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BB: upgrade/downgrade between IFC4 or IFC2x3

1. T by theoryshaw on 16 Feb 2022, edited 15 Mar 2022 #

   Is there a relatively easy way to upgrade/downgrade between IFC4 or IFC2x3, with BB?

2. C by Coen on 16 Feb 2022 #

   I just did an attempt with your model from the other thread.

   Openened two sessions of BlenderBIM,

   • Imported the IFC4 in one session

   • Started a New IFC2x3 project in the other BlenderBIM sessions

   • Copied all the meshes to the IFC2x3 project.

   • Tried to re-assign all the meshes/IFC elements

   Got this error:

   
   AttributeError: entity instance of type 'IFC2X3.IfcPolyLoop' has no attribute 'Name'
   

   Now it's beyond my knowledge. I'm tempted to say it's not possible.

3. C by Coen on 16 Feb 2022 #

   Tried to ignore all the error warnings and kept on going, by when I wanted to export the IFC2x3. I got this warning

   AttributeError: entity instance of type 'IFC2X3.IfcFaceOuterBound' has no attribute 'ContextOfItems'

4. C by Coen on 16 Feb 2022, edited 16 Feb 2022 #

   I succeeded half, but it an extremely hacky way and probably lost all the data attached to the IFC elements.

   

5. G by Gorgious on 16 Feb 2022, edited 16 Feb 2022 # +3 votes

   I think there is an IfcPatch recipe just for this, I can't show a screenshot right now though.

   This is the code for the patch (I think), for information :

   https://github.com/IfcOpenShell/IfcOpenShell/blob/v0.7.0/src/ifcpatch/ifcpatch/recipes/Migrate.py

   First argument should be the schema name.

6. B by Bimlooser on 16 Feb 2022 # +3 votes

   Hope it helps

   

7. M by Moult on 20 Feb 2022 #

   Yeah so the Migrate IFC patch does a pretty swell job at upgrading IFC2X3 to IFC4 (specify ["IFC4"] as an argument). However, although in theory it can downgrade, it would likely fail on a real project (it'll work for small subsets of data, though). This is because I never wrote the code to handle downgrading certain IFC4 geometry types since I never needed it and it was more urgent to upgrade than downgrade.

   But let me know if you need downgrading and I can find a bit of time to implement it. It's pretty straightforward, just another item in the endless todo list.

8. M by Moult on 20 Feb 2022 # +9 votes

   What's pretty awesome too is that in the latest BlenderBIM Add-on builds since this is such a common thing, there is now a one-button upgrade whilst you're loading files:

   

9. L by lukas on 15 Mar 2022 #

   the argument for downgrading is then 'IFC2X3' ?

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