Autodesk
PR: Export IfcSlab problem - strange behavior
Problem Description
We found a strange issue in export from Revit: When exporting whole project there are some elements not being exported and we could not identify why. Then we tried to isolate this element and found an issue → To describe and provide as much info as possible:
Problematic elements: Floors
- IFC2x3 → Exported correctly
- IFC4 RV (Arch) → Exported correctly
- IFC4 RV (Struc) → Exported correctly
- IFC4 DTV → Exported correctly
-
IFC4x3 → Error:
Problematic element is a Floor with opening and slope. (File saved here to replicate issue https://1drv.ms/f/c/1f30c6c2d1dbf645/EjtXB-dAzIhMg4MFtG6B31gBd328a7ww6h5TMdv3vpUIow?e=UIEWNL)
We have narrowed down all eventualities and found there are 3 factors that are somehow affecting export to IFC4x3.
- Slope
- Opening
- Material
Problem is being caused by material Default Floor! The very moment you delete this material (despite not being assigned to the element) export is working perfectly. That is the most strange thing about this bug - why Material, that is not being assigned to element, is causing problems if floor is exported and only if the floor has a slope and opening??
Combinations to clarify behavior:
- Slope + Opening - (Material deleted) → OK
- Slope + Material - (Opening deleted) → OK
- Opening + Material - (Slope deleted) → OK
- Slope + Opening + Material → Error
Thankfully we have found a simple fix (delete material from project), but this should be fixed if possible. To test it yourself download RVT file (v2024) and try to export to IFC4x3 → Error, if you then delete material "Default Floor" from Revit project → Export works miraculously.
Revit Version
2024.3.x
IFC for Revit Addon Version
24.2.2
Windows Version
11 24H2
We will take a look at this, thanks for the report. Also, good to see that IFC4.3 is starting to be used more!
@MisunMartin I am blocked from accessing that website to look at the file. Can you send it to me at [email protected]?
It is public accessible - no need to login. Anyway → File sent vie email
I can't reproduce this in my latest version but I'll see if it can be reproduced in older ones. Good news is that it appears to be fixed already, but will give more information soon.
Hello,
attached video showing versions and workflow with issues for IFC4x3 and working if one of the 3 effects (Slope/Opening/Material) is eliminated.
https://github.com/user-attachments/assets/7ed2167b-b3cf-4ba8-bd0b-3f78605ebf73
Tested it little bit more and figured out that this actually is the thing that is causing the trouble: EDIT: Tested it with 24.3.20 too → same as 24.2.20 = Error
If there is no Material set in "Object Styles" then even "Default Floor" material is not a problematic one and you do not need to delete it.
If there is a Material set in "Object Styles" floor then there is an export issue! Tested with original material and even fresh new everytime it caused and export error if Object Style material is being set.
OK, the good news is that this seems to be fixed in Revit 2025. Could you try that to verify? We will put this on our list of fixes to back-submit to Revit 2024.
Hello,
Revit 2025.4 with IFC 25.4.0.27 works fine.
Anyway possible "backfix" for 2024 would be awesome as there are many projects wtill running in v24.
Thank you!