Unicode characters problem in AutoCAD 2025

[ziggy63]

Hi to all,

In my applications I use both VB.NET and AutoLISP. Some VB.NET applications create temporary text files (*.txt) that are then read by a Lisp function. As I live in Greece, these files include many Unicode characters. After having upgraded my BV.NET projects from .NET Framework to .NET 8.0, the Unicode characters are not read correctly by Lisp. For example, this is a screenshot from AutoCAD 2024:

And this is the same screenshot from AutoCAD 2025:

I haven't changed anything in my VB.NET projects, I have just upgraded them, using the Upgrade Assistant. To create the temporary files, I use the "FileOpen" function. When I open the txt file with Notepad, the Unicode characters appear correctly (for example "Δ" or "%%c"). But when Lisp opens the file, it produces gibberish. I know that all this sounds... Greek to you, but does anybody know why this is happening? Does "FileOpen" behave differently in .NET than it does in .NET Framework?

Thanks in advance,

ziggy63

[Alfred.NESWADBA]

Hi,

not sure to be able to help, but I would start with differentiating if the issue is from your VB.NET code now writing the LISP file (content of the LISP file has already issues) or running the LISP then in AutoCAD 2025.

Let your VB.NET code for 2024 write the LISP-file, then run the LISP in AutoCAD 2025 ... and vice versa:

Let your VB.NET code for 2025 write the LISP-file, then run the LISP in AutoCAD 2024

When do you now see the issues?

- alfred -

[ziggy63]

Hi Alfred,

I tried what you suggested and the result is the same: the culprit is VB.NET for AutoCAD 2025. The problem has to do with the encoding of the txt file. In the previous versions of AutoCAD, the encoding of the file was "ANSI", now it is "UTF-8". So, if I find out how to change the encoding of the text file created by of the "FileOpen" function, the problem will be solved.

Best regards,

Ziggy63

[daniel_cadext]

I thought you could specify encodings in .NET?

Maybe use StreamReader, StreamWriter with System.Text.Encoding

[kerry_w_brown]

You may need to look at this:

https://help.autodesk.com/view/OARX/2025/ENU/?guid=GUID-AC74D827-0969-4888-91C0-C3149DEC3659

and the LISPSYS system variable determines if AutoLisp treats strings as ANSI or UTF-8

. . . probably worth checking.

[ziggy63]

Hi Kdub,

I don't think it has to do with AutoLisp. After all, my applications worked fine in previous versions of AutoCAD (2024 and prior) with LISPSYS = 0. I will try changing the encoding of the text file while creating it in VB.NET.

Thank you all for your answers.

[kerry_w_brown]

Hi @ziggy63 

Refer the  Comparison with other encodings section

https://en.wikipedia.org/wiki/UTF-8#See_also:~:text=of%20invalid%20input.-,Comparison%20with%20other...

If you are using UTF-8 for Greek characters I can't imagine why you would force AutoLISP to read the strings as ACSII by using LISPSYS = 0 ??

added :

Though, I must admit, the documentation in the AutoLisp docs is a little vague regarding the requirements.

Regards,

[kerry_w_brown]

@ziggy63,

as @daniel_cadext mentioned, how are you writing the file ??

perhaps try something like  :

https://learn.microsoft.com/en-us/troubleshoot/developer/visualstudio/csharp/language-compilers/read...

Regards,

[ziggy63]

Yes, I think I will change the way I create the text file, and hope this will solve the problem.

Thanks,

ziggy63