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 A indicates the association of material characteristics to shape aspects.
{ .extDef}
{ .change-ifc2x4}
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;
