# Can the concept of Reference Geometry be applied to IfcVoidingFeature in the same way as IfcOpeningElement?

**URL:** <https://forums.buildingsmart.org/t/can-the-concept-of-reference-geometry-be-applied-to-ifcvoidingfeature-in-the-same-way-as-ifcopeningelement/5177>\
**Category:** IFC4\
**Tags:** ifc\
**Created:** [February 22, 2024, 5:29pm UTC](https://forums.buildingsmart.org/t/can-the-concept-of-reference-geometry-be-applied-to-ifcvoidingfeature-in-the-same-way-as-ifcopeningelement/5177 "2024-02-22T17:29:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![iwtk](https://avatars.discourse-cdn.com/v4/letter/i/e19adc/32.png) [@iwtk](https://forums.buildingsmart.org/u/iwtk)\
**Post date:** [February 22, 2024, 5:29pm UTC](https://forums.buildingsmart.org/t/can-the-concept-of-reference-geometry-be-applied-to-ifcvoidingfeature-in-the-same-way-as-ifcopeningelement/5177/1 "2024-02-22T17:29:45Z")

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Hi!  
Can the concept of `Reference Geometry` be applied to` IfcVoidingFeature` in the same way as `IfcOpeningElement`?

[https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2\_TC1/HTML/link/ifcvoidingfeature.htm](https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/link/ifcvoidingfeature.htm)

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**Author:** ![yauron](https://avatars.discourse-cdn.com/v4/letter/y/7ba0ec/32.png) [@yauron](https://forums.buildingsmart.org/u/yauron)\
**Post date:** [February 24, 2024, 8:11am UTC](https://forums.buildingsmart.org/t/can-the-concept-of-reference-geometry-be-applied-to-ifcvoidingfeature-in-the-same-way-as-ifcopeningelement/5177/2 "2024-02-24T08:11:57Z")

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I’m not the best person to answers, but, as it is written, Voiding means empty space. The question is “how you get this void ?” If you want to explain it, you need this object.

OpeningElement, as it is written, have a means. It will dock an opening entity, like Doors or Windows. Like every IFC mechanism, links between entities needs IfcRel objects. One set a void into a wall, another, set an opening into the wall.  
So the rel question is “must i create mutual sub objects (location,…) for the same whole ?” And i don’t know it.