IfcShapeModel

BACnet MVD

#### IfcShapeModel

Natural language names

| Form - Modell
| Shape Model
| Modèle de forme

##### Semantic definitions at the entity

Entity 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 conectivity 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).

> HISTORY New entity in IFC2x3.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
| OfShapeAspect | IfcShapeAspect @ShapeRepresentations | S[0:1] | Reference to the shape aspect, for which it is the shape representation. |  | X

Formal Propositions

Rule | Description
--- | ---
WR11 | The IfcShapeModel shall be used by an IfcProductRepresentation, by an IfcRepresentationMap or by an IfcShapeAspect.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRepresentation
1 | ContextOfItems | IfcRepresentationContext |  | Definition of the representation context for which the different subtypes of representation are valid. | X | X
2 | RepresentationIdentifier | IfcLabel | ? | The optional identifier of the representation as used within a project. | X | X

3

RepresentationType

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.

X

X

4 | Items | IfcRepresentationItem | S[1:?] | Set of geometric representation items that are defined for this representation. | X | X

RepresentationMap

IfcRepresentationMap
@MappedRepresentation

S[0:1]

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

X

LayerAssignments

IfcPresentationLayerAssignment
@AssignedItems

S[0:?]

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

X

OfProductRepresentation

IfcProductRepresentation
@Representations

S[0:?]

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.

X

IfcShapeModel
| OfShapeAspect | IfcShapeAspect @ShapeRepresentations | S[0:1] | Reference to the shape aspect, for which it is the shape representation. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcShapeModel" type="ifc:IfcShapeModel" abstract="true" substitutionGroup="ifc:IfcRepresentation" nillable="true"/>
<xs:complexType name="IfcShapeModel" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:IfcRepresentation"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`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;

EXPRESS-G diagram

`

References: IfcShapeAspect

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