | Type changed from IfcDateTimeSelect to IfcDateTime.
ReferencePath |  |  | ADDED |
IFC4 Addendum 1
IfcMetric |  |  |  |
DataValue |  |  | MODIFIED | Instantiation changed to OPTIONAL.
PropertiesForConstraint |  |  | ADDED |
ConstrainedResources |  |  | DELETED |
ConstrainedObjects |  |  | DELETED |

##### Semantic definitions at the entity

Entity definition

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.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
8 | Benchmark | IfcBenchmarkEnum |  | Enumeration that identifies the type of benchmark data. |  | X
9 | ValueSource | IfcLabel | ? | Reference source for data values. If DataValue refers to an IfcTable, this attribute identifies the relevent column identified by IfcTableColumn.Identifier. |  | X

10

DataValue

IfcMetricValueSelect

?

The value to be compared on associated objects. A null value indicates comparison to null.

> IFC4 ADD1 CHANGE This attribute is now optional.

X

11 | ReferencePath | IfcReference | ? | 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. |  | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcConstraint
1 | Name | IfcLabel |  | A human-readable name to be used for the constraint. |  | X
2 | Description | IfcText | ? | A human-readable description that may apply additional information about a constraint. |  | X
3 | ConstraintGrade | IfcConstraintEnum |  | Enumeration that qualifies the type of constraint. |  | X
4 | ConstraintSource | IfcLabel | ? | Any source material, such as a code or standard, from which the constraint originated. |  | X
5 | CreatingActor | IfcActorSelect | ? | Person and/or organization that has created the constraint. |  | X
6 | CreationTime | IfcDateTime | ? | Time when information specifying the constraint instance was created. |  | X
7 | UserDefinedGrade | IfcLabel | ? | Allows for specification of user defined grade of the constraint beyond the enumeration values (hard, soft, advisory) provided by ConstraintGrade attribute of type IfcConstraintEnum. When a value is provided for attribute UserDefinedGrade in parallel the attribute ConstraintGrade shall have enumeration value USERDEFINED. |  | X

HasExternalReferences

IfcExternalReferenceRelationship
@RelatedResourceObjects

S[0:?]

Reference to an external references, e.g. library, classification, or document information, that are associated to the constraint.

> IFC4 CHANGE New inverse attribute.

X

| PropertiesForConstraint | IfcResourceConstraintRelationship @RelatingConstraint | S[0:?] | Reference to the properties to which the constraint is applied. |  | X
IfcMetric
8 | Benchmark | IfcBenchmarkEnum |  | Enumeration that identifies the type of benchmark data. |  | X
9 | ValueSource | IfcLabel | ? | Reference source for data values. If DataValue refers to an IfcTable, this attribute identifies the relevent column identified by IfcTableColumn.Identifier. |  | X

10

DataValue

IfcMetricValueSelect

?

The value to be compared on associated objects. A null value indicates comparison to null.

> IFC4 ADD1 CHANGE This attribute is now optional.

X

11 | ReferencePath | IfcReference | ? | 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. |  | X

##### Formal representations

XML 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" nillable="true" minOccurs="0">
<xs:complexType>
<xs:group ref="ifc:IfcMetricValueSelect"/>
</xs:complexType>
</xs:element>
<xs:element name="ReferencePath" type="ifc:IfcReference" nillable="true" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="Benchmark" type="ifc:IfcBenchmarkEnum" use="optional"/>
<xs:attribute name="ValueSource" type="ifc:IfcLabel" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcMetric
SUBTYPE OF (IfcConstraint);
Benchmark : IfcBenchmarkEnum;
ValueSource : OPTIONAL IfcLabel;
DataValue : OPTIONAL IfcMetricValueSelect;
ReferencePath : OPTIONAL IfcReference;
END_ENTITY;

EXPRESS-G diagram

`

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