python import vtk hangs indefinitely

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1

I am trying to install vtk for use in Blender, which currently uses Python 3.11.11, via pip install vtk
the line “import vtk” causes python to freeze indefinitely, without ever throwing an error message.
If I attempt to type “from vtk import”, the autocomplete kicks in to look for suggestions, and again freezes before offering any.

My windows miniconda environment is running python 3.13.5, and after installing vtk exhibits the same behaviour. Reinstalling earlier versions has not helped, reinstalling using wheel has not helped. I can’t seem to get vtk running in any python environment, but never receive an error message.

My previous installation on Windows 10 worked without problem. I have just moved to a clean install of Windows 11 and found that everything hangs on import.

2

We do test import vtk before uploading, but only in a pip environment. import vtk imports all of VTK in one shot and, as such, it is preferred to instead use from vtkmodules import vtkCommonCore (for each module needed). Does this behave better for you? If so, perhaps you can use it to figure out which module is causing issues in your case.

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3

@JBarr you’ve marked this as solved. What turned out to be the cause of the hang?

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4

I haven’t located the cause of the hang; import vtk still doesn’t work on any of my environments.
I am able to run my script by importing only the submodules I need to use, which solves my simple use-case.

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