segmentation fault when visualizing vtk file in linux sever

ParaView Support
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1

Hello, I’m trying to visualizing vtk file in linux server for automation.
So, I got python script from paraview in window version ‘Tools - Start trace’.

I’m doing quite simple job. ‘Contour’, change ‘Coloring’ as a solid color and 'Save screenshot
The traced python script works at my window and mac computer (pvpython *.py), but returns a segmentation fault at Linux server.

Paraview version information are:

Windows: ParaView 5.9.1-Windows-Python3.8-msvc2017-64bit
Mac: Paraview 5.9.1-MPI_OSX10.13-Python3.8-64bit
Linux: ParaView 5.9.1-MPI-Linux-Python3.8-64bit

I attached python script (pv_script_from_trace.py) and sample vtk file (sample.vtk).
pv_script_from_trace.py (6.0 KB)
sample.vtk (2.1 MB)

I used the following command,
$ pvpython pv_script_from_trace.py
When I’m using this one in linux system, attatched segmentation fault occurs

error_message
error_message999×1611 178 KB

Probably, the error occurs at ‘SaveScreenshot’ part in line 139 of python code.
Why is it happen? Can anyone help me to solve this problem?

2

Do you have X running or are you running it via ssh or via schedule job?

3

Thank you for reply.
I’m running at terminal connected by ssh.

4

Then that explain why.

Long story short, ParaView depend on OpenGL and we depend on X, EGL or OSMesa to provide us the graphic context.

The default paraview (Qt) assume X (for linux). But in your case, X is not started or at least you don’t have a DISPLAY defined in your SSH terminal. So at that point, when pvpython try to create the graphic window (offscreen) it fails since X is not around.

For doing headless operations (and when X is not running), you need to use a build of ParaView that is headless (https://www.paraview.org/download/?version=v5.11&filter=Linux&tags=OFFSCREEN).

But the EGL require nvidia GPU while OSMesa is CPU only (slow but works everywhere).

HTH,

Seb

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5

Thank you for your claer explanation Jourdain!

It worked by headless version (osmesa) of Paraview.
Finally I can automate visualization process.

Thanks a lot!

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6

I’m not 100% sure, but I think we bundle mesa in our graphic version. So you might be able use your default paraview by just adding --mesa as argument when running headless script.

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