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 within the wall is defined by the pattern IfcWall - IfcRelVoidsElement - IfcOpeningElement.

5.4.3.62.2 Entity inheritance

1. • IfcRoot
2. • IfcRelationship
   • IfcObjectDefinition
   • IfcPropertyDefinition
3. • IfcRelDecomposes
   • IfcRelAssigns
   • IfcRelAssociates
   • IfcRelConnects
   • IfcRelDeclares
   • IfcRelDefines
4. • IfcRelVoidsElement
   • IfcRelAdheresToElement
   • IfcRelAggregates
   • IfcRelNests
   • IfcRelProjectsElement

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,
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 the element in which a void is created by the associated feature subtraction element.
6	RelatedOpeningElement	IfcFeatureElementSubtraction	Reference to the feature subtraction element which defines a void in the associated element.

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.
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5.4.3.62.5 Examples

• 

  Slab Openings

5.4.3.62.6 Formal representation

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

5.4.3.62.7 References

• IfcElement
• IfcFeatureElementSubtraction
• IfcRelDecomposes