"Active Document is Not a Part Document" Issue in Autodesk Inventor

[svloFNWW9]

Dear all,

I hope this message finds you well. I am writing to seek assistance regarding an issue I’ve encountered while trying to programmatically interact with Autodesk Inventor via Python scripts using the Inventor API.

Problem Description

While attempting to process a Part Document (.ipt) using the API, the script consistently returns the following error:

"Active document is not a Part Document. Please open a Part (.ipt) file."

What I Have Tried

1. Verified that the correct file (Part.ipt) is located in the target directory.
2. Manually opened the Part Document in Autodesk Inventor before running the script.
3. Attempted to explicitly activate the Part Document in the script using:
   python

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   part_doc = inventor_app.Documents.Open(part_file_path) inventor_app.ActiveDocument = part_doc
4. Confirmed the document type with:
   python

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   part_doc.DocumentType
   The result is 12290, which doesn’t match the expected value for a Part Document (2).

Environment Details

• Autodesk Inventor Version: 2025
• Python Version: 3.13.1
• Operating System: Windows 11 Pro
• API/Library: PyWin32 for COM interaction

Expected Behavior

The script should identify the active document as a Part Document and proceed with further processing without errors.

Request for Assistance

Could you please advise on:

1. Whether the document type 12290 indicates a specific issue or misconfiguration?
2. Steps to ensure the Part Document is correctly recognized by the API.
3. Any additional settings or adjustments required in Autodesk Inventor for seamless API interaction.

If necessary, I can provide sample code or additional details about the environment and workflow.

Thank you for your time and support. I look forward to your guidance on resolving this issue.

Best Regards,

[A.Acheson]

Hi @svloFNWW9 

I would have thought it unnecessary to set the active document = to itself as this might have unintended outcome. 

For the number this is the enum value for the part document which checks out. 

kPartDocumentObject

12290

Part Document

You should be able to use from this point on 

The set variable part_doc

[marcin_otręba]

I  do not know python but i do not really understand if you did it correctly here :

part_doc = inventor_app.Documents.Open(part_file_path) inventor_app.ActiveDocument =part_doc

active document is read only:

maybe it should be :

part_doc = inventor_app.Documents.Open(part_file_path) 

[C_Haines_ENG]

The "Active Document" is the file that is currently selected and opened in Inventor. If that file is not a part document, you will get this error.