IfcPropertySet

BACnet MVD

#### IfcPropertySet

Natural language names

| frei definierbare Merkmalsliste
| Property Set
| Ensemble de propriétés

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcPropertySet |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity definition

The IfcPropertySet is a container that holds properties within a property tree. These properties are interpreted according to their name attribute. Each individual property has a significant name string. Some property sets are included in the specification of this standard and have a predefined set of properties indicated by assigning a significant name. These property sets are listed under "property sets" within this specification. Property sets applicable to certain objects are listed in the object specification. The naming convention "Pset_Xxx" applies to all those property sets that are defined as part of this specification and it shall be used as the value of the Name attribute.

In addition any user defined property set can be captured. Property sets that are not declared as part of the IFC specification shall have a Name value not including the "Pset_" prefix.

IfcPropertySet can be assigned to object occurrences and object types. An IfcPropertySet assigned to an object type is shared among all occurrences of the same object type.

> NOTE See IfcRelDefinesByType for how to override property sets assigned to an object type within the object occurrence.

An IfcPropertySetTemplate may define the underlying structure, i.e. the required name, the applicable object or object types to which the property set can be attached, and the individual properties that can be included. Property sets are related to other objects by using the relationship object that refers to the corresponding object:

- Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence.
- Type Object: using a direct link by inverse attribute DefinesType.
- Underlying template: IfcRelDefinesByTemplate using the inverse attribute IsDefinedBy.
- External reference: subtypes of IfcRelAssociates are used to provide a link to a classification system, or external library providing further reference to the property set. Accessible by inverse attribute HasAssociations.

> HISTORY New entity in IFC1.0

> IFC4 CHANGE All statically defined property set entities are no longer subtypes of IfcPropertySet.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
5 | HasProperties | IfcProperty | S[1:?] | Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time. | X | X

Formal Propositions

Rule | Description
--- | ---
ExistsName | The Name attribute has to be provided. The attribute is used to specify the signifier of the property set. The properties that are allowed to be attached to a particular property set may be given within the property set definition part of the IFC specification. Those property set definitions are references in the semantic definition section of the individal subtypes of IfcObjectDefinition.
UniquePropertyNames | Every individual subtype of IfcProperty within the property set shall have a unique Name attribute value.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | X

2

OwnerHistory

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,

> NOTE only the last modification in stored - either as addition, deletion or modification.

> IFC4 CHANGE The attribute has been changed to be OPTIONAL.

X

X

3 | Name | 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. | X | X
4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. |  | X
IfcPropertyDefinition
| HasContext | IfcRelDeclares @RelatedDefinitions | S[0:1] |  |  | X
| HasAssociations | IfcRelAssociates @RelatedObjects | S[0:?] | 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. |  | X
IfcPropertySetDefinition

DefinesType

IfcTypeObject
@HasPropertySets

S[0:?]

The type object to which the property set is assigned. The property set acts as a shared property set to all occurrences of the type object.

> NOTE The relationship between the IfcPropertySetDefinition and the IfcTypeObject is a direct relationship, not utilizing IfcRelDefinesByProperties, for maintaining compatibility with earlier releases of this standard.

> IFC4 CHANGE The cardinality has been changed from 0:1 to 0:? with upward compatibility for file based exchange.

X

IsDefinedBy

IfcRelDefinesByTemplate
@RelatedPropertySets

S[0:?]

Relation to the property set template, via the objectified relationship IfcRelDefinesByTemplate, that, if given, provides the definition template for the property set or quantity set and its properties.

> IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange.

X

DefinesOccurrence

IfcRelDefinesByProperties
@RelatingPropertyDefinition

S[0:?]

Reference to the relation to one or many object occurrences that are characterized by the property set definition. A single property set can be assigned to multiple object occurrences using the objectified relationship IfcRefDefinesByProperties.

> IFC4 CHANGE Inverse attribute renamed from PropertyDefinitionOf with upward compatibility for file-based exchange.

X

IfcPropertySet
5 | HasProperties | IfcProperty | S[1:?] | Contained set of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the set of predefined properties, its value has not been set at this time. | X | X

##### Definitions applying to Design Transfer View

Instance diagram

#####

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Examples

- Air terminal element

##### Formal representations

XML Specification
`<xs:element name="IfcPropertySet" type="ifc:IfcPropertySet" substitutionGroup="ifc:IfcPropertySetDefinition" nillable="true"/>
<xs:complexType name="IfcPropertySet">
<xs:complexContent>
<xs:extension base="ifc:IfcPropertySetDefinition">
<xs:sequence>
<xs:element name="HasProperties">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcProperty" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcProperty"/>
<xs:attribute ref="ifc:cType" fixed="set"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPropertySet
SUBTYPE OF (IfcPropertySetDefinition);
HasProperties : SET [1:?] OF IfcProperty;
WHERE
ExistsName : EXISTS(SELF\IfcRoot.Name);
UniquePropertyNames : IfcUniquePropertyName(HasProperties);
END_ENTITY;

EXPRESS-G diagram

`

References: IfcProperty

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