IFC 4.3.x development

8.16.3.10 IfcPropertyListValue

Change log

IFC4

modificationsattributes ListValues is_optionalChanged from False to True

8.16.3.10.1 Semantic definitions at the entity

An IfcPropertyListValue defines a property that has several (numeric or descriptive) values assigned, these values are given by an ordered list. It defines a property - list value combination for which the property Name, an optional Description, the optional ListValues with measure type and optionally an Unit is given. An IfcPropertyListValue is a list of values. The order in which values appear is significant. All list members shall be of the same type.

The unit is handled by the Unit attribute, see Table 1 for an example of a list property:

  • 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.

NOTE  An IfcPropertyListValue may be exchanged with no values assigned yet. In this case the ListValues are set to NIL.

 

Name
ListValues Type
(through IfcValue)
Unit

<tr>
 <td width="15%">ApplicableSizes</td>
 <td width="30%">1200</td>
 <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
 <td width="30%">-</td>
</tr>
<tr>
 <td width="15%">-</td>
 <td width="30%">1600</td>
 <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
 <td width="30%">-</td>
</tr>
<tr>
 <td width="15%">-</td>
 <td width="30%">2400</td>
 <td width="25%"><em>IfcPositiveLengthMeasure</em></td>
 <td width="30%">-</td>
</tr>

Table 1 — List property with values, measure types and units

HISTORY  New entity in IFC2x2.

IFC4 CHANGE  Attribute ListValues has been made OPTIONAL with upward compatibility for file based exchange.

8.16.3.10.1 Attributes

# Attribute Type Description
IfcPropertyAbstraction
HasExternalReferencesSET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition.

> IFC4 CHANGE New inverse attribute.
IfcProperty
1 Name IfcIdentifier Name for this property. This label is the significant name string that defines the semantic meaning for the property.
2 Description OPTIONAL IfcText Informative text to explain the property.
PartOfPset SET [0:?] OF IfcPropertySet FOR HasProperties Reference to the IfcPropertySet by which the IfcProperty is referenced.

> IFC4 CHANGE  New inverse attribute to navigate from IfcProperty to IfcPropertySet with upward compatibility for file based exchange.
PropertyForDependanceSET [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.

> IFC4 CHANGE  The cardinality has changed to 0..n to allow reuse of instances of IfcProperty in several IfcComplexProperty with upward compatibility for file based exchange.
HasConstraints SET [0:?] OF IfcResourceConstraintRelationship FOR RelatedResourceObjectsUser-defined constraints for the property.
HasApprovals SET [0:?] OF IfcResourceApprovalRelationship FOR RelatedResourceObjects User-defined approvals for the property.
IfcSimpleProperty
IfcPropertyListValue
3 ListValues OPTIONAL LIST [1:?] OF IfcValue List of property values.

> IFC4 CHANGE  The attribute has been made optional with upward compatibility for file based exchange.
4 Unit OPTIONAL IfcUnit Unit for the list values, 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.

8.16.3.10.2 Entity inheritance

dot_inheritance IfcPropertyListValue IfcPropertyListValue IfcSimpleProperty IfcSimpleProperty IfcPropertyListValue->IfcSimpleProperty IfcSimpleProperty_children 5 more... IfcSimpleProperty_children->IfcSimpleProperty IfcProperty IfcProperty IfcSimpleProperty->IfcProperty IfcComplexProperty IfcComplexProperty IfcComplexProperty->IfcProperty IfcPropertyAbstraction IfcPropertyAbstraction IfcProperty->IfcPropertyAbstraction IfcPropertyAbstraction_children 3 more... IfcPropertyAbstraction_children->IfcPropertyAbstraction

8.16.3.10.3 Formal representations

ENTITY IfcPropertyListValue
 SUBTYPE OF (IfcSimpleProperty);
	ListValues : OPTIONAL LIST [1:?] OF IfcValue;
	Unit : OPTIONAL IfcUnit;
 WHERE
	WR31 : SIZEOF(QUERY(temp <* SELF.ListValues | 
  NOT(TYPEOF(SELF.ListValues[1]) = TYPEOF(temp))
  )) = 0;
END_ENTITY;