IfcTypeObject

Natural language names
deObjekt (allgemein) - Typ
enType Object
frDéfinition d'un type d'objet type
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcTypeObject
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
      ApplicableOccurrenceMODIFIEDType changed from IfcLabel to IfcIdentifier.
Semantic definitions at the entity
Entity definition

The object type defines the specific information about a type, being common to all occurrences of this type. It refers to the specific level of the well recognized generic - specific - occurrance modeling paradigm. The IfcTypeObject gets assigned to the individual object instances (the occurrences) via the IfcRelDefinesByType relationship.

NOTE  The terms 'Type' and 'Style' are often used interchangeably.

The object type is represented by a set of property set definitions. The attached property sets describe the available alpha-numeric information about the object type. and are used to define all common properties that apply to all object occurrences of that type.

NOTE  If a property having having the same name is used within the IfcPropertySet assigned to an IfcTypeObject (and subtypes) and to an occurrence of that type, then the occurrence property overrides the type property. See IfcRelDefinesByType for an explanatory figure.

Object types may be exchanged without being already assigned to objects. An object type may have an indication of the library (or catalogue) from which its definition originates. This association is handled by the inherited HasAssociations relationship pointing to IfcRelAssociatesLibrary.

HISTORY  New entity in IFC2x
IFC2x3 CHANGE  The IfcTypeObject is now subtyped from the new supertype IfcObjectDefinition, and the attribute HasPropertySets has been changed from a LIST into a SET.
IFC4 CHANGE  The entity IfcTypeObject shall not be instantiated from IFC4 onwards. It will be changed into an ABSTRACT supertype in future releases of IFC. The inverse attribute Types has been renamed from ObjectTypeOf.
Attribute definitions
#AttributeTypeCardinalityDescription C
5ApplicableOccurrenceIfcIdentifier[0:1] The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used:
  • The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix
  • It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase
  • If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string.
EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.
X
6HasPropertySetsIfcPropertySetDefinitionS[1:?] Set list of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type. X
TypesIfcRelDefinesByType
@RelatingType		S[0:1]Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.X
Formal Propositions
RuleDescription
NameRequiredA Name attribute has to be provided. The name can be declared within the IFC specification as part of the property set agreements.
UniquePropertySetNames
Inherited definitions from supertypes
Entity inheritance IfcTypeProcess IfcTypeProduct IfcTypeResource IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionC
IfcRoot
1GlobalIdIfcGloballyUniqueId[1:1] Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory[0:1] 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.
X
3NameIfcLabel[0:1] 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
4DescriptionIfcText[0:1] Optional description, provided for exchanging informative comments.X
IfcObjectDefinition
HasAssignmentsIfcRelAssigns
@RelatedObjects		S[0:?]Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.X
NestsIfcRelNests
@RelatedObjects		S[0:1]References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only). X
IsNestedByIfcRelNests
@RelatingObject		S[0:?]References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types). X
HasContextIfcRelDeclares
@RelatedDefinitions		S[0:1]References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object. X
IsDecomposedByIfcRelAggregates
@RelatingObject		S[0:?]References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts). X
DecomposesIfcRelAggregates
@RelatedObjects		S[0:1]References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only). X
HasAssociationsIfcRelAssociates
@RelatedObjects		S[0:?]Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.X
IfcTypeObject
5ApplicableOccurrenceIfcIdentifier[0:1] The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used:
  • The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix
  • It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase
  • If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string.
EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.
X
6HasPropertySetsIfcPropertySetDefinitionS[1:?] Set list of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type. X
TypesIfcRelDefinesByType
@RelatingType		S[0:1]Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.X
Definitions applying to Common Use Definitions
Concept inheritance

#ConceptModel View
IfcRoot
Software IdentityCommon Use Definitions
Revision ControlCommon Use Definitions
Formal representations
XSD Specification
 <xs:element name="IfcTypeObject" type="ifc:IfcTypeObject" substitutionGroup="ifc:IfcObjectDefinition" nillable="true"/>
 <xs:complexType name="IfcTypeObject">
  <xs:complexContent>
   <xs:extension base="ifc:IfcObjectDefinition">
    <xs:sequence>
     <xs:element name="HasPropertySets" nillable="true" minOccurs="0">
      <xs:complexType>
       <xs:sequence>
        <xs:element ref="ifc:IfcPropertySetDefinition" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcPropertySetDefinition"/>
       <xs:attribute ref="ifc:cType" fixed="set"/>
       <xs:attribute ref="ifc:arraySize" use="optional"/>
      </xs:complexType>
     </xs:element>
    </xs:sequence>
    <xs:attribute name="ApplicableOccurrence" type="ifc:IfcIdentifier" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcTypeObject
 SUPERTYPE OF(ONEOF(IfcTypeProcess, IfcTypeProduct, IfcTypeResource))
 SUBTYPE OF (IfcObjectDefinition);
  ApplicableOccurrence : OPTIONAL IfcIdentifier;
  HasPropertySets : OPTIONAL SET [1:?] OF IfcPropertySetDefinition;
 INVERSE
  Types : SET [0:1] OF IfcRelDefinesByType FOR RelatingType;
 WHERE
  NameRequired : EXISTS(SELF\IfcRoot.Name);
  UniquePropertySetNames : (NOT(EXISTS(HasPropertySets))) OR IfcUniquePropertySetNames(HasPropertySets);
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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