[vtkusers] Python wrapping

[Gib Bogle]

Thanks David.  'import vtkCommonPython' works, as do several other modules.  Meantime I looked more closely at the depends info and realized that it was finding 32-bit Qt libraries.  Putting the 64-bit Qt directory at the start of PATH fixed that, and now it works :)  I guess vtkRendering needs Qt while several of the others do not.

It really is a nuisance having both 32-bit and 64-bit libraries on my system, but I cannot switch completely to 64-bit, for various reasons.

Thanks for your help
Gib
________________________________
From: David Gobbi [david.gobbi at gmail.com]
Sent: Monday, 3 November 2014 10:52 a.m.
To: Gib Bogle
Cc: vtkusers at vtk.org
Subject: Re: [vtkusers] Python wrapping

Hi Gib,

Yes, the .pyd files should be in the PYTHONPATH and the DLLs
should be in the PATH.  That's all that should be needed.

My best guess is that it is failing to load vtkRenderingPython.pyd
itself, and it you hadn't specifically told me that both your python
and your VTK are 64-bit, my guess would be that it was trying to
load a 64-bit .pyd file into a 32-bit python.

Try to see if you can load the .pyd files directly, by doing this in python:

  import vtkCommonPython

When that fails, it should provide a more meaningful error message.
In any case, it's always best to start testing with the module that has
the fewest dependencies (i.e. Common) and then work up from there.

The vtk*PythonD.dll files have all the code that actually translates
python method calls into VTK C++ method calls.  But they aren't
python modules (i.e. they have no python "init" method).  They are,
in essence, the back-end of the wrappers while the vtk*Python.pyd
files are the front-end.

 - David




On Sun, Nov 2, 2014 at 1:51 PM, Gib Bogle <g.bogle at auckland.ac.nz<mailto:g.bogle at auckland.ac.nz>> wrote:
Hi David,

Thanks for that clarification.  I don't know much about Python, and less about Python wrapping in VTK.

I have no idea why the simple example program fails.  The code is:
 http://www.vtk.org/Wiki/VTK/Examples/Python/Visualization/ProgGlyph
with the first line changed (or removed - it makes no difference).

PYTHONPATH includes C:\vtk-vs10-x64\lib\site-packages\vtk, and all the .pyd files are there.

The first entry in PATH is C:\vtk-vs10-x64\bin.  Do I need any other VTK directories in the path?

In the error message, repeated below, can you tell me for which DLL does the DLL load fail?

D:\testing\VTK\Superquadric>vtkpython superquadric.py
Traceback (most recent call last):
  File "superquadric.py", line 3, in <module>  import vtk
  File "C:\VTK-VS10-x64\lib\site-packages\vtk\__init__.py", line 63, in <module> __helper.refine_import_err('rendering', 'vtkRenderingPython', exc)
  File "C:\VTK-VS10-x64\lib\site-packages\vtk\__helper.py", line 32, in refine_import_err raise LinkError, str(exc)
vtk.__helper.LinkError: DLL load failed: %1 is not a valid Win32 application.

Both python27 and VTK are 64-bit.

By the way, what are the vtk*PythonD.dll files?

Thanks
Gib
________________________________
From: David Gobbi [david.gobbi at gmail.com<mailto:david.gobbi at gmail.com>]
Sent: Monday, 3 November 2014 2:18 a.m.

To: Gib Bogle
Cc: vtkusers at vtk.org<mailto:vtkusers at vtk.org>
Subject: Re: [vtkusers] Python wrapping

Hi Gib,

The vtk*Python.pyd files are the DLLs that you are looking for.  See here:
https://docs.python.org/2/faq/windows.html#is-a-pyd-file-the-same-as-a-dll

 - David

On Sun, Nov 2, 2014 at 12:09 AM, Gib Bogle <g.bogle at auckland.ac.nz<mailto:g.bogle at auckland.ac.nz>> wrote:
Hi David,

All the .pyd files are where they should be, and all the vtk*PythonD.dll files are where they should be, in C:\vtk-vs10-x64\bin, which is in the PATH.  The point of my question was that the VTK release build did not create any vtk*Python.dll files, although it did create the .lib files.  Correct me if I'm wrong, but I think that vtkpython is looking for the missing DLL files - specifically, for vtkRenderingPython.dll.  Am I wrong in thinking that they should have been built?

Gib
________________________________
From: David Gobbi [david.gobbi at gmail.com<mailto:david.gobbi at gmail.com>]
Sent: Sunday, 2 November 2014 4:11 p.m.
To: Gib Bogle
Cc: vtkusers at vtk.org<mailto:vtkusers at vtk.org>
Subject: Re: [vtkusers] Python wrapping

Hi Gib,

The python modules are called "vtk*Python.pyd" on Windows.
On your system, I'm guessing that they should be in this directory:
c:\VTK-VS10-x64\lib\site-packages\vtk

And, in order for the modules to be loaded, all of the VTK DLLs
must also be in your PATH.  Either that, or you can copy them all
into c:\VTK-VS10-x64\lib\site-packages\vtk so that the .pyd files
will be able to find them there.

The vtk*PythonD.dll files are not python modules, they are support
libraries that are needed by the python modules.

 - David



On Sat, Nov 1, 2014 at 8:54 PM, Gib Bogle <g.bogle at auckland.ac.nz<mailto:g.bogle at auckland.ac.nz>> wrote:
I just rebuilt VTK-5.10.1 64-bit on Windows with VTK_WRAP_PYTHON ON.  The build completed without errors.  I do not understand why I have 14 .lib and .dll files named vtk*PythonD.dll and vtk*PythonD.lib, and 14 .lib files named vtk*Python.lib, but no vtk*Python.dll.  This causes my attempt to run a VTK-Python example to fail like this:

D:\testing\VTK\Superquadric>vtkpython superquadric.py
Traceback (most recent call last):
  File "superquadric.py", line 1, in <module>  import vtk
  File "c:\VTK-VS10-x64\lib\site-packages\vtk\__init__.py", line 63, in <module>  __helper.refine_import_err('rendering', 'vtkRenderingPython', exc)
  File "c:\VTK-VS10-x64\lib\site-packages\vtk\__helper.py", line 32, in refine_import_err raise LinkError, str(exc)
vtk.__helper.LinkError: DLL load failed: %1 is not a valid Win32 application.

I see that somebody was asking exactly the same question back in October, 2010, but there was no answer.

Any suggestions?

Thanks
Gib



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