# What is needed in a vtk file for streamtracer to work?

**URL:** https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080
**Category:** ParaView Support
**Created:** [August 1, 2022, 2:33pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080 "2022-08-01T14:33:47Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![LizardKing](https://discourse.paraview.org/user_avatar/discourse.paraview.org/lizardking/32/9683_2.png) [@LizardKing](https://discourse.paraview.org/u/LizardKing)
#### Post date: [August 1, 2022, 2:33pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080/1 "2022-08-01T14:33:47Z")

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Hi

I am generating vtk files in the following format:

# vtk DataFile Version 2.0

Unstructured grid legacy vtk file  
ASCII

DATASET POLYDATA  
POINTS 2622 float  
0.0280 0.0000 0.7495  
…  
POINT\_DATA 2622  
VECTORS V float  
0.0000 0.0009 0.0000  
…

The data represents fluid flow velocity at fixed points in a sphere.

Glyphs work and show the flow but the streamtracer shows absolutely nothing.

Does my vtk file format need to be different?

Cheers in advance

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### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [August 1, 2022, 3:12pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080/2 "2022-08-01T15:12:33Z")

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Does your file include cells ?

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<div class="post-metadata">

### Author: ![LizardKing](https://discourse.paraview.org/user_avatar/discourse.paraview.org/lizardking/32/9683_2.png) [@LizardKing](https://discourse.paraview.org/u/LizardKing)
#### Post date: [August 1, 2022, 3:28pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080/3 "2022-08-01T15:28:53Z")

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No cells. Are cells needed for the streamtracer to work?

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### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [August 1, 2022, 3:31pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080/4 "2022-08-01T15:31:48Z")

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Yes ! They are used during the integration step. See [here](https://vtk.org/doc/nightly/html/classvtkStreamTracer.html#details) for more technical details about how the filter works.

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### Author: ![Sciencegeek](https://discourse.paraview.org/user_avatar/discourse.paraview.org/sciencegeek/32/1609_2.png) [@Sciencegeek](https://discourse.paraview.org/u/Sciencegeek)
#### Post date: [August 5, 2022, 12:00pm UTC](https://discourse.paraview.org/t/what-is-needed-in-a-vtk-file-for-streamtracer-to-work/10080/5 "2022-08-05T12:00:58Z")

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Thanks Fellas,  
I needed that information also…  
Bob