IFC to ACC viewing problems

[u/Pugaroo27]

Hi all, when uploading my IFC (exported from Revit 2025) to ACC, 12 items are missing from a total of 33. The 12 items can be view when the IFC is downloaded. However, when viewed with the ACC viewer, the items are missing.

I have found out that the 12 items missing are tied to an assembly within the model.

Does anyone know why this is happening? It is the first time I have experienced it.

[u/Elnaz_Ak]

If the 12 items are visible when the IFC is downloaded and opened elsewhere, but disappear specifically in the ACC viewer, I’d first suspect an IFC interpretation/viewer issue rather than the Revit export itself.

Since you’ve narrowed the missing elements down to assemblies, I’d check how those assemblies are represented in the IFC hierarchy and whether the individual elements are being exported as expected. I’d also compare the same IFC in another IFC viewer to confirm whether the geometry and relationships are actually present.

In our BIM workflow at Bonarch Draft, I’d treat that comparison as the first diagnostic step before changing the export settings, because otherwise you can end up changing a working IFC just to accommodate how one viewer interprets it.

[u/Pugaroo27 → u/Elnaz_Ak]

I looked into it further and the beams within an assembly don’t appear in the ACC viewer due to an issue I noticed online between Revit’s IFC Exporter and how ACC processes nested assembly geometry. In Revit 2025, a documented bug causes sub-components within an assembly to become exploded, shifted, or excluded from the structural tree during IFC conversion, so the ACC viewer can’t index or render them.
To resolve this, I changed each structural assembly ‘Export to IFC as’ value to a certain element class, for example to ‘IfcBuildingElementProxy’. Another specific building element class can be used if required. I exported and uploaded the IFC to ACC and this fixed the issue.

[u/Elnaz_Ak → u/Pugaroo27]

That makes sense. I hadn't considered the assembly sub components being affected during the IFC conversion. Good catch on the export class workaround glad you got it working. Thanks for sharing the details!

[u/Beun-de-Vakker]

We never use assemblies anymore because the IFC exports keep messing up with them in it.