IfcGeometricSet

IfcGeometricSet

Definition from ISO/CD 10303-42:1992: This entity is intended for the transfer of models when a topological structure is not available.

Definition from IAI: The IfcGeometricSet is used for the exchange of shape representations consisting of (2D or 3D) points, curves, and/or surfaces, which do not have a topological structure (such as connected face sets or shells) and are not solid models (such as swept solids, CSG or Brep)

NOTE: Corresponding STEP entity: geometric_set. The derived attribute Dim has been added at this level and was therefore demoted from the geometric_representation_item. Please refer to ISO/IS 10303-42:1994, p. 190 for the final definition of the formal standard.

HISTORY: New entity in IFC Release 2x.

EXPRESS specification:

ENTITY IfcGeometricSet

SUPERTYPE OF

(IfcGeometricCurveSet)

SUBTYPE OF (

IfcGeometricRepresentationItem);

Elements

SET [1:?] OF IfcGeometricSetSelect;

DERIVE

Dim

IfcDimensionCount := Elements[1].Dim;

WHERE

WR21

SIZEOF(QUERY(Temp <* Elements | Temp.Dim <> Elements[1].Dim)) = 0;

END_ENTITY;

Attribute definitions:

Elements	:	The geometric elements which make up the geometric set, these may be points, curves or surfaces; but are required to be of the same coordinate space dimensionality.
Dim	:	The space dimensionality of this class, it is identical to the first element in the set. A where rule ensures that all elements have the same dimensionality.

Formal Propositions:

WR21

All elements within a geometric set shall have the same dimensionality.

Inheritance graph

ENTITY IfcGeometricSet;

ENTITY IfcRepresentationItem;