How to add a custom array to a polydata in paraview?
Question: I know that I can use the Calculator filter for operations on arrays, but I
want to perform some more complicated computations. I managed to do it in
Paraview python shell, but the missing step now is to go back to the viewer
again (or save the new polydata to file). Here is what I have so far:

    
    
    polydata = servermanager.Fetch(FindSource("mydataalreadyopeninparaview"))
    region_size = paraview.vtk.vtkIntArray()
    region_size.SetNumberOfComponents(0)
    region_size.SetName("regionsize")
    for i in range(polydata .GetNumberOfPoints()):
       region_size.InsertNextValue(somecomputedvalue)
    polydata.GetPointData().AddArray(region_size)
    

How can I "import" in the paraview pipeline my newly created data?


Answer: Better approach would be use the **Programmable Filter** to add the array to
your input dataset. In ParaView 4.1, the following script can be added to the
_Script_ on **Properties** panel for the **Programmager Filter**

    
    
    polydata = output
    array = vtk.vtkIntArray()
    array.SetNumberOfComponents(0)
    array.SetName("regionsize")
    for i in range(polydata .GetNumberOfPoints()):
        array.InsertNextValue(somecomputedvalue)
    polydata.GetPointData().AddArray(array);
    

