8.18.3.15 IfcShapeAspect
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 distinct 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
- If ShapeRepresentations points to shape representations that are part of an IfcProductDefinitionShape, PartOfProductDefinitionShape must refer to this instance of IfcProductDefinitionShape.
- If ShapeRepresentations points to shape representations that are part of an IfcRepresentationMap, PartOfProductDefinitionShape must refer to this instance of IfcRepresentationMap.
8.18.3.15.2 Entity inheritance
8.18.3.15.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcShapeAspect (6) | |||
| 1 | ShapeRepresentations | LIST [1:?] OF IfcShapeModel |
List 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. |
| 2 | Name | 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. |
| 3 | Description | 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. |
| 4 | ProductDefinitional | IfcLogical |
An indication that the shape aspect is on the physical boundary of the product definition shape. * TRUE: the shape aspect represents geometry that sits on (or forms) the physical outer boundary of the product's definition shape. Example: the glazing panel face of a window, or the top surface of a slab — geometry that is part of what defines the product's extent in space. * FALSE: the shape aspect represents geometry that does not form the physical boundary. Example: a centre line (e.g., of a beam or pipe), it is a useful reference geometry derived from the product, but it does not coincide with the product's physical surface. UNKNOWN: it cannot be asserted either way. |
| 5 | PartOfProductDefinitionShape | OPTIONAL IfcProductRepresentationSelect |
Reference to the IfcProductDefinitionShape or the IfcRepresentationMap of which this shape is an aspect. |
| HasExternalReferences | SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects |
External references (e.g. classification) associated with the shape aspect. |
|
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;