[Paraview] scripting beginner

[Tim Gallagher]

Without looking at the script in detail, have you tried using the Python Trace feature in the GUI? Since, at this stage anyway, all of your tasks are straight forward, you can do them in the GUI with the trace turned on, then look at the resulting script to show you how all of it is done. 

That is, by far, the easiest way to learn how to script Paraview.

Try the following script:

 >from paraview.simple import *
 >
 >rv = GetRenderView() # Get a connection to the render window
 >reader = OpenDataFile(PATH+'lfff00300000p_QC.vts')
 >reader.Update() # Actually read the file in and update the pipeline
 >contourFilter = Contour(reader)
 >contourFilter.ContourBy = 'velocity'
 >contourFilter.Isosurfaces = [0.0005, 0.001]
 >dr = Show() # Update the pipeline again, but we need to alter how it looks
 >lookupTable = CreateLookupTable( RBGPoints=[<minval to show>, 0.0, 0.0, 0.0, <maxval to show>, 1.0, 1.0, 1.0], VectorMode='Magnitude', ColorSpace='RGB', ScalarRangeInitialized=1.0) # This creates the color map, going from back to white
 >dr.ColorArrayName = '<data array name to show>' # Tell it how you want contours colored
 >dr.ColorAttributeType = '<POINT_DATA or CELL_DATA>' # Tell it the type of data it is coloring
 >ResetCamera()
 >WriteImage('picture.png')
 >servermanager.SaveState('pythonstate.pvsm')

That is something like what you need to do (I can't promise it works, but it will get you close -- I've never used a script with the Contour filter). Again, do what you are trying to do in the GUI with trace turned on and see what it outputs. You'll see some extra steps along the lines of what I added that should get you up and running.

Tim

----- Original Message -----
From: "Hartwig Anzt" <hartwig.anzt at kit.edu>
To: paraview at paraview.org
Sent: Saturday, February 19, 2011 9:15:35 AM
Subject: [Paraview] scripting beginner

Hi!

I am real beginner in paraview scripting. Up to now, I used the paraview 
graphic platform, but since the tasks are getting more complex, I wanted 
to use paraview scripting with python.... and failed.

What I want to do:
- Load .vts-data
- Create Contour
- Set Data Range
- Save State/Save Picture

I wrote the following script:

 >from paraview.simple import *
 >
 >reader = OpenDataFile(PATH+'lfff00300000p_QC.vts')
 >contourFilter = Contour(reader)
 >contourFilter.ContourBy = 'velocity'
 >contourFilter.Isosurfaces = [0.0005, 0.001]
 >Show(contourFilter)
 >ResetCamera()
 >WriteImage('picture.png')
 >servermanager.SaveState('pythonstate.pvsm')


If I run the script, two errors occur, probably with the same reason.
The writer says:
vtkSMRenderViewProxy (0x1e6da30): Disabling offscreen rendering since 
empty image was detected.

When I open the state, there is nothing displayed. in order to see 
anything, I do have to press "Apply" for the Contour filter and "Reset" 
for the Camera, then everything looks fine.

How can I implement, that these two operations are conducted?

Thanks, Hartwig

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Karlsruhe Institute of Technology (KIT)
Engineering Mathematics and Computing Lab (EMCL) &
Institute for Applied and Numerical Mathematics 4

Dipl.-Math. techn. Hartwig Anzt
Research Associate

Fritz-Erler-Str. 23, Geb. 01.86
76133 Karlsruhe, Germany

Phone: +49 721 / 608 - 45849
Email: hartwig.anzt at kit.edu
Web:   http://numhpc.math.kit.edu, http://emcl.kit.edu, 

KIT - University of the State of Baden-Wuerttemberg and
National Laboratory of the Helmholtz Association

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