Circular openings in slanted slabs export as hexagons in IFC4 RV Arch

[andydandy74]

Openings with curved edges in slanted slabs are grossly simplified in IFC 4 RV Arch. (IFC2x3 CV 2.0 is fine):

• Revit version: 2023.1.1
• IFC version: 23.2.3

[AngelVelezSosa]

A hexagon does seem on the simpler side ... we will look into why the tessellation is so coarse. @parrela, please file this also.

[andydandy74]

Here's a model. Happens with floor slabs and foundation slabs. Roofs and ceilings work fine.
115_IFC_CircularSlabOpeningsExportAsHexagons.zip

[YasmineDenruyter]

Not sure if this is completely relevant, so if not just ignore this, but we also tested whether the opening is exported as an IfcOpening and this isn't the case for every kind of 'void' or 'opening' you make in Revit. I have some pictures below showing depending on which type of 'opening' you create (i.e. vertical opening/edit footprint/void family/...) whether it gets exported to an IfcOpening or not (all test were done with Revit 2022.1.3 and exporter 22.5.0.0.):
v = checked
'-' = not applicable
x = no IfcOpening
! = solved in Revit 2023

The purple ones are the IfcOpenings

[andydandy74]

@YasmineArcadis Awesome work! We've had an internal issue for this, too, that I meant to post here, but hadn't finished my testing yet. Our preliminary tests also showed that no IfcOpening entities were created for openings in beams, columns, structural columns or foundations (not sure about foundation slabs).

I would suggest you create a separate issue for this so it gets the attention it deserves.

What also bugs me is the inconsistent naming of IfcOpening profile names (but that would be yet another issue).

[AngelVelezSosa]

@YasmineArcadis do you have that Revit file?

[YasmineDenruyter]

BPL-000_MOD_Empty Template Openings.zip
This is the RVT file (2022)

[parrela]

OK, thank you @YasmineArcadis for that comprehensive document! In Dev-2024 I only see two cases where openings become hexagons: when the floor is edited. So I will file that to get looked at. I will also file an item for IfcOpening elements that should be created.

[JOuellette-Autodesk]

https://jira.autodesk.com/browse/REVIT-200695