IfcGeometricSet

Semantic definitions at the entity

Entity 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).

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

NOTE Entity adapted from geometric_set defined in ISO 10303-42.

HISTORY New entity in IFC2x.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
1	Elements	IfcGeometricSetSelect	S[1:?]	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.	X
	Dim :=Elements[1].Dim	IfcDimensionCount		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.	X

Formal Propositions

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

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	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.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	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.	X
IfcGeometricRepresentationItem
IfcGeometricSet
1	Elements	IfcGeometricSetSelect	S[1:?]	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.	X
	Dim :=Elements[1].Dim	IfcDimensionCount		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.	X

Formal representations

XML Specification

 <xs:element name="IfcGeometricSet" type="ifc:IfcGeometricSet" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>

 <xs:complexType name="IfcGeometricSet">

  <xs:complexContent>

   <xs:extension base="ifc:IfcGeometricRepresentationItem">

    <xs:sequence>

     <xs:element name="Elements">

      <xs:complexType>

       <xs:group ref="ifc:IfcGeometricSetSelect" maxOccurs="unbounded"/>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcGeometricSetSelect"/>

       <xs:attribute ref="ifc:cType" fixed="set"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcGeometricSet

 SUPERTYPE OF(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;

 EXPRESS-G diagram

	Geometrische Gruppe
	Geometric Set