# Does paraview filter automatically update its properties?
**URL:** https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020
**Category:** Development
**Created:** [July 29, 2025, 11:37am UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020 "2025-07-29T11:37:57Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Northern\_Condor](https://discourse.paraview.org/u/Northern_Condor)
#### Post date: [July 29, 2025, 11:37am UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020/1 "2025-07-29T11:37:57Z")
Hello!
Lets say I have a filter, with properties “a” and “b”, both ints
And for some values of “a”, “b” is fixed and set by filter.
For example, for a = 1, b is always 5
So, if i write from Python:
And then
f.a = 1 (here filter should define b itself, and )
f.b should be set to 5,
but will it be seen in filter before f.UpdatePropertyInformation() is explicitly called?
Are there any ways to make these updates automatically by specifying some commands in XML?
Thank you very much
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### Author:  [@nenad-vujicic](https://discourse.paraview.org/u/nenad-vujicic)
#### Post date: [July 31, 2025, 12:11pm UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020/2 "2025-07-31T12:11:29Z")
If I understood correctly the sources, to achieve this, you need to
1. Implement RequestInformation() routine with updating logic (where b is updated depending on a)
2. Specify some hints (if supported) in .xml to notify to update b’s GUI when a changes
3. Call UpdatePropertyInformation ..
I hope it helps. Please, double-check.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [August 4, 2025, 12:34pm UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020/3 "2025-08-04T12:34:27Z")
> [@Northern\_Condor](#):
>
> Are there any ways to make these updates automatically by specifying some commands in XML?
No, `b` should not be property. Or you can have a logic in your code to take `b` into account only if `a` is not 1.
@nenad-vujicic please avoid repeating incorrect answers.
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### Author:  [@nenad-vujicic](https://discourse.paraview.org/u/nenad-vujicic)
#### Post date: [August 4, 2025, 12:53pm UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020/4 "2025-08-04T12:53:29Z")
I sincerely apologize for giving incorrect answers. It was not intentional.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [August 4, 2025, 12:55pm UTC](https://discourse.paraview.org/t/does-paraview-filter-automatically-update-its-properties/17020/5 "2025-08-04T12:55:02Z")
No worries, thanks for the feedback 🙂