#### IfcGeometricSet

Natural language names

##### Semantic definitions at the entity

Entity definition

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

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.

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
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 | [1:1] | 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
--- | ---
WR21 | All elements within a geometric set shall have the same dimensionality.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRepresentationItem
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 | [1:1] | 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

XSD 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
WR21 : SIZEOF(QUERY(Temp <* Elements | Temp.Dim <> Elements[1].Dim)) = 0;
END_ENTITY;

EXPRESS-G diagram

`

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