IFC (IFC4X3_ADD2) under development IfcSimplePropertyTemplate Semantic definition

The IfcSimplePropertyTemplate defines the template for all dynamically extensible properties, either the subtypes of IfcSimpleProperty, or the subtypes of IfcPhysicalSimpleQuantity. The individual property templates are interpreted according to their Name attribute and may have a predefined template type, property units, and property measure types. The correct interpretation of the attributes:

  • PrimaryUnit
  • SecondaryUnit
  • PrimaryMeasureType
  • SecondaryMeasureType

is determined by the TemplateType. The attributes Enumerators and Expression only apply to instances of IfcSimplePropertyTemplate having a particular TemplateType. The TemplateType also controls which subtype of either IfcSimpleProperty or IfcPhysicalSimpleQuantity shall be used for property occurrences corresponding to this template.

The IfcSimplePropertyTemplate is part of the set of templates included in the IfcPropertySetTemplate. The template can be accessed through the inverse attribute PartOfPsetTemplate The IfcPropertySetTemplate may define one or several instances of IfcPropertySet (or IfcElementQuantity). The definition assignment is established by the objectified relationship IfcRelDefinesByTemplate as shown in Figure There is no direct link between an IfcSimplePropertyTemplate and a subtype of either IfcSimpleProperty or IfcPhysicalSimpleQuantity. The definition relationship between the template and the individual properties (or quantities) is established by the Name attributes.

IfcSimplePropertyTemplate figure 1
Figure — Property template relationships Entity inheritance Attributes

# Attribute Type Description
IfcRoot (4)
1 GlobalId IfcGloballyUniqueId

Assignment of a globally unique identifier within the entire software world.

2 OwnerHistory OPTIONAL IfcOwnerHistory

Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object,

3 Name OPTIONAL IfcLabel

Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.

4 Description OPTIONAL IfcText

Optional description, provided for exchanging informative comments.

IfcPropertyDefinition (2)
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions

Reference to the relationship IfcRelDeclares and thus to the IfcProject or IfcProjectLibrary.

HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects

Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition.

IfcPropertyTemplate (2)
PartOfComplexTemplate SET [0:?] OF IfcComplexPropertyTemplate FOR HasPropertyTemplates

Reference to a complex property template. It should only be provided, if the PropertyType of the referenced complex property template is set to COMPLEX.

PartOfPsetTemplate SET [0:?] OF IfcPropertySetTemplate FOR HasPropertyTemplates

Reference to the IfcPropertySetTemplate that defines the scope for the IfcPropertyTemplate. A single IfcPropertyTemplate can be defined within the scope of zero, one or many IfcPropertySetTemplate entities.

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IfcSimplePropertyTemplate (8)
5 TemplateType OPTIONAL IfcSimplePropertyTemplateTypeEnum

Property type defining whether the property template defines a property with a single value, a bounded value, a list value, a table value, an enumerated value, or a reference value. Or the quantity type defining whether the template defines a quantity with a length, area, volume, weight or time value.

6 PrimaryMeasureType OPTIONAL IfcLabel

Primary measure type assigned to the definition of the property. It should be provided, if the TemplateType is set to:

7 SecondaryMeasureType OPTIONAL IfcLabel

Secondary measure type assigned to the definition of the property. It should be provided, if the TemplateType is set to:

The value range of the measure type is within the select type IfcValue for all TemplateType's with the exception of P_ENUMERATEDVALUE. Here it is the comma delimited list of enumerators.

8 Enumerators OPTIONAL IfcPropertyEnumeration

Name of the property enumeration, and list of all valid enumerators being selectable values, assigned to the definition of the property. This attribute shall only be provided, if the TemplateType is set to:

9 PrimaryUnit OPTIONAL IfcUnit

Primary unit assigned to the definition of the property. It should be provided, if the TemplateType is set to:

10 SecondaryUnit OPTIONAL IfcUnit

Secondary unit assigned to the definition of the property. It should be provided, if the TemplateType is set to:

11 Expression OPTIONAL IfcLabel

The expression used to store additional information for the property template depending on the TemplateType. It should provide the following definitions, if the TemplateType is set to:

  • P_TABLEVALUE: the expression that could be evaluated to define the correlation between the defining values and the defined values.
  • Q_LENGTH, Q_AREA, Q_VOLUME, Q_COUNT, Q_WEIGTH, Q_TIME: the formula to be used to calculate the quantity
12 AccessState OPTIONAL IfcStateEnum

Information about the access state of the property. It determines whether a property can be viewed and/or modified by any receiving application without specific knowledge of it.

Attribute use definition for IfcStateEnum

  • READWRITE: Properties of this template are readable and writable. They may be viewed and modified by users of any application. These are typical informational properties set by a user.
  • READONLY: Properties of this template are read-only. They may be viewed but not modified by users of any application. (Applications may generate such values). These are typical automatically generated properties that should be displayed only, but not written back.
  • LOCKED: Properties of this template are locked. They may only be accessed by the owning application (the publisher of the property set template). These are typically application dependent, internal properties that should not be published.
  • READWRITELOCKED: Properties of this template are locked, readable, and writable. They may only be accessed by the owning application.
  • READONLYLOCKED: Properties of this template are locked and read-only. They may only be accessed by the owning application.
Table Concept usage

Concept Usage Description
IfcRoot (2)
Revision Control General

Ownership, history, and merge state is captured using IfcOwnerHistory.

Software Identity General

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

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Table Formal representation

ENTITY IfcSimplePropertyTemplate
 SUBTYPE OF (IfcPropertyTemplate);
	TemplateType : OPTIONAL IfcSimplePropertyTemplateTypeEnum;
	PrimaryMeasureType : OPTIONAL IfcLabel;
	SecondaryMeasureType : OPTIONAL IfcLabel;
	Enumerators : OPTIONAL IfcPropertyEnumeration;
	PrimaryUnit : OPTIONAL IfcUnit;
	SecondaryUnit : OPTIONAL IfcUnit;
	Expression : OPTIONAL IfcLabel;
	AccessState : OPTIONAL IfcStateEnum;
END_ENTITY; References

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