[vtkusers] Help with vtkOpenFOAMReader and extraction

[Sandro Grm]

Dear,
        
        I started to use vtk (python interface) last week. I was not
        able to
        find any example how work with vtkOpenFOAMReader. I'm able to
        obtain
        vtkMultiBlockDataSet, next I extract a block which is of
        vtkUnstructuredGrid type, but from there I was not able to
        extract
        single data set, for example scalar (pressure "p"), or vector
        (velocity
        "U")  to render or anyhow other manipulate those data.
        
        Please can someone give me a hint how to do it.
        
        Thanks + Best, Sandro. 
        
        My python code is:
        
        # -*- coding: utf-8 -*-
        import os
        import vtk as vtk
        import numpy as np
        import scipy as sp
        import math
        
        rootDir = "thermoViscoPlasticFoam"
        fileName = rootDir + "/system/controlDict"
        
        reader = vtk.vtkOpenFOAMReader()
        reader.SetFileName(fileName)
        reader.CreateCellToPointOn()
        reader.DecomposePolyhedraOn()
        reader.Update()
        
        # this print is listed at the bottom
        print str(reader.GetOutput())
        
        # extract first time interval data set
        ug = reader.GetOutput().GetBlock(0)
        
        # saw in same examples, but do not understand the point
        compositeFilter = vtk.vtkCompositeDataGeometryFilter()
        compositeFilter.SetInputConnection(reader.GetOutputPort())
        compositeFilter.Update()
        
        # here is my question, how to see which data set is inside and 
        # how to extract them for further use (render, cut plain, ...)
        
        # mapper
        mapper = vtk.vtkPolyDataMapper()
        mapper.SetInputConnection(compositeFilter.GetOutputPort())
        
        # plot to screen
        actor = vtk.vtkActor()
        actor.SetMapper(mapper)
        
        renderer = vtk.vtkRenderer()
        renderer.AddActor(actor)
        
        renWin = vtk.vtkRenderWindow()
        renWin.AddRenderer(renderer)
        
        iren = vtk.vtkRenderWindowInteractor();
        iren.SetRenderWindow(renWin);
        
        renWin.SetSize(850, 850)
        renWin.Render()
        iren.Start();
        
        
        What I get for output has nothing to do with reality. 
        
        
        
        And the reader.GetOutput print:
        
        vtkMultiBlockDataSet (0x18f5310)
          Debug: Off
          Modified Time: 396
          Reference Count: 2
          Registered Events: (none)
          Source: (none)
          Information: 0x18ec270
          Data Released: False
          Global Release Data: Off
          UpdateTime: 403
          Release Data: Off
          UpdateExtent: Not Initialized
          Update Number Of Pieces: 1
          Update Piece: 0
          Update Ghost Level: 0
          MaximumNumberOfPieces: -1
          RequestExactExtent: Off
           Field Data:
            Debug: Off
            Modified Time: 152
            Reference Count: 1
            Registered Events: (none)
            Number Of Arrays: 1
            Array 0 name = CasePath
            Number Of Components: 1
            Number Of Tuples: 24
          Number Of Children: 1
          Child 0: vtkUnstructuredGrid
            Debug: Off
            Modified Time: 390
            Reference Count: 2
            Registered Events: (none)
            Source: (none)
            Information: 0x1a330a0
            Data Released: False
            Global Release Data: Off
            UpdateTime: 0
            Field Data:
              Debug: Off
              Modified Time: 174
              Reference Count: 1
              Registered Events: (none)
              Number Of Arrays: 0
              Number Of Components: 0
              Number Of Tuples: 0
            Number Of Points: 25586
            Number Of Cells: 24800
            Cell Data:
              Debug: Off
              Modified Time: 374
              Reference Count: 1
              Registered Events: (none)
              Number Of Arrays: 6
              Array 0 name = Sr
              Array 1 name = T
              Array 2 name = U
              Array 3 name = magGradU
              Array 4 name = nu
              Array 5 name = p
              Number Of Components: 8
              Number Of Tuples: 24800
              Copy Tuple Flags: ( 1 1 1 1 1 0 1 1 )
              Interpolate Flags: ( 1 1 1 1 1 0 0 1 )
              Pass Through Flags: ( 1 1 1 1 1 1 1 1 )
              Scalars: 
                Debug: Off
                Modified Time: 371
                Reference Count: 1
                Registered Events: (none)
                Name: p
                Data type: float
                Size: 24800
                MaxId: 24799
                NumberOfComponents: 1
                Information: 0
                Name: p
                Number Of Components: 1
                Number Of Tuples: 24800
                Size: 24800
                MaxId: 24799
                LookupTable: (none)
                Array: 0x1eb0c40
              Vectors: 
                Debug: Off
                Modified Time: 296
                Reference Count: 1
                Registered Events: (none)
                Name: U
                Data type: float
                Size: 74400
                MaxId: 74399
                NumberOfComponents: 3
                Information: 0
                Name: U
                Number Of Components: 3
                Number Of Tuples: 24800
                Size: 74400
                MaxId: 74399
                LookupTable: (none)
                Array: 0x1debef0
              Normals: (none)
              TCoords: (none)
              Tensors: (none)
              GlobalIds: (none)
              PedigreeIds: (none)
              EdgeFlag: (none)
            Point Data:
              Debug: Off
              Modified Time: 390
              Reference Count: 1
              Registered Events: (none)
              Number Of Arrays: 6
              Array 0 name = Sr
              Array 1 name = T
              Array 2 name = U
              Array 3 name = magGradU
              Array 4 name = nu
              Array 5 name = p
              Number Of Components: 8
              Number Of Tuples: 25586
              Copy Tuple Flags: ( 1 1 1 1 1 0 1 1 )
              Interpolate Flags: ( 1 1 1 1 1 0 0 1 )
              Pass Through Flags: ( 1 1 1 1 1 1 1 1 )
              Scalars: 
                Debug: Off
                Modified Time: 387
                Reference Count: 1
                Registered Events: (none)
                Name: p
                Data type: float
                Size: 25586
                MaxId: 25585
                NumberOfComponents: 1
                Information: 0
                Name: p
                Number Of Components: 1
                Number Of Tuples: 25586
                Size: 25586
                MaxId: 25585
                LookupTable: (none)
                Array: 0x1ec8fd0
              Vectors: 
                Debug: Off
                Modified Time: 322
                Reference Count: 1
                Registered Events: (none)
                Name: U
                Data type: float
                Size: 76758
                MaxId: 76757
                NumberOfComponents: 3
                Information: 0
                Name: U
                Number Of Components: 3
                Number Of Tuples: 25586
                Size: 76758
                MaxId: 76757
                LookupTable: (none)
                Array: 0x1e34980
              Normals: (none)
              TCoords: (none)
              Tensors: (none)
              GlobalIds: (none)
              PedigreeIds: (none)
              EdgeFlag: (none)
            Bounds: 
              Xmin,Xmax: (0, 0.61)
              Ymin,Ymax: (0, 0.29)
              Zmin,Zmax: (-0.0101496, 0.0151496)
            Compute Time: 421
            Number Of Points: 25586
            Point Coordinates: 0x17cae20
            Locator: 0
            Number Of Pieces: 1
            Piece: -1
            Ghost Level: 0