IFC 4.3.x development

8.18.3.12 IfcShapeAspect

Change log

IFC4

modificationsattributes PartOfProductDefinitionShape definition Changed from IfcProductDefinitionShape to IfcProductRepresentationSelect
modificationsattributes PartOfProductDefinitionShape is_optionalChanged from False to True
modificationsattributes ProductDefinitional definition Changed from logical to IfcLogical

IFC4X1

additionsinversesHasExternalReferences

8.18.3.12.1 Semantic definitions at the entity

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.

NOTE  The IfcShapeAspect together with the IfcMaterialConstituent can be used to associate distict material information to parts of the product shape representation.

Figure 1 indicates the association of material characteristics to shape aspects.

"shape"

NOTE  Definition from ISO 10303-41:
A shape aspect is an identifiable element of the shape of an object.

NOTE  Entity adapted from shape_aspect defined in ISO 10303-42.

HISTORY  New entity in IFC2.0

IFC4 CHANGE  Attribute PartOfProductDefinitionShape declared OPTIONAL and extended to type IfcProductRepresentationSelect with upward compatibility for file based exchange.

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.

8.18.3.12.1 Attributes

#Attribute Type Description
IfcShapeAspect
1ShapeRepresentationsLIST [1:?] OF IfcShapeModelList of ~~shape~~ representations. Each member defines a valid representation of a particular type within a particular representation context as being an aspect (or part) of a product definition.

> IFC2x3 CHANGE  The data type has been changed from IfcShapeRepresentation to IfcShapeModel with upward compatibility
2Name OPTIONAL IfcLabel The word or group of words by which the shape aspect is known. It is a tag to indicate the particular semantic of a component within the product definition shape, used to provide meaning. Example: use the tag "Glazing" to define which component of a window shape defines the glazing area.
3Description OPTIONAL IfcText The word or group of words that characterize the shape aspect. It can be used to add additional meaning to the name of the aspect.
4ProductDefinitional IfcLogical

8.18.3.12.2 Entity inheritance

dot_inheritance IfcShapeAspect IfcShapeAspect

8.18.3.12.3 Formal representations

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;