#### 5.1.3.36 IfcSimplePropertyTemplate

| Modèle de propriété simple
| Einfaches Merkmal - Vorlage

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.

> HISTORY New entity in IFC4.

Relationship use definition

The IfcSimplePropertyTemplate is part of the set of templates included in the IfcPropertySetTemplate. The template can be accessed throught 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 40.

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.

> NOTE Constraints at IfcPropertySetTemplate and IfcPropertySet (and IfcElementQuantity) guarantee that the Name attributes of included property templates and individual properties are unique.

Figure 40 — Property template relationships

## Building Automation

For objects that have specific properties, IFC provides an extensibility mechanism in the form of Property Sets. To describe the data types, value ranges, and other metadata, IFC provides Property Set Templates. Properties may describe characteristics of product types, as well as real-time values, function parameters, and event parameters on devices.

There are three fundamental types of property sets: Type-driven, Occurrence-driven, and Performance-driven. Type-driven properties describe state that is inherent to a product model and cannot be configured or changed at occurrences. Occurrence-driven properties describe state that may be customized at particular occurrences, but is not intended to change dynamically over time without human configuration. Performance-driven properties describe state that may change over time, potentially at millisecond intervals or less.

For building automation, performance-driven properties are used to capture sensed and controlled values, while occurrence-driven properties are used to capture configuration parameters. Performance-driven properties are always in the form of time series, indicating sequences of values at periodic or irregular intervals.

The IFC model allows property set templates to be defined independently of object types, to provide a generic extensibility mechanism. The model also allows for property set templates to be identified explicitly on specific product types, such that when instances are created then such data can be automatically instantiated. In such cases, a property set is directly linked to the product type, where any values provided indicate defaults.

Property set templates may be mapped to managed runtime environments such as Java or .NET where data may be synchronized between the IFC model and programmatic extensions. The IFC classification mechanism is used to uniquely identify programmatic elements according to namespace and type name.

The following concepts are inherited at supertypes:

- IfcRoot: Revision Control

Instance diagram

Identity

The Identity concept applies to this entity.

Property definitions are named according to the underlying protocol documentation, and typically consist of only ASCII-based alphanumeric characters starting with a letter and containing no spaces or other punctuation. Such naming restrictions allow identifiers to be referenced in programming languages.

Exchange |  |  |  |  |
--- | --- | --- | --- | --- | ---
Import |  |  |  |  |
Export |  |  |  |  |

XSD Specification:

<xs:element name="IfcSimplePropertyTemplate" type="ifc:IfcSimplePropertyTemplate" substitutionGroup="ifc:IfcPropertyTemplate" nillable="true"/>
<xs:complexType name="IfcSimplePropertyTemplate">
<xs:complexContent>
<xs:extension base="ifc:IfcPropertyTemplate"/>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

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;

EXPRESS-G diagram

Attribute Definitions:

TemplateType | : | 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. NOTE the value of this property determines the correct use of the PrimaryUnit, SecondaryUnit, PrimaryDataType, SecondaryDataType, and Expression attributes.
PrimaryMeasureType | : | Primary measure type assigned to the definition of the property. It should be provided, if the PropertyType is set to: P_SINGLEVALUE: determining the measure type of IfcPropertySingleValue.NominalValue P_ENUMERATEDVALUE: determining the measure type of IfcPropertyEnumeratedValue.EnumerationValues P_BOUNDEDVALUE: determining the measure type of IfcPropertyBoundedValue.LowerBoundValue P_LISTVALUE: determining the measure type of IfcPropertyListValue.ListValues P_TABLEVALUE: determining the measure type of IfcPropertyTableValue.DefiningValues P_REFERENCEVALUE: determining the measure type of IfcPropertyTableValue.PropertyReference NOTE The value range of the measure type is within the select type IfcValue for all PropertyType's with the exeption of P_REFERENCEVALUE. Here it is within the select type IfcObjectReferenceSelect.
SecondaryMeasureType | : | Secondary measure type assigned to the definition of the property. It should be provided, if the PropertyType is set to: P_BOUNDEDVALUE: determining the measure type of IfcPropertyBoundedValue.UpperBoundValue P_TABLEVALUE: determining the measure type of IfcPropertyTableValue.DefinedValues The value range of the measure type is within the select type IfcValue for all PropertyType's with the exeption of P_ENUMERATEDVALUE. Here it is the comma delimited list of enumerators. NOTE The measure type of IfcPropertyEnumeration.EnumerationValues is provided as PrimaryDataType.
Enumerators | : | 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 PropertyType is set to: P_ENUMERATEDVALUE
PrimaryUnit | : | Primary unit assigned to the definition of the property. It should be provided, if the PropertyType is set to: P_SINGLEVALUE: determining the IfcPropertySingleValue.Unit P_ENUMERATEDVALUE: determining the IfcPropertyEnumeration.Unit P_BOUNDEDVALUE: determining the IfcPropertyBoundedValue.Unit P_LISTVALUE: determining the IfcPropertyListValue.Unit P_TABLEVALUE: determining the IfcPropertyTableValue.DefiningUnit
SecondaryUnit | : | Secondary unit assigned to the definition of the property. It should be provided, if the PropertyType is set to: P_TABLEVALUE: determining the IfcPropertyTableValue.DefinedUnit
Expression | : | The expression used to store additional information for the property template depending on the PropertyType. It should the following definitions, if the PropertyType 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 NOTE No value shall be asserted if the PropertyType is not listed above.
AccessState | : | Information about the access state of the property. It determines whether a property 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 depended, 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.

Inheritance Graph:

ENTITY IfcSimplePropertyTemplate

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcPropertyDefinition

| INVERSE

HasContext | : | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;

| ENTITY IfcPropertyTemplateDefinition

| ENTITY IfcPropertyTemplate

| INVERSE

PartOfComplexTemplate | : | SET OF IfcComplexPropertyTemplate FOR HasPropertyTemplates;
PartOfPsetTemplate | : | SET OF IfcPropertySetTemplate FOR HasPropertyTemplates;

| ENTITY IfcSimplePropertyTemplate

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;

Examples:

- Air terminal library object

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