# 8.18.3.15 IfcShapeAspect

AbRV ⓘ
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## 8.18.3.15.1 Semantic definition

IfcShapeAspect allows for grouping of shape representation items that represent aspects (or components) of the shape of a product. Thereby shape representations of components of the product shape represent a distinctive part to a product that can be explicitly addressed.

The IfcShapeAspect's may have distinct material information or other distict characteristics that differs from other parts of the product shape representation.

Figure 8.18.3.15.A indicates the association of material characteristics to shape aspects.

Informal Propositions:

1. If ShapeRepresentations points to shape representations that are part of an IfcProductDefinitionShape, PartOfProductDefinitionShape must refer to this instance of IfcProductDefinitionShape.
2. If ShapeRepresentations points to shape representations that are part of an IfcRepresentationMap, PartOfProductDefinitionShape must refer to this instance of IfcRepresentationMap.

## 8.18.3.15.4 Formal representation

ENTITY IfcShapeAspect;
ShapeRepresentations : LIST [1:?] OF IfcShapeModel;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ProductDefinitional : IfcLogical;
PartOfProductDefinitionShape : OPTIONAL IfcProductRepresentationSelect;
INVERSE
HasExternalReferences : SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
END_ENTITY;