vtk filter for OpenFOAM

Support
1

I want to filter a pressure by thresholding using python-vtk

import vtk
filename = "a.foam"

reader = vtk.vtkOpenFOAMReader()
reader.SetFileName(filename)
reader.CreateCellToPointOn()
reader.DecomposePolyhedraOn()
reader.EnableAllCellArrays()
reader.Update()

tArray = vtk_to_numpy(reader.GetTimeValues())
reader.UpdateTimeStep(tArray[-1]) 
reader.Update()

filter_threshold = vtk.vtkThreshold()
filter_threshold.SetInputConnection(reader.GetOutputPort())

how should I select “pressure” on filter class ?

2

I may resolved

import vtk

filename = "case1.foam"
reader = vtk.vtkOpenFOAMReader()
reader.SetFileName(filename)
reader.CreateCellToPointOn()
reader.DecomposePolyhedraOn()
reader.EnableAllCellArrays()
reader.Update()
n_step = reader.GetTimeValues().GetNumberOfValues()
latest_time = reader.GetTimeValues().GetValue(n_step-1)
reader.UpdateTimeStep(latest_time)
reader.Update()

filter_threshold = vtk.vtkThreshold()
filter_threshold.SetInputConnection(reader.GetOutputPort())

#filter_threshold.ThresholdByLower(1)
#filter_threshold.ThresholdByUpper(8700.0)
filter_threshold.ThresholdBetween(0,3600)


#enum FieldAssociations
#  {
#    FIELD_ASSOCIATION_POINTS,
#    FIELD_ASSOCIATION_CELLS,
#    FIELD_ASSOCIATION_NONE,
#    FIELD_ASSOCIATION_POINTS_THEN_CELLS,
#    FIELD_ASSOCIATION_VERTICES,
#    FIELD_ASSOCIATION_EDGES,
#    FIELD_ASSOCIATION_ROWS,
#    NUMBER_OF_ASSOCIATIONS
#  };
FIELD_ASSOCIATION_POINTS = 0
FIELD_ASSOCIATION_CELLS = 1
filter_threshold.SetInputArrayToProcess(0,0,0,FIELD_ASSOCIATION_CELLS ,"p")
filter_threshold.Update()