Spotlight: Revit 2027 IFC 27.4, and a property set that is not Other
Autodesk posted IFC add-in 27.4.0.30 for Revit 2027. Extended properties leave Other, and Show Parts walls get a geometry fix.
Yesterday’s leftover standard was Guangdong’s drawing-to-model review. The unused IFC leftover is Autodesk’s IFC add-in 27.4.0.30 for Revit 2027. GitHub dated the tag 30 October 2026. The previous public 2027 build was 27.3.0.12 on 13 August.
That is not a new CDE. Firms already export IFC from Revit, then argue about why a fire rating sat in Other and why a parts wall moved. 27.4’s useful claim is narrower: extended properties get their own set, and those walls are supposed to stay put.
What the notes actually say
The 27.4.0.30 notes list one improvement. Extended properties now export into their own property set, named after the element that contains them, instead of into the Other property set. That is a naming and grouping change. It is not a new information standard.
The rest is defect work that BIM leads already trip over. Some mapped parameters were not writing into user-defined property sets. The IFC parameters dialog did not open when you edited family type parameters. A wall could shift when you exported with Show Parts. Wall geometry could be wrong on IFC2x3 and IFC4x3.
Revit 2027 Help already named IFC parameter mapping as a 2027 export job: map parameters to property sets in the export workflow. Autodesk’s support article still tells you to turn on Export user defined property sets and point at a UTF-8 mapping file if you want a controlled set. 27.4 does not replace that file. It is supposed to write the mappings you already made.
Do not read the Other change as “export every Revit parameter.” Autodesk still warns that Export Revit property sets dumps internal groups, inflates the file, and is for testing. Keep the issued exchange to the sets named in the BEP.
How it actually lands
The project README says this add-in is the .NET code Revit uses for Link IFC, IFC export and the export UI. The open-source build overrides the copy that ships with Revit. The 27.4 assets include IFC.for.Revit.2027.4.0.30.msi. Autodesk also says builds from 2023 onward can appear in the Autodesk Desktop App, depending on the user and the licence. Confirm which path the office actually installed before you tell a client the seat is on 27.4.
Support is the current annual version and the two before it. Older years do not get this patch. The code is LGPLv2. The steel-connections DLL that ships with it stays under Autodesk’s terms.
This is not ISO 19650. The add-in writes an IFC. The package that leaves the firm still has to be named, dated and approved in the CDE you already run.
What a BIM lead should do
If the office is already on Revit 2027 and issues IFC, this is worth a morning on a non-sensitive job. Install 27.4 from the GitHub release, or from the Desktop App if that is how you patch. Export the same model you issued last week. Then ask four questions: do the extended properties now sit in a set named after the host instead of Other; do the mapped parameters in your user-defined file actually appear; does the IFC parameters dialog open on a family type; and do Show Parts walls, plus IFC2x3 and IFC4x3 wall geometry, overlay the coordination model you already trust.
Do not rewrite the BEP because Other changed its name. Do not treat a parts export as the federated model. Confirm Help > About before you tell the project the office is on 27.4.
Start with Autodesk’s 27.4.0.30 notes and the user-defined property set article.
Frequently asked questions
Is 27.4 actually public, or is this still a Dutch support note?
The Autodesk/revit-ifc releases page now lists Release 27.4.0.30 for Revit 2027. GitHub dated the tag 30 October 2026. The previous public 2027 build was 27.3.0.12 on 13 August. The Dutch RVIPS note that day only pointed at the same tag. Confirm Help > About after you install the MSI.
Does this replace the IFC exporter that came with Revit 2027?
Yes, that is the point of the open-source add-in. Autodesk’s README says it overrides the standard version shipped with Revit and its updates, and that builds from 2023 onward can also appear in the Autodesk Desktop App depending on your licence. Install the 27.4 MSI from the release, or wait for that channel if that is how the office patches. Then export from a non-sensitive job and read the add-in version before you change the BEP.
Will every shared parameter now land in a named property set?
No. The notes only move extended properties out of Other and into a set named after the element that contains them. User-defined property sets still need the mapping file or the 2027 IFC parameter mapping. One 27.4 fix is that some mapped parameters were not writing. Do not treat a full Revit property-set dump as the issued exchange. Check the named sets in the viewer you already trust.
Is the wall geometry now safe to issue?
Not automatically. The notes fix a wall that moved when you exported with Show Parts, and incorrect wall geometry on IFC2x3 and IFC4x3. Overlay the same walls in Solibri, BIMcollab or Simplebim before you tell a contractor the parts model is the coordination file. Keep the issued package named, dated and approved.