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New IFC writer to re-write ifcPresentationLayer

  • April 23, 2026
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kevins0625
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Hi,

I was hoping to use the new IFC writer available in FME 2026.1 to update the IfcPresentationLayer attribute values from IFC to IFC.

The idea was to disregard the current layers exported from Revit from others and define our own layer presentation for the models so we can turn certain layers on and off in our platform (Trimble Connect). 

I used the reader to load the IFC file (in 2x3 format), and it successfully retrieved all layer attributes into FME. However, I don’t seem to be able to write the updated layers.

In fact, even without adding any transformers—just using the reader and writer from IFC to IFC—the layers are lost.

 

So I’m wondering if anyone has had success using the latest FME reader and writer for rewrite the layers

Thanks!

Best answer by crystalatsafe

Hi ​@kevins0625 

Our team is currently making a few changes to IFCPresentationLayer support that are targeted to be fixed for 2026.2 (Internal reference: FMEENGINE-87705). I can let you know as soon as this is released! 

    5 replies

    kevins0625
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    • kevins0625Contributor
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    • April 23, 2026

    I opened the two IFC files (original and exported) in Notepad. I can see that the exported file still includes the IfcRepresentationAssignment information, but it doesn’t include any element IDs, whereas the original file includes the elements IDs for each layer.

     

     

    It might be possible that the IFC_API writer doesn’t write the list of elements IDs included in the original file.

    crystalatsafe
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    • crystalatsafeSafer
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    • April 28, 2026

    Hi ​@kevins0625 

    Our team is currently making a few changes to IFCPresentationLayer support that are targeted to be fixed for 2026.2 (Internal reference: FMEENGINE-87705). I can let you know as soon as this is released! 

    kevins0625
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    • kevins0625Contributor
    • Author
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    • April 30, 2026

    Hi ​@kevins0625 

    Our team is currently making a few changes to IFCPresentationLayer support that are targeted to be fixed for 2026.2 (Internal reference: FMEENGINE-87705). I can let you know as soon as this is released! 

    Thank you! that would be a game changer for this writer.

    It would also be awesome if we could create/delete layers and reorganise them based on attributes such as element IDs. It’s surprising that many users still rely on layers to control what they see on screens.

    crystalatsafe
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    Hi ​@kevins0625 

    Yes! We will be able to create IfcPresentationLayers and allow for linking whatever elements you like to them via ID attributes. 

    To delete a layer, you can simply not send the PresentationLayerAssignment features in question to the writer and make sure not to link to them on individual features, and they won't be created in the output file.

    crystalatsafe
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    Hi ​@kevins0625 

    I wanted to provide an update that this is now targeted for the 2026.3 release to allow sufficient time for thorough QA. Thank you for your patience! I will let you know as soon as it is released. 

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