topic Expression-based properties not exporting with IFC translator from hotlinked modules. in Project data & BIM

Expression-based properties not exporting with IFC translator from hotlinked modules.

Ben D — Thu, 02 Jul 2026 05:47:47 GMT

Hi, I'm using a customised IFC4 translator, which uses some custom property mappings to map custom expression based properties to IFC fields.

The project is a multistorey building that is using the iceberg method to model a typical level. the typical level is modeled once then hotlinked up into the building multiple times.

When we then do an IFC export, the expression based properties for the hotlinked elements do not seem to populate. They work perfectly for the non-hotlinked elements.

Has anyone else come across this or know of a workaround? Can anyone from Graphisoft confirm this is an issue?

Thanks

Ben

Operating system used: Mac Apple Silicon Sequoia 15.7.5

Re: Expression-based properties not exporting with IFC translator from hotlinked modules.

Ben D — Thu, 02 Jul 2026 07:34:10 GMT

Actually, this turns out not to be the problem - you can't see the calculate button in the property when it's a hotlink, but it does actually work for the IFC export.

The issue seems to be to do specifically with elements which have separate sub-elements. eg curtain walls, which have sub-elements for for frames and panels, and railings, which have sub elements for posts, rails, balusters, etc. these sub-elements end up missing the calculated fields, even when the properties are set to be available to elements with All classifications, even though their parent element (the Curatin Wall or Railing) is correctly showing the calculated property.

Betreff: Expression-based properties not exporting with IFC translator from hotlinked modules.

mgg — Fri, 03 Jul 2026 08:45:19 GMT

Have you already tried setting the IFC translator you're using as preview?

Then you should be able to see the IFC properties of the element at the very bottom of the element properties.

Maybe that will help you solve the actual problem.