8.8.3.21 IfcGeometricSet

8.8.3.21.1 Semantic definition

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

8.8.3.21.2 Entity inheritance

8.8.3.21.3 Attributes

#	Attribute	Type	Description
IfcRepresentationItem (2)
	LayerAssignment	SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems	Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. IFC2x3-CHANGE The inverse attribute LayerAssignments has been added. IFC4-CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
	StyledByItem	SET [0:1] OF IfcStyledItem FOR Item	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. IFC2x3-CHANGE The inverse attribute StyledByItem has been added.
Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes
IfcGeometricSet (2)
1	Elements	SET [1:?] OF IfcGeometricSetSelect	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	IfcDimensionCount	This attribute is formally derived. `Elements[1].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.

Table 8.8.3.21.A

8.8.3.21.4 Formal propositions

Name	Description
ConsistentDim	All elements within a geometric set shall have the same dimensionality.
`SIZEOF(QUERY(Temp <* Elements \| Temp.Dim <> Elements[1].Dim)) = 0`

Table 8.8.3.21.B

8.8.3.21.5 Formal representation

ENTITY IfcGeometricSet
 SUPERTYPE OF (ONEOF
	(IfcGeometricCurveSet))
 SUBTYPE OF (IfcGeometricRepresentationItem);
	Elements : SET [1:?] OF IfcGeometricSetSelect;
 DERIVE
	 Dim : IfcDimensionCount := Elements[1].Dim;
 WHERE
	ConsistentDim : SIZEOF(QUERY(Temp <* Elements |
  Temp.Dim <> Elements[1].Dim))
= 0;
END_ENTITY;