IFC 4.3.1.0 (IFC4X3_ADD1)

8.16.3.12 IfcPropertySingleValue

8.16.3.12.1 Semantic definition

The property with a single value IfcPropertySingleValue defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property Name, an optional Description, and an optional NominalValue with measure type is provided. In addition, the default unit as specified within the project unit context can be overridden by assigning an Unit.

The unit is handled by the Unit attribute, see Table 8.16.3.12.G for an example of various single value properties:

  • If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext).
  • If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit.
Name NominalValue Type (through IfcValue) Unit
Description Manufacturer "A" door IfcLabel -
PanelThickness 0.12 IfcPositiveLengthMeasure -
ThermalTransmittance 2.6 IfcThermalTransmittanceMeasure W/(m2K)
Table 8.16.3.12.G — Single value properties with values, measure types and units

8.16.3.12.2 Entity inheritance

8.16.3.12.3 Attributes

# Attribute Type Description
IfcPropertyAbstraction (1)
HasExternalReferences SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects

Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition.

IfcProperty (8)
1 Name IfcIdentifier

Name for this property. This label is the significant name string that defines the semantic meaning for the property.

2 Specification OPTIONAL IfcText

URI reference to a location with semantic definition or informative text to explain the property.

PartOfPset SET [0:?] OF IfcPropertySet FOR HasProperties

Reference to the IfcPropertySet by which the IfcProperty is referenced.

PropertyForDependance SET [0:?] OF IfcPropertyDependencyRelationship FOR DependingProperty

The property on whose value that of another property depends.

PropertyDependsOn SET [0:?] OF IfcPropertyDependencyRelationship FOR DependantProperty

The relating property on which the value of the property depends.

PartOfComplex SET [0:?] OF IfcComplexProperty FOR HasProperties

Reference to the IfcComplexProperty in which the IfcProperty is contained.

HasConstraints SET [0:?] OF IfcResourceConstraintRelationship FOR RelatedResourceObjects

User-defined constraints for the property.

HasApprovals SET [0:?] OF IfcResourceApprovalRelationship FOR RelatedResourceObjects

User-defined approvals for the property.

Click to show 9 hidden inherited attributes Click to hide 9 inherited attributes
IfcPropertySingleValue (2)
3 NominalValue OPTIONAL IfcValue

Value and measure type of this property.

4 Unit OPTIONAL IfcUnit

Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject.

Table 8.16.3.12.H

8.16.3.12.4 Examples

8.16.3.12.5 Formal representation

ENTITY IfcPropertySingleValue
 SUBTYPE OF (IfcSimpleProperty);
	NominalValue : OPTIONAL IfcValue;
	Unit : OPTIONAL IfcUnit;
END_ENTITY;

8.16.3.12.6 References