5.1.3.3 IfcContext

RV ⓘ

AbV ⓘ

ABSTRACT This definition may not be instantiated

5.1.3.3.1 Semantic 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.

5.1.3.3.2 Entity inheritance

5.1.3.3.3 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, NOTE Only the last modification is stored - either as addition, deletion or modification. IFC4-CHANGE 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). IFC4-CHANGE 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). IFC4-CHANGE 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. IFC4-CHANGE 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). IFC4-CHANGE 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). IFC4-CHANGE 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
IfcContext (7)
5	ObjectType	OPTIONAL 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 enumeration.
6	LongName	OPTIONAL IfcLabel	Long name for the context as used for reference purposes.
7	Phase	OPTIONAL IfcLabel	Current project phase, or life-cycle phase of this project. Applicable values have to be agreed upon by view definitions or implementer agreements.
8	RepresentationContexts	OPTIONAL SET [1:?] OF IfcRepresentationContext	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.
9	UnitsInContext	OPTIONAL 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.
	IsDefinedBy	SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects	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.
	Declares	SET [0:?] OF IfcRelDeclares FOR RelatingContext	Reference to the IfcRelDeclares relationship that assigns the uppermost entities of included hierarchies to this context instance. NOTE The spatial hierarchy is assigned to IfcProject using the IfcRelAggregates relationship. This is a single exception due to compatibility reasons with earlier releases.

Table 5.1.3.3.A

5.1.3.3.4 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.
Document Association	General	No description available.
Library Association	General	No description available.
Material Association	General	No description available.
Material Single	General	No description available.
Nesting	General	No description available.
Click to show 11 hidden inherited concepts
IfcContext (7)
Project Classification Information	General	No description available.
Project Context	General	No description available.
Project Document Information	General	No description available.
Project Library Information	General	No description available.
Project Representation Context 3D	General	No description available.
Project Template Definitions	General	No description available.
Project Type Definitions	General	No description available.

Table 5.1.3.3.B

5.1.3.3.5 Formal representation

 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;