[Paraview] “Upload” vtk data from client to server in paraview script

[Oscar Wilsby]

Dear all,

I am relatively new to scripting in paraview using vtk wrappers. However one situation I always find myself in is writing a python script to be executed with pvpython and then having to include a miniature python script as an input to programmableFilters. As far as I understand, this allows the manipulation of pipeline data on the server side (so you don't have to retrieve data to the client) inside a tailored script. What I don't understand is why the process has to be so convoluted. At the very least it makes debugging very annoying as you don't know exactly where in the script that you input into the programmable filter a potential error might be. I have an example to illustrate.

Below are two pieces of code within an if/else switch where I add some temperature data to a vtkSphereSource. The first uses the programmableFilter approach and the second attempts to do the manipulation on the client side and then "upload/update" the server side. However the second approach does not result in any temperature data when I view it in paraview. What am I missing?



from paraview.simple import *
paraview.simple._DisableFirstRenderCameraReset()
import math
import vtk

use_prog_filt = False

# What I dont want to be doing:
if use_prog_filt:
    sphereSourceProxy = Sphere()
    renderView1 = GetActiveViewOrCreate('RenderView')
    sphereDisplay = Show(sphereSourceProxy, renderView1)
    sphereDisplay.ColorArrayName = [None, '']
    renderView1.ResetCamera()

    my_script= [
        'pdi = self.GetPolyDataInput()',
        'pdo = self.GetPolyDataOutput()',
        '',
        'temperature= vtk.vtkDoubleArray()',
        'npoints = pdi.GetNumberOfPoints() ',
        'for i in range(npoints):',
        '   x, y, z = pdi.GetPoint(i)',
        '   temperature.InsertNextValue(x)',
        'temperature.SetName("Temperature")',
        'pdo.GetPointData().AddArray(temperature)']


    programmableFilter = ProgrammableFilter(Input=sphereSourceProxy)
    programmableFilter.Script = str("\n".join(my_script))
    programmableFilter.RequestInformationScript = ''
    programmableFilter.RequestUpdateExtentScript = ''
    programmableFilter.PythonPath = ''

    programmableFilterDisplay = Show(programmableFilter, renderView1)

# What I want to be doing:
else:
    #sphereSource = vtk.vtkSphereSource()
    #print dir(sphereSource)

    sphereSourceProxy = Sphere()
    renderView1 = GetActiveViewOrCreate('RenderView')
    sphereDisplay = Show(sphereSourceProxy, renderView1)
    sphereDisplay.ColorArrayName = [None, '']
    renderView1.ResetCamera()

    pdi = servermanager.Fetch(input=sphereSourceProxy)
    npoints = pdi.GetNumberOfPoints() 

    temperature = vtk.vtkDoubleArray()
    temperature.SetName("Temperature")
    for i in range(npoints):
        x, y, z = pdi.GetPoint(i)
        temperature.InsertNextValue(x)
    pdi.GetPointData().AddArray(temperature)


    new_SphereSource = TrivialProducer()
    filt = new_SphereSource.GetClientSideObject()  # filter is a vtkTrivialProducer
    filt.SetOutput(pdi)
    new_SphereSource.UpdatePipeline()

    # The temperature data is available, but not in the paraview renderview...  
    print servermanager.Fetch(input=new_SphereSource)
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