Encoding bug on dgn import

Rhino Rhino for Windows
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Hi,

I am running into a specific text encoding bug when importing DGN files containing Central European (Czech) characters into Rhino 8 (also tested and present in Rhino 7). The issue affects both Layer Names and Geometry Text.

There are two parts to this bug:

1. Windows-1250 read as Windows-1252 (Fixable via script) Rhino’s DGN importer seems to default to a Western European dictionary (ISO-8859-1 / Windows-1252) instead of respecting the Central European code page (Windows-1250).

  • As a result, characters like č, ř, ž are imported as è, ø, ž.

  • The data itself survives the import, and I am able to successfully fix these using a Python script that forces the string back to cp1250 character by character.

2. Uppercase “Š” is completely deleted on import (Unfixable) While the script fixes the rest of the alphabet, the uppercase Š is completely missing from the imported text.

  • In Windows-1250, uppercase Š is byte 0x8A (decimal 138).

  • It appears the Rhino DGN parser hits this specific byte, fails to recognize it (likely treating it as an invalid C1 control character), and aggressively strips it from the string entirely before the file finishes importing.

  • Because the data is physically deleted during import, it cannot be recovered or scripted afterward. (Note: lowercase š, byte 0x9A/154, survives the import and can be scripted).

I have tested this with multiple DGN files from different sources and confirmed the 0x8A byte is consistently dropped by Rhino’s importer.

Could the development team look into tweaking the DGN parser so it stops stripping the 0x8A byte? Or, ideally :slight_smile:, it would be great if the importer could automatically detect or allow the user to specify the Windows-1250 code page during import to prevent the Mojibake entirely.

For a reference, I am attaching a dgn file containing “Š” (along other critical characters).

I am running Rhino on Version 8 SR27
(8.27.26019.16021, 2026-01-19)
in default English language UI.

Thank you greatly! :smiling_face_with_three_hearts:

762385.zip (2.4 MB)

For anyone in need I have pinned the script into a github public repo.