IfcContext

Natural language names
deKontextinformation
enContext
frContexte
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcContextADDED
Semantic definitions at the entity
Entity definition

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 definitions
#AttributeTypeCardinalityDescription B
5ObjectTypeIfcLabel[0:1] 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
6LongNameIfcLabel[0:1] Long name for the context as used for reference purposes.X
7PhaseIfcLabel[0:1] Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements. X
8RepresentationContextsIfcRepresentationContextS[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. X
9UnitsInContextIfcUnitAssignment[0:1] Units globally assigned to measure types used within the context. X
IsDefinedByIfcRelDefinesByProperties
@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.
DeclaresIfcRelDeclares
@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
Inherited definitions from supertypes
Entity inheritance IfcProject IfcProjectLibrary IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionB
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).
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.
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
IfcContext
5ObjectTypeIfcLabel[0:1] 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
6LongNameIfcLabel[0:1] Long name for the context as used for reference purposes.X
7PhaseIfcLabel[0:1] Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements. X
8RepresentationContextsIfcRepresentationContextS[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. X
9UnitsInContextIfcUnitAssignment[0:1] Units globally assigned to measure types used within the context. X
IsDefinedByIfcRelDefinesByProperties
@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.
DeclaresIfcRelDeclares
@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
Definitions applying to Bridge View

Concept inheritance

#ConceptModel View
IfcRoot
Software IdentityBridge View
User IdentityBridge View
Object OwnershipBridge View
Formal representations
XSD Specification
 <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="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>
EXPRESS Specification
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 OF IfcRelDeclares FOR RelatingContext;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Link to this page  Link to this page