Propriété à valeur simple
Merkmal mit Einzelwert

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 overriden by assigning an Unit.

The unit is handled by the Unit attribute, see Table 692 for an example of various single value properties:


Name NominalValue Type (through IfcValue) Unit
Description Manufacturer "A" door IfcLabel -
PanelThickness 0.12 IfcPositiveLengthMeasure -
ThermalTransmittance 2.6 IfcThermalTransmittanceMeasure W/(m2K)

Table 692 — Single value properties with values, measure types and units

HISTORY  New entity in IFC1.0.
IFC2x CHANGE  Entity has been renamed from IfcSimpleProperty.
IFC2x3 CHANGE  Attribute NominalValue has been made OPTIONAL with upward compatibility for file based exchange.

XSD Specification:

 <xs:element name="IfcPropertySingleValue" type="ifc:IfcPropertySingleValue" substitutionGroup="ifc:IfcSimpleProperty" nillable="true"/>
 <xs:complexType name="IfcPropertySingleValue">
   <xs:extension base="ifc:IfcSimpleProperty">
     <xs:element name="NominalValue" nillable="true" minOccurs="0">
       <xs:group ref="ifc:IfcValue"/>
     <xs:element name="Unit" nillable="true" minOccurs="0">
       <xs:group ref="ifc:IfcUnit"/>

EXPRESS Specification:

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

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

NominalValue : Value and measure type of this property.
NOTE  By virtue of the defined data type, that is selected from the SELECT IfcValue, the appropriate unit can be found within the IfcUnitAssignment, defined for the project if no value for the unit attribute is given.
IFC2x3 CHANGE  The attribute has been made optional with upward compatibility for file based exchange.
Unit : 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.

Inheritance Graph:

ENTITY IfcPropertySingleValue
ENTITY IfcPropertyAbstraction
HasExternalReferences : SET OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
ENTITY IfcProperty
Name : IfcIdentifier;
Description : OPTIONAL IfcText;
PartOfPset : SET OF IfcPropertySet FOR HasProperties;
PropertyForDependance : SET OF IfcPropertyDependencyRelationship FOR DependingProperty;
PropertyDependsOn : SET OF IfcPropertyDependencyRelationship FOR DependantProperty;
PartOfComplex : SET OF IfcComplexProperty FOR HasProperties;
ENTITY IfcSimpleProperty
ENTITY IfcPropertySingleValue
NominalValue : OPTIONAL IfcValue;
Unit : OPTIONAL IfcUnit;

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