# \[LagrangianParticleTracker\] Faster locator for vtkimage data

**URL:** https://discourse.paraview.org/t/lagrangianparticletracker-faster-locator-for-vtkimage-data/6192
**Category:** ParaView Support
**Created:** [January 9, 2021, 10:51pm UTC](https://discourse.paraview.org/t/lagrangianparticletracker-faster-locator-for-vtkimage-data/6192 "2021-01-09T22:51:03Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![BinWang0213](https://discourse.paraview.org/user_avatar/discourse.paraview.org/binwang0213/32/5674_2.png) [@BinWang0213](https://discourse.paraview.org/u/BinWang0213)
#### Post date: [January 9, 2021, 10:51pm UTC](https://discourse.paraview.org/t/lagrangianparticletracker-faster-locator-for-vtkimage-data/6192/1 "2021-01-09T22:51:03Z")

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Hey all,

I’d like to trace particles in an image-based velocity field (1000x500x500). Now everything works well but it is too slow to trace even 10k particles in such dataset. I found the following code may help to speed up the process.

[https://gitlab.kitware.com/vtk/vtk/-/blob/2f1976cc6585643f62fc13ed42cbfd9b13b15c25/Filters/FlowPaths/vtkLagrangianBasicIntegrationModel.cxx#L1218](https://gitlab.kitware.com/vtk/vtk/-/blob/2f1976cc6585643f62fc13ed42cbfd9b13b15c25/Filters/FlowPaths/vtkLagrangianBasicIntegrationModel.cxx#L1218)

But how can I select such fast cartesian grid locator in Paraview?

Thanks,  
Bin

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<div class="post-metadata">

### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [January 11, 2021, 9:10am UTC](https://discourse.paraview.org/t/lagrangianparticletracker-faster-locator-for-vtkimage-data/6192/2 "2021-01-11T09:10:13Z")

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> [@BinWang0213](#):
>
> image-based velocity field

You already are using it if you input data is a vtkImageData.