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Working with reference files in DGN (v8) reader/writer

  • November 26, 2025
  • 1 reply
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ipuskaric
Participant
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Hello, I have a question regarding the DGN Reader/Writer about reading and writing external reference files.

I am using the DGN Reader that contains a reference to another DGN file. In that referenced file there is a rectangle (an igds_shape element). In the DGN Reader parameters I enable the options "Read Elements From Reference Files" and "Keep Elements That Represent Reference Files".

My goal is to move that rectangle to a different location and save it into a DGN file in such a way that:

  • the rectangle appears at the new (correct) position - this part is not a problem; I already have a workbench for moving the geometry
  • but it still keeps the link to the original referenced DGN file,
  • and the referenced DGN file itself remains unchanged.

In other words, I want to move the geometry in the main DGN while keeping the external reference link attached to it, so that any future changes in the referenced file (e.g., adding an image inside that rectangle) automatically appear in the main DGN at the updated location.

I need to perform this operation for more than 500 DGN files, so creating a new reference file for every moved geometry is not an option.
Also, I cannot provide example files because the data is confidential.

Could you please advise whether this workflow is possible in FME, and if so, how it should be configured?

Thank you!

    1 reply

    pierrekoelich
    Safer
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    Hi ​@ipuskaric ,

     

    Apologies for the delayed response. I’ve recently spent some time looking at your problem, and think that FME is able to do this, with a caveat.

    I’ve attached a workspace that demonstrates this, here are some things to watch out for and note:

    • When reading in the .dgn file, ensure that the option: Keep elements that represent reference files(V8 only) is on, but DO NOT read in the elements from the reference files. This makes it simpler for you as you are changing the values for all xrefs that are represented by that feature.
    • On read, make sure the format attributes that start with igds_xref are exposed, in the workspace I’ve attached, I changed igds_xref_rotation, igds_xref_scale, igds_xref_master_origin_x/y/z, and igds_xref_ref_origin_x/y/z.

     

    The caveat that due to an issue with one of the libraries that we use to read DGN, moving these xrefs can be blocked. This can reliably be seen when the AutoCAD Writer is invoked in the log. If you see a message containing Opening AutoCAD writer in the log, moving the externally referenced file will fail.

    For example, Zoom file to drawing extents being on will cause the translation to fail. A lot of functionality is restricted by this issue, some other examples would be item types and 3D geometry. We have an internal issue tracking this, reference FMEENGINE-98675

    If you would like to explore further, I would also highly recommend you submit a support ticket with us. We would also be able to take a closer look at your data in that context.

     

    Pierre

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