5.1.3.46 IfcTypeObject
5.1.3.46.1 Semantic 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 - occurrence modeling paradigm. The IfcTypeObject gets assigned to the individual object instances (the occurrences) via the IfcRelDefinesByType relationship.
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.
If a property 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.
New entity in IFC2x The IfcTypeObject is now subtyped from the new supertype IfcObjectDefinition, and the attribute HasPropertySets has been changed from a LIST into a SET. 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.5.1.3.46.2 Entity inheritance
5.1.3.46.3 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, Only the last modification is stored - either as addition, deletion or modification. The attribute has been changed to be OPTIONAL. |
| 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. |
| IfcObjectDefinition (7) | |||
| HasAssignments | SET [0:?] OF IfcRelAssigns FOR RelatedObjects |
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. |
|
| Nests | SET [0:1] OF IfcRelNests FOR RelatedObjects |
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 structures only). The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition. |
|
| IsNestedBy | SET [0:?] OF IfcRelNests FOR RelatingObject |
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). The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition. |
|
| HasContext | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions |
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. The inverse attribute datatype has been added. |
|
| IsDecomposedBy | SET [0:?] OF IfcRelAggregates FOR RelatingObject |
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 definition can be aggregated by several other objects (occurrences or parts). The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. |
|
| Decomposes | SET [0:1] OF IfcRelAggregates FOR RelatedObjects |
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 definition can only be part of a single decomposition (to allow hierarchical structures only). The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. |
|
| HasAssociations | SET [0:?] OF IfcRelAssociates FOR RelatedObjects |
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. |
|
| Click to show 11 hidden inherited attributes Click to hide 11 inherited attributes | |||
| IfcTypeObject (3) | |||
| 5 | ApplicableOccurrence | OPTIONAL IfcIdentifier |
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:
|
| 6 | HasPropertySets | OPTIONAL SET [1:?] OF IfcPropertySetDefinition |
Set of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type. The attribute aggregate type has been changed from LIST to SET. |
| Types | SET [0:1] OF IfcRelDefinesByType FOR RelatingType |
Reference to the relationship IfcRelDefinesByType and thus to those occurrence objects, which are defined by this type. |
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5.1.3.46.4 Formal propositions
| Name | Description |
|---|---|
| NameRequired |
A Name attribute has to be provided. The name can be declared within the IFC specification as part of the property set agreements. |
|
|
| UniquePropertySetNames |
Every individual IfcPropertySetDefinition assigned to the instance in the attribute HasPropertySets shall have a unique Name attribute value. |
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5.1.3.46.5 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. |
|
| IfcObjectDefinition (9) | |||
| Classification Association | General |
Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system. |
|
| Aggregation | General |
No description available. |
|
| Approval Association | General |
No description available. |
|
| Constraint Association | General |
No description available. |
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| Document Association | General |
No description available. |
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| Library Association | General |
No description available. |
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| Material Association | General |
No description available. |
|
| Material Single | General |
No description available. |
|
| Nesting | General |
No description available. |
|
| Click to show 11 hidden inherited concepts Click to hide 11 inherited concepts | |||
| IfcTypeObject (2) | |||
| Object Type Predefined Type | General |
No description available. |
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| Property Sets for Types | General |
No description available. |
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5.1.3.46.6 Formal representation
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;