Strange pattern on insulation after exporting the installation to IFC

[jakub_nonnaFKMLK]

After exporting the model to IFC, something like a pattern is created on the insulation. I have already spent a long time to get rid of it however in vain. Is there any way to get rid of these lines?

[Attila.Kalina]

I just noticed this as well in export from R22.
The insulation is not exported as a profile extrusion but as a triangulated mesh.
I suspect this affect export speeds as well and may well be the reason behind this:
https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/IFC-export-stuck-o...

Any workaround aside from version update Which is not possible due to project limitation?

[jakub_nonnaFKMLK · Accepted solution]

In my case, the solution turned out to be changing the IFC version to IFC4 Design Transfer View [Unofficial]. This type of export creates “boundaries” by which the display of irregular shapes (in my case, isolations) changes, and the file size decreases (in my case, the file size decreased by 2x, depending on the amount of isolations in the model).

This is the end result

[Attila.Kalina]

Thank you, sounds promising.
I'll see how that works.
I've been reluctant so far to try IFC4 as last tests had weird results with elements not exporting.

[Attila.Kalina]

Run a test with IFC4 design transfer, and indeed the strange triangulation of the insulation is gone.
Size is down as well, not as drastically but still.
It did not help with the lockup of the export though, it took about 4 hours to export the 25k-ish elements of a 4 story hvac model.

[Attila.Kalina]

Except, now i have weird shifted fittings on IFC4, maybe the following issue?
https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Element-shifted-ex...
Solution Revit 2025 or export model to IFC2x3.  Here we go again:)