Archicad Doors and Windows with IfcOpeningElement

[Sefa Yakut]

Hi,

I am experiencing an issue during IFC export regarding the automatically generated 'IfcOpeningElement' entities created by doors and windows.

When validating our IFC models against strict IDS (Information Delivery Specification) requirements, these automatically generated opening elements fail the checks. The IDS requires a value for both the 'PredefinedType' and 'Name' attributes.

Even though I have set up explicit Data Mapping rules in the IFC Translator to assign a fallback 'Name' and specific parameters to 'IfcOpeningElement' (or IfcFeatureElementSubtraction), Archicad ignores these rules for the sub-elements generated by door/window wall cutouts. They are exported with PredefinedType as 'None' (or empty) and their 'Name' attributes are either left empty or cannot be overridden properly, resulting in validation failures in Solibri / BIMcollab.

If I use the Model Filter to exclude 'IfcOpeningElement', Archicad completely closes the wall voids, which ruins the geometry.

Is there a hidden way, a workaround, or a planned hotfix to allow users to force Data Mapping rules onto these automatically generated opening sub-elements without breaking the host wall geometry?

Thank you.

Operating system used: Windows

[Laszlo Nagy]

I don't know a workaround or fix in Archicad, but you can take the exported IFC file, and potentially fix these missing values there.

There are solutions that let you read, modify, and save IFC files.

One such solution is IfcOpenShell, which is a Python library.

Another is Bonsai, the BIM Add-On developed on top of Blender, which is also based on IfcOpenShell.

IfcOpenShell just runs from your command prompt, while Bonsai will be able to load and display your full IFC file, so visually that is easier.

In either of these, you can modify the IFC Properties of IFC elements in the IFC file.

So, I think you should be able to fill out those missing IFC Property values of the IfcOpeningElement entities and save the result. Then you can run the IDS check on them to make sure they pass.

I had a recent test where I was saving the individual skins of Composite Walls in the IFC, and as it turns out the exact sizes (Length, Height) of the skins were not calculated correctly in Archicad, so when I mapped their values to IFC Properties, they did not contain the accurate values. So, I used IfcOpenShell to check the actual length, width, and height values of the individual skins as stored in the IFC file (they were saved as BREPs so I knew the geometries were correct), and based on those results, I modified the corresponding IFC Properties within the file. Then, the IFC Properties did contain the accurate dimensions of each individual composite skin. Actually, Claude Desktop guided me through the whole process and I achieved the desired result perfectly.

This can be turned into a workflow. Obviously, it is an extra step after the IFCs are exported from Archicad, but the result is a correct IFC file.