 | Kontextinformation |
 | Context |
 | Contexte |
| Item | SPF | XML | Change | Description | IFC2x3 to IFC4 4.0.0.0 |
|---|---|---|---|---|
| IfcContext | ADDED | IFC2x3 to IFC4 4.0.0.0 | ||
| IfcContext | ADDED |
IfcContext is the generalization of a project context in which objects, type objects, property sets, and properties are defined. The IfcProject as subtype of IfcContext provides the context for all information on a construction project, it may include one or several IfcProjectLibrary's as subtype of IfcContext to register the included libraries for the project. A library of products that is referenced is declared within the IfcProjectLibrary as the context of that library.
Context definitions can be named, using the inherited Name attribute, which should be a user recognizable key or number for the context. The LongName can add a full name. Further explanations to the context can be given using the inherited Description attribute.
A Context is declared by the relationship object IfcRelDeclares that refers to the corresponding objects within the context. More specific relationships are introduced at the level of subtypes.
HISTORY New abstract entity in IFC4.
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| 5 | ObjectType | IfcLabel | ? |
The object type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes.
NOTE Subtypes of IfcContext do not introduce a PredefinedType attribute, therefore the usage of ObjectType is not bound to the selection of USERDEFINED within the PredefinedType enumaration. | X |
| 6 | LongName | IfcLabel | ? | Long name for the context as used for reference purposes. | X |
| 7 | Phase | IfcLabel | ? | Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements. | X |
| 8 | RepresentationContexts | IfcRepresentationContext | ? S[1:?] |
Context of the representations used within the context. When the context is a project and it includes shape representations for its components, one or several geometric representation contexts need to be included that define e.g. the world coordinate system, the coordinate space dimensions, and/or the precision factor.
IFC4 CHANGE The attribute has been changed to be optional. Change made with upward compatibility for file based exchange. | X |
| 9 | UnitsInContext | IfcUnitAssignment | ? |
Units globally assigned to measure types used within the context.
IFC4 CHANGE The attribute has been changed to be optional. Change made with upward compatibility for file based exchange. | X |
| IsDefinedBy | IfcRelDefinesByProperties @RelatedObjects | S[0:?] | Set of relationships to property set definitions attached to this context. Those statically or dynamically defined properties contain alphanumeric information content that further defines the context.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDeclares @RelatingContext | S[0:?] | Reference to the IfcRelDeclares relationship that assigns the uppermost entities of includes hierarchies to this context instance.
NOTE The spatial hiearchy is assigned to IfcProject using the IfcRelAggregates relationship. This is a single exception due to compatibility reasons with earlier releases. | X |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | Assignment of a globally unique identifier within the entire software world. | 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 |
| 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 |
| 4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @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 | |
| Nests | IfcRelNests @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).
IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition. | X | |
| IsNestedBy | IfcRelNests @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).
IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition. | X | |
| HasContext | IfcRelDeclares @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.
IFC4 CHANGE The inverse attribute datatype has been added. | X | |
| IsDecomposedBy | IfcRelAggregates @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).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| Decomposes | IfcRelAggregates @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).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| HasAssociations | IfcRelAssociates @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 | |
| IfcContext | |||||
| 5 | ObjectType | IfcLabel | ? |
The object type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes.
NOTE Subtypes of IfcContext do not introduce a PredefinedType attribute, therefore the usage of ObjectType is not bound to the selection of USERDEFINED within the PredefinedType enumaration. | X |
| 6 | LongName | IfcLabel | ? | Long name for the context as used for reference purposes. | X |
| 7 | Phase | IfcLabel | ? | Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements. | X |
| 8 | RepresentationContexts | IfcRepresentationContext | ? S[1:?] |
Context of the representations used within the context. When the context is a project and it includes shape representations for its components, one or several geometric representation contexts need to be included that define e.g. the world coordinate system, the coordinate space dimensions, and/or the precision factor.
IFC4 CHANGE The attribute has been changed to be optional. Change made with upward compatibility for file based exchange. | X |
| 9 | UnitsInContext | IfcUnitAssignment | ? |
Units globally assigned to measure types used within the context.
IFC4 CHANGE The attribute has been changed to be optional. Change made with upward compatibility for file based exchange. | X |
| IsDefinedBy | IfcRelDefinesByProperties @RelatedObjects | S[0:?] | Set of relationships to property set definitions attached to this context. Those statically or dynamically defined properties contain alphanumeric information content that further defines the context.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDeclares @RelatingContext | S[0:?] | Reference to the IfcRelDeclares relationship that assigns the uppermost entities of includes hierarchies to this context instance.
NOTE The spatial hiearchy is assigned to IfcProject using the IfcRelAggregates relationship. This is a single exception due to compatibility reasons with earlier releases. | X | |
| # | Concept | Template | Model View |
|---|---|---|---|
| IfcRoot | |||
| Identity | Software Identity | General Usage | |
| Revision Control | Revision Control | General Usage | |
| IfcObjectDefinition | |||
| Classification Association | Classification Association | General Usage | |
<xs:element name="IfcContext" type="ifc:IfcContext" abstract="true" substitutionGroup="ifc:IfcObjectDefinition" nillable="true"/>
<xs:complexType name="IfcContext" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcObjectDefinition">
<xs:sequence>
<xs:element name="RepresentationContexts" nillable="true" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcRepresentationContext" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcRepresentationContext"/>
<xs:attribute ref="ifc:cType" fixed="set"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
<xs:element name="UnitsInContext" type="ifc:IfcUnitAssignment" nillable="true" minOccurs="0"/>
<xs:element name="IsDefinedBy" nillable="true" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcRelDefinesByProperties" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcRelDefinesByProperties"/>
<xs:attribute ref="ifc:cType" fixed="set"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
<xs:element name="Declares" nillable="true" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element ref="ifc:IfcRelDeclares" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute ref="ifc:itemType" fixed="ifc:IfcRelDeclares"/>
<xs:attribute ref="ifc:cType" fixed="set"/>
<xs:attribute ref="ifc:arraySize" use="optional"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attribute name="ObjectType" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="LongName" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="Phase" type="ifc:IfcLabel" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcContext
ABSTRACT SUPERTYPE OF(ONEOF(IfcProject, IfcProjectLibrary))
SUBTYPE OF (IfcObjectDefinition);
ObjectType : OPTIONAL IfcLabel;
LongName : OPTIONAL IfcLabel;
Phase : OPTIONAL IfcLabel;
RepresentationContexts : OPTIONAL SET [1:?] OF IfcRepresentationContext;
UnitsInContext : OPTIONAL IfcUnitAssignment;
INVERSE
IsDefinedBy : SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects;
Declares : SET [0:?] OF IfcRelDeclares FOR RelatingContext;
END_ENTITY;
References: IfcRelDeclares
EXPRESS-G diagram
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