# Question on Programmable Filter using vtkPythonAlgorithmBase
**URL:** https://discourse.paraview.org/t/question-on-programmable-filter-using-vtkpythonalgorithmbase/16495
**Category:** ParaView Support
**Tags:** python, vtk
**Created:** [April 17, 2025, 7:43am UTC](https://discourse.paraview.org/t/question-on-programmable-filter-using-vtkpythonalgorithmbase/16495 "2025-04-17T07:43:22Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Oracle\_0](https://discourse.paraview.org/u/Oracle_0)
#### Post date: [April 17, 2025, 7:43am UTC](https://discourse.paraview.org/t/question-on-programmable-filter-using-vtkpythonalgorithmbase/16495/1 "2025-04-17T07:43:22Z")
Hi, I have read many post from others earlier and it helped me a lot. I have a question that probably hasn’t asked earlier.
I am using separate python script using vtkPythonAlgorithmBase and loading it through Manage Plugins menu, then using it as a filter on my dataset.
Within script, I am creating vtkStreamTracer and getting it’s output, storing it in vtkPolyData object. It’s works perfectly.
I have couple of questions:
1. How do I change ‘Display’ properties such as LineWidth of the output object in Paraview pipeline from script only? I have tried using functions from paraview.simple within RequestData() function of the script. Unfortunately it goes into infinite recursion where RequestData() calls itself, probably because some functions updates/accesses pipeline objects. I have made a macro to style my Stream Lines after I apply this filter. But I want it to be done within one step: creation of final output Stream Lines and styling of it.
2. Is some of the functions aren’t available in vtkPythonAlgorithm? Like vtkProgrammableFilter is available but not vtkPythonProgrammableFilter.
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### Author:  [@nicolas.vuaille](https://discourse.paraview.org/u/nicolas.vuaille)
#### Post date: [April 17, 2025, 12:34pm UTC](https://discourse.paraview.org/t/question-on-programmable-filter-using-vtkpythonalgorithmbase/16495/2 "2025-04-17T12:34:26Z")
You cannot modify the visualization from _inside_ a filter:
- a plugin defines the filter contents
- a macro _uses_ the filter and defines the display.
To have a one-step workflow, you can have a macro that creates your filter and configures its display.
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### Author:  [@Oracle\_0](https://discourse.paraview.org/u/Oracle_0)
#### Post date: [April 18, 2025, 2:25am UTC](https://discourse.paraview.org/t/question-on-programmable-filter-using-vtkpythonalgorithmbase/16495/3 "2025-04-18T02:25:29Z")
Oh, I see. Thanks.