#### IfcRelVoidsElement

Natural language names

##### Semantic definitions at the entity

Entity definition

Objectified relationship between an building element and one opening element that creates a void in the element. It is a one-to-one relationship. This relationship implies a Boolean operation of subtraction between the geometric bodies of the element and the opening.

Figure The insertion of a void into a wall is represented by the relationship IfcRelVoidsElement. The opening is created within the wall by IfcWall(StandardCase) o-- IfcRelVoidsElement --o IfcOpeningElement.

> HISTORY New entity in IFC Release 1.0

Attribute definitions

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
5 | RelatingBuildingElement | IfcElement | [1:1] | Reference to building element in which a void is created by associated opening feature subtraction element. | X
6 | RelatedOpeningElement | IfcFeatureElementSubtraction | [1:1] | Reference to the opening feature subtraction element which defines a void in the associated opening element. | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | A
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId | [1:1] | Assignment of a globally unique identifier within the entire software world. | X
2 | OwnerHistory | IfcOwnerHistory | [1:1] | Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE: only the last modification in stored. | X
3 | Name | IfcLabel | [0:1] | Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule. | X
4 | Description | IfcText | [0:1] | Optional description, provided for exchanging informative comments. | X
IfcRelationship
IfcRelConnects
IfcRelVoidsElement
5 | RelatingBuildingElement | IfcElement | [1:1] | Reference to building element in which a void is created by associated opening feature subtraction element. | X
6 | RelatedOpeningElement | IfcFeatureElementSubtraction | [1:1] | Reference to the opening feature subtraction element which defines a void in the associated opening element. | X

##### Formal representations

XSD Specification
`<xs:element name="IfcRelVoidsElement" type="ifc:IfcRelVoidsElement" substitutionGroup="ifc:IfcRelConnects" nillable="true"/>
<xs:complexType name="IfcRelVoidsElement">
<xs:complexContent>
<xs:extension base="ifc:IfcRelConnects">
<xs:sequence>
<xs:element name="RelatingBuildingElement" type="ifc:IfcElement" nillable="true"/>
<xs:element name="RelatedOpeningElement" type="ifc:IfcFeatureElementSubtraction" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcRelVoidsElement
SUBTYPE OF (IfcRelConnects);
RelatingBuildingElement : IfcElement;
RelatedOpeningElement : IfcFeatureElementSubtraction;
END_ENTITY;

EXPRESS-G diagram

`

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