IFC 4.3.0.1 (IFC4X3_TC1)

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.

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.

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;

8.8.3.21.6 References

8.8.3.21.7 Changelog

8.8.3.21.7.1 IFC4

  • where rule, ConsistentDim
  • where rule, WR21