5.4.3.62 IfcRelVoidsElement

5.4.3.62.1 Semantic definition

IfcRelVoidsElement is an objectified relationship between a 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.

As shown in Figure 5.4.3.62.A, the insertion of a void into a wall is represented by the relationship IfcRelVoidsElement. The opening is created within the wall by IfcWall o-- IfcRelVoidsElement --o IfcOpeningElement.

relationships for voiding — Figure 5.4.3.62.A — Relationship for element voiding

5.4.3.62.2 Entity inheritance

- IfcRoot

5.4.3.62.3 Attributes

#	Attribute	Type	Description
IfcRoot (4)
1	GlobalId	IfcGloballyUniqueId	Assignment of a globally unique identifier within the entire software world.
2	OwnerHistory	OPTIONAL IfcOwnerHistory	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 - either as addition, deletion or modification. IFC4-CHANGE The attribute has been changed to be OPTIONAL.
3	Name	OPTIONAL IfcLabel	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.
4	Description	OPTIONAL IfcText	Optional description, provided for exchanging informative comments.
Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes
IfcRelVoidsElement (2)
5	RelatingBuildingElement	IfcElement	Reference to element in which a void is created by associated feature subtraction element. IFC2x-CHANGE The data type has been changed from IfcBuildingElement to IfcElement with upward compatibility for file based exchange.
6	RelatedOpeningElement	IfcFeatureElementSubtraction	Reference to the feature subtraction element which defines a void in the associated element. IFC2x-CHANGE The data type has been changed from IfcOpeningElement to IfcFeatureElementSubtraction with upward compatibility for file based exchange.

Table 5.4.3.62.B

5.4.3.62.4 Concept usage

Concept	Usage	Description
IfcRoot (2)
Revision Control	General	Ownership, history, and merge state is captured using IfcOwnerHistory.
Software Identity	General	IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Click to show 2 hidden inherited concepts Click to hide 2 inherited concepts

Table 5.4.3.62.C

5.4.3.62.5 Formal representation

ENTITY IfcRelVoidsElement
 SUBTYPE OF (IfcRelDecomposes);
	RelatingBuildingElement : IfcElement;
	RelatedOpeningElement : IfcFeatureElementSubtraction;
END_ENTITY;