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Creating an IMDF File from a DWG File Without Xrefs

  • Oct 6, 2026 7:33 AM UTC
  • 1 reply
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stigloher2010
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Hello,

I have a task to evaluate whether it is possible to create an IMDF dataset from DWG files using FME.

There is a good tutorial from Safe Software (Converting CAD Datasets to IMDF: Part 1 – FME Support Center) that uses a master drawing file with Xrefs. However, in my case I only have separate DWG files for each floor, so I cannot replicate the tutorial in exactly the same way.

At the moment, I do not have access to AutoCAD and I am not a CAD expert. I have read that properly converting DWG data into the IMDF format can be quite challenging. Does anyone have experience with or examples of an FME workflow that does not use Xrefs, but instead uses separate DWG files for each floor? Or do you think that creating a valid IMDF dataset from this kind of source data is not feasible without further preparation of the DWG files?

Thanks in advance!

1 reply

daveatsafe
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  • daveatsafeSafer
  • Safer
  • Oct 6, 2026 11:13 PM UTC

Hi ​@stigloher2010,

If your DWG files are all scaled and aligned properly to each other, then you can simply all of them in with a single AutoCAD reader. Expose the format attribute fme_basename on the input feature type(s) so FME will store the source file name on the data, which will allow you to distinguish between the floors later in the process.

After you have added the single reader reading from the multiple files, route the features to an Inspector transformer, then run the workspace. This will display the features and let you ensure that they are properly aligned and scaled. If so, continue on with the process in the article after the reading Xref steps.

If the files are not properly aligned, try to find a common reference location between the floors. Elevator shafts and stairwells are good candidates. Note the coordinates for the different floors, and calculate the X and Y offsets needed to move from the reference floor to each of the other floors. You can then use an AttributeFilter to route the different floors to individual Offsetters to apply the correction offsets needed to align them.

If you like, I would be happy to examine your DWG files, and advise you if they are properly aligned, and if they contain the appropriate information needed to convert to IMDF. If you don’t want to publicly share your data, please follow  up with me at dave.campanas@safe.com.

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