Python scripting with ParaView3

ParaView and Python

ParaView offers rich scripting support through Python. This support is available as part of the ParaView client (paraview), an MPI-enabled batch application (pvbatch), the ParaView python client (pvpython) or any other Python-enabled application. Using Python, users and developers can gain access to the ParaView engine called Server Manager.

The user can access the whole ParaView functionality and combine it with the power of the Python scripting language.

Use cases include but are not limited to

• Batch file conversions

ParaView Scripting tutorial explains how to access ParaView functionality using Python.

Example scripts

convert_vtk_to_vtu.py

Convert a legacy VTK text file to VTU XML file.

"""Demo script that converts a legacy VTK file to a VTU file.
"""

from paraview import servermanager

INPUTFILE = "/afs/psi.ch/sys/linux/opt/paraview/data/paraview_data-3.2beta/Data/blow.vtk"
OUTPUTFILE = "blow.vtu"

# create a built-in connection
if not servermanager.ActiveConnection:
    connection = servermanager.Connect()

# create reader for legacy VTK files
reader = servermanager.sources.LegacyVTKFileReader(FileNames=INPUTFILE)

# create VTU writer and connect it to the reader
writer = servermanager.writers.XMLUnstructuredGridWriter(Input=reader,
                                                         FileName=OUTPUTFILE)

# Trigger execution of pipeline
writer.UpdatePipeline()

The script can be started e.g. as follows:

module load paraview/3.3_dev-osmesa
pvpython convert_vtk_to_vtu.py

Notes: You need to use a paraview installation that is compiled with Python support.

convert_vtk_series_to_pvd.py

Convert a series of legacy VTK files (time-steps) to the PVD file format.

"""Demo script that converts a series of legacy VTK files (time-steps) to a PVD file
referencing a series of VTU files.
"""

import os
from paraview import servermanager

OUTPUTFILE = "/scratch/geus/emtbos.250.pvd"

def get_input_file_list(time_steps):
    "Create list of vtk files to be converted"
    input_dir = "/scratch0/shared/oswald/cedp/emtbos.250/numsol_0"
    file_list = []
    for step in time_steps:
        vtk_file = os.path.join(input_dir, "pitdi250tsno%d.vtk" % int(step))
        file_list.append(vtk_file)
    return file_list

def vtk_to_vtu(in_file, out_file):
    "Convert one vtk file to a vtu file"
    reader = servermanager.sources.LegacyVTKFileReader(FileNames=in_file)
    writer = servermanager.writers.XMLUnstructuredGridWriter(Input=reader,
                                                             FileName=out_file)
    writer.UpdatePipeline()

def main():
    "main program"
    # create a built in connection
    if not servermanager.ActiveConnection:
        connection = servermanager.Connect()

    # get list of vtk files
    time_steps = range(0, 5000)
    vtk_files = get_input_file_list(time_steps)

    # convert to vtu and create pvd file
    out_dir = OUTPUTFILE + ".d"
    try:
        os.mkdir(out_dir)
    except:
        pass
    f_out = file(OUTPUTFILE, "w")
    f_out.write("""<?xml version="1.0"?>
<VTKFile type="Collection" version="0.1" byte_order="LittleEndian" compressor="vtkZLibDataCompressor">
  <Collection>
""")
    for i, in_path in enumerate(vtk_files):
        in_dir, in_file = os.path.split(in_path)
        out_path = os.path.join(out_dir, os.path.splitext(in_file)[0] + ".vtu")
        print "Converting %s to %s" % (in_path, out_path)
        vtk_to_vtu(in_path, out_path)
        f_out.write('    <DataSet timestep="%d" group="" part="0" file="%s"/>\n' % (i, out_path))
    f_out.write("""  </Collection>
</VTKFile>
""")
    f_out.close()

if __name__ == "__main__":
    main()

The script can be started e.g. as follows:

module load paraview/3.3_dev-osmesa
pvpython convert_vtk_series_to_pvd.py

Notes: You need to use a paraview installation that is compiled with Python support. The script only works if you have read access to the directory /scratch0/shared/oswald/cedp/emtbos.250/numsol_0