# Preserve pathlines after particle is deleted
**URL:** https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141
**Category:** ParaView Support
**Created:** [October 8, 2021, 7:46am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141 "2021-10-08T07:46:48Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Veljko\_Lapcevic](https://discourse.paraview.org/u/Veljko_Lapcevic)
#### Post date: [October 8, 2021, 7:46am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/1 "2021-10-08T07:46:49Z")
Hi there,
I am using Temporal Particles To Pathlines filter to analyze particle trajectories over time.
In one of simulations particle number is changed due to nature of simulation, this means those particles are deleted at certain locations and pathlines disappear in next time step.
My question is simple, is there any workaround to preserve pathline after particle is deleted?
I am using sequence of .vtu files and any existing topic is not giving any hint on solution of this problem.
Regards
Veljko
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 8, 2021, 7:53am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/2 "2021-10-08T07:53:59Z")
> [@Veljko\_Lapcevic](#):
>
> is there any workaround to preserve pathline after particle is deleted?
You may want to add a correct particle id in your simulation so that ParaView can track them.
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### Author:  [@Veljko\_Lapcevic](https://discourse.paraview.org/u/Veljko_Lapcevic)
#### Post date: [October 8, 2021, 7:56am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/3 "2021-10-08T07:56:31Z")
Thank you for suggestion.
Can this be done by Generate Ids or Generate Global Ids?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 8, 2021, 7:59am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/4 "2021-10-08T07:59:19Z")
No, ParaView cannot guess that, you need to compute that before ParaView.
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### Author:  [@Veljko\_Lapcevic](https://discourse.paraview.org/u/Veljko_Lapcevic)
#### Post date: [October 8, 2021, 8:03am UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/5 "2021-10-08T08:03:54Z")
Good, I have particle ids in my input and pathline is drawn correctly until particle is deleted. Then, pathline disappears as well.
My goal is to preserve all pathlines when I reach final timestep, regardless of particles.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 8, 2021, 12:09pm UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/6 "2021-10-08T12:09:30Z")
I’m afraid there is no such option in the TemporalParticleToPathLine, but you could add a particle that is not moving instead of having your particle disapear.
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### Author:  [@Veljko\_Lapcevic](https://discourse.paraview.org/u/Veljko_Lapcevic)
#### Post date: [October 8, 2021, 12:25pm UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/7 "2021-10-08T12:25:10Z")
Can I do it in paraView?
Or I need to adjust my simulation?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 8, 2021, 12:37pm UTC](https://discourse.paraview.org/t/preserve-pathlines-after-particle-is-deleted/8141/8 "2021-10-08T12:37:46Z")
Much easier in simulation I think