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IfcShapeAspect

Definition from ISO/CD 10303-42:1992: The shape aspect is an identifiable element of the shape of a product.

Definition from IAI: The 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 representing a distinctive part of a product that can be explicitly addressed.

NOTE: The definition of this class relates to the STEP entity shape_aspect. Please refer to ISO/IS 10303-41:1994 for the final definition of the formal standard.
ISSUE: See issue and change log for changes made in IFC Release 1.5 and IFC 2x.
HISTORY: New Entity in IFC Release 2.0

EXPRESS specification:

ENTITY IfcShapeAspect;
ShapeRepresentations  :  LIST [1:?] OF IfcShapeRepresentation;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ProductDefinitional  :  LOGICAL;
PartOfProductDefinitionShape  :  IfcProductDefinitionShape;
END_ENTITY;

Attribute definitions:

ShapeRepresentations  :  Contained list of shape representations. Each member defining a valid shape representation of a particular type (i.e. bounding box, attribute driven, explicit) within a particular representation context.
Name  :  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.
Description  :  The word or group of words that characterize the shape_aspect. It can be used to add additional meaning the the name of the aspect.
ProductDefinitional  :  An indication that the shape aspect is on the physical boundary of the product_definition_shape. If the value of this attribute is TRUE, it shall be asserted that the shape_aspect being identified is on such a boundary. If the value is FALSE, it shall be asserted that the shape_aspect being identified is not on such a boundary. If the value is UNKNOWN, it shall be asserted that it is not known whether or not the shape_aspect being identified is on such a boundary. EXAMPLE: Would be FALSE for a center line, identified as shape aspect, would be TRUE for a cantilever.
PartOfProductDefinitionShape  :  Reference to the product definition shape of which this class is an aspect.

References (2):

Name Type Referred through Express-G
IfcProductDefinitionShape Entity
Attribute 'HasShapeAspects'
Diagram 2
IfcShapeRepresentation Entity
Attribute 'OfShapeAspect'
Diagram 2

Inheritance graph

ENTITY IfcShapeAspect;
ENTITY IfcShapeAspect;
ShapeRepresentations  :  LIST [1:?] OF IfcShapeRepresentation;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ProductDefinitional  :  LOGICAL;
PartOfProductDefinitionShape  :  IfcProductDefinitionShape;
END_ENTITY;