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IfcRepresentation

Definition from ISO/CD 10303-43:1992: A representation is one or more representation items that are related in a specified representation context as the representation of some concept.

Definition from IAI: The IfcRepresentation defines the general concept of representing product properties.

NOTE  The definition of this entity relates to the STEP entity representation. Please refer to ISO/IS 10303-43:1994 for the final definition of the formal standard.
HISTORY  New entity in IFC Release 2.0

IFC2x Edition 3 NOTE  Users should not instantiate the entity IfcRepresentation from IFC2x Edition 3 onwards. It will be changed into an ABSTRACT supertype in future releases of IFC.
IFC2x Edition 3 CHANGE  The inverse attributes LayerAssignments and RepresentationMap have been added with upward compatibility.

EXPRESS specification:

ENTITY IfcRepresentation
SUPERTYPE OF (ONEOF(IfcStyleModel, IfcShapeModel));
ContextOfItems  :  IfcRepresentationContext;
RepresentationIdentifier  :  OPTIONAL IfcLabel;
RepresentationType  :  OPTIONAL IfcLabel;
Items  :  SET [1:?] OF IfcRepresentationItem;
INVERSE
RepresentationMap  :  SET [0:1] OF IfcRepresentationMap FOR MappedRepresentation;
LayerAssignments  :  SET OF IfcPresentationLayerAssignment FOR Assigneditems;
OfProductRepresentation  :  SET [0:1] OF IfcProductRepresentation FOR Representations;
END_ENTITY;

Attribute definitions:

ContextOfItems  :  Definition of the representation context for which the different subtypes of representation are valid.
RepresentationIdentifier  :  The optional identifier of the representation as used within a project.
RepresentationType  :  The description of the type of a representation context. The representation type defines the type of geometry or topology used for representing the product representation. More information is given at the subtypes IfcShapeRepresentation and IfcTopologyRepresentation.
The supported values for context type are to be specified by implementers agreements.
Items  :  Set of geometric representation items that are defined for this representation.
RepresentationMap  :  Use of the representation within an IfcRepresentationMap. If used, this IfcRepresentation may be assigned to many representations as one of its Items using an IfcMappedItem. Using IfcRepresentationMap is the way to share one representation (often of type IfcShapeRepresentation) by many products.
IFC2x Edition 3 CHANGE  The inverse attribute LayerAssignments has been added.
LayerAssignments  :  Assignment of the whole representation to a single or multiple layer(s). The LayerAssigments can be overridden by LayerAssigments of the IfcRepresentationItem's within the list of Items.
NOTE  Implementation agreements can restrict the maximum number of layer assignments to 1.
IFC2x Edition 3 CHANGE  The inverse attribute LayerAssignments has been added.
OfProductRepresentation  :  Reference to the product shape, for which it is the shape representation.

Inheritance graph

ENTITY IfcRepresentation;
ENTITY IfcRepresentation;
ContextOfItems  :  IfcRepresentationContext;
RepresentationIdentifier  :  OPTIONAL IfcLabel;
RepresentationType  :  OPTIONAL IfcLabel;
Items  :  SET [1:?] OF IfcRepresentationItem;
INVERSE
RepresentationMap  :  SET [0:1] OF IfcRepresentationMap FOR MappedRepresentation;
LayerAssignments  :  SET OF IfcPresentationLayerAssignment FOR Assigneditems;
OfProductRepresentation  :  SET [0:1] OF IfcProductRepresentation FOR Representations;
END_ENTITY;