creating multiblock data from a datafile with a programmable source

ParaView Support
1

My starting point is this example for reading a simple hex mesh:
https://www.paraview.org/Wiki/ParaView/Simple_ParaView_3_Python_Filters#Producing_An_Unstructured_Grid_(Source)

I would like to do something similar for a multiblock mesh, for example this same hex mesh but one of the edges is an additional block. I don’t know how to change this code to tell paraview that output should be 2 blocks. Does somebody have an example on how to read and create a simple multiblock mesh ?

2

I found a multiblock example that can be used to create a programmable source for a multiblock here (this website was not popping up in my google searcher earlier):
https://kitware.github.io/vtk-examples/site/Python/CompositeData/MultiBlockDataSet/

To get it to work in a programmable source I just copied the first part:

    from paraview import vtk
    import os
    from vtkmodules.vtkCommonDataModel import vtkMultiBlockDataSet
    from vtkmodules.vtkFiltersSources import vtkSphereSource

    # PART 1 Make some Data.
    # Make a tree.
    root = vtkMultiBlockDataSet()

    branch = vtkMultiBlockDataSet()
    root.SetBlock(0, branch)

    # Make some leaves.
    leaf1 = vtkSphereSource()
    leaf1.SetCenter(0, 0, 0)
    leaf1.Update()
    branch.SetBlock(0, leaf1.GetOutput())

    leaf2 = vtkSphereSource()
    leaf2.SetCenter(1.75, 2.5, 0)
    leaf2.SetRadius(1.5)
    leaf2.Update()
    branch.SetBlock(1, leaf2.GetOutput())

    leaf3 = vtkSphereSource()
    leaf3.SetCenter(4, 0, 0)
    leaf3.SetRadius(2)
    leaf3.Update()
    root.SetBlock(1, leaf3.GetOutput())

    output.DeepCopy(root)
3

A follow-up question is: how can I set the names of the branches and leaves (that appears in the data hierarchy) ?

4

It is possible to specify a name for the Meta Data of each branch or leaf as shown below.

branch.GetMetaData(0).Set(vtk.vtkCompositeDataSet.NAME(), 'sphere1')
branch.GetMetaData(1).Set(vtk.vtkCompositeDataSet.NAME(), 'sphere2')
root.GetMetaData(1).Set(vtk.vtkCompositeDataSet.NAME(), 'sphere3')
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