8.18.3.13 IfcShapeModel

ABSTRACT This definition may not be instantiated

8.18.3.13.1 Semantic definition

IfcShapeModel represents the concept of a particular geometric and/or topological representation of a product's shape or a product component's shape within a representation context. This representation context has to be a geometric representation context (with the exception of topology representations without associated geometry). The two subtypes are IfcShapeRepresentation to cover geometric models that represent a shape, and IfcTopologyRepresentation to cover the connectivity of a product or product component. The topology may or may not have geometry associated.

The IfcShapeModel can be a shape representation (geometric and/or topologogical) of a product (via IfcProductDefinitionShape), or a shape representation (geometric and/or topologogical) of a component of a product shape (via IfcShapeAspect).

8.18.3.13.2 Entity inheritance

8.18.3.13.3 Attributes

#	Attribute	Type	Description
IfcRepresentation (7)
1	ContextOfItems	IfcRepresentationContext	Definition of the representation context for which the different subtypes of representation are valid.
2	RepresentationIdentifier	OPTIONAL IfcLabel	The optional identifier of the representation as used within a project.
3	RepresentationType	OPTIONAL IfcLabel	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.
4	Items	SET [1:?] OF IfcRepresentationItem	Set of geometric representation items that are defined for this representation.
	RepresentationMap	SET [0:1] OF IfcRepresentationMap FOR MappedRepresentation	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. IFC2x3-CHANGE The inverse attribute LayerAssignments has been added
	LayerAssignments	SET [0:?] OF IfcPresentationLayerAssignment FOR AssignedItems	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. IFC2x3-CHANGE The inverse attribute LayerAssignments has been added
	OfProductRepresentation	SET [0:?] OF IfcProductRepresentation FOR Representations	Reference to the product representations to which this individual representation applies. In most cases it is the reference to one or many product shapes, to which this shape representation is applicable. IFC4-CHANGE Inverse relationship cardinality relaxed to be 0:N.
Click to show 7 hidden inherited attributes Click to hide 7 inherited attributes
IfcShapeModel (1)
	OfShapeAspect	SET [0:1] OF IfcShapeAspect FOR ShapeRepresentations	Reference to the shape aspect, for which it is the shape representation.

Table 8.18.3.13.A

8.18.3.13.4 Formal propositions

Name	Description
WR11	The IfcShapeModel shall be used by an IfcProductRepresentation, by an IfcRepresentationMap or by an IfcShapeAspect.
`(SIZEOF(SELF\IfcRepresentation.OfProductRepresentation) = 1) XOR (SIZEOF(SELF\IfcRepresentation.RepresentationMap) = 1) XOR (SIZEOF(OfShapeAspect) = 1)`

Table 8.18.3.13.B

8.18.3.13.5 Formal representation

ENTITY IfcShapeModel
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcShapeRepresentation
	,IfcTopologyRepresentation))
 SUBTYPE OF (IfcRepresentation);
 INVERSE
	OfShapeAspect : SET [0:1] OF IfcShapeAspect FOR ShapeRepresentations;
 WHERE
	WR11 : (SIZEOF(SELF\IfcRepresentation.OfProductRepresentation) = 1) XOR 
(SIZEOF(SELF\IfcRepresentation.RepresentationMap) = 1) XOR
(SIZEOF(OfShapeAspect) = 1);
END_ENTITY;