# Inplane Streamlines Dean Vortices Error
**URL:** https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443
**Category:** ParaView Support
**Created:** [February 16, 2026, 9:54am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443 "2026-02-16T09:54:20Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@kodaiApran](https://discourse.paraview.org/u/kodaiApran)
#### Post date: [February 16, 2026, 9:54am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/1 "2026-02-16T09:54:20Z")
Hello ParaView Community,
I am trying to visualize in-plane streamlines on a cross-sectional slice of a pipe in ParaView, but I keep running into errors regardless of the filter pipeline I use.
My Setup is OpenFOAM-13 / Build: 13-cde978a97c9
My goal is to create streamlines from a simple s-bended pipe on a 2D Slice (Y-Z plane) to visualize vortices/secondary flow.
Like here:
[Source: [Dean vortices in turbulent flows: rocking or rolling? | Journal of Visualization | Springer Nature Link](https://link.springer.com/article/10.1007/s12650-011-0108-8) ]
My current pipeline:
1. Slice (Normal: 1 0 0, Origin: inside the pipe)
2. Surface Vectors (Select Input Vectors: U, Constraint Mode: Parallel)
3. Cell Data to Point Data (to ensure point data for the tracer)
4. Stream Tracer (Vectors: U, Seed Type: Line or Cloud I tried both which failed)
The error which results is: ERR| vtkPStreamTracer: Bad velocity array.
I think my velocity array is falsely defined. But I cant get it to work.
Thanks in advance for your help!
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 16, 2026, 9:57am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/2 "2026-02-16T09:57:36Z")
Please share your data.
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### Author:  [@kodaiApran](https://discourse.paraview.org/u/kodaiApran)
#### Post date: [February 16, 2026, 10:06am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/3 "2026-02-16T10:06:02Z")
> [@I want to share data here, how can I do that ?](https://discourse.paraview.org/t/i-want-to-share-data-here-how-can-i-do-that/5296/1):
>
> arrow button in the editor
[realGasTube.zip](https://discourse.paraview.org/uploads/short-url/gQhfihOufJvN3BrX9KCbjmJTqEC.zip) (3.5 MB)
In this zip there is the .cgns file. 🙂
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 16, 2026, 10:50am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/4 "2026-02-16T10:50:49Z")
like that ?
[stream.pvsm](https://discourse.paraview.org/uploads/short-url/dpynkMuEjyXjn6uAjN3aPW3ww76.pvsm) (643.9 KB)
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### Author:  [@kodaiApran](https://discourse.paraview.org/u/kodaiApran)
#### Post date: [February 16, 2026, 11:16am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/5 "2026-02-16T11:16:15Z")
Thanks a lot (especially for the fast answer),
How can I adjust the density/resolution of the lines. I know there is a field in the normal StreamTracer Filter, but I cant find it with the CustomSource StreamTracer or ConvertToPointCloud Filter. And is there a possibility to recreate also the arrows with the corresponding direction.
I tried to recreate it (without state file), but it doesnt work. Is there any special setting for ConverttoPointCloud or StreamTracerwithCustomSource (Input=Slice1 and Seed=ConvertToPointCloud1)
🙂
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 16, 2026, 11:18am UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/6 "2026-02-16T11:18:47Z")
> [@kodaiApran](#):
>
> How can I adjust the density/resolution of the lines.
By reducing the number of seed, you can use MaskPoints for that.
> is there a possibility to recreate also the arrows with the corresponding direction.
Add a Glyph filter.
> Is there any special setting for ConverttoPointCloud or StreamTracerwithCustomSource (Input=Slice1 and Seed=ConvertToPointCloud1)
Nothing special, you can send your state file here if you want me to take a look.
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### Author:  [@kodaiApran](https://discourse.paraview.org/u/kodaiApran)
#### Post date: [February 17, 2026, 1:03pm UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/7 "2026-02-17T13:03:52Z")
> [@mwestphal](#):
>
> Nothing special, you can send your state file here if you want me to take a look.
Thanks!
Maskpoints works in your state file.
But I cant get it to work with the same procedure as shown in your file. Is there any flattening of vectors?
My state .pvsm is attached
[stream\_dean\_vortex.pvsm](https://discourse.paraview.org/uploads/short-url/w37ud6dD95TqDqp4Bl87zlNCdf6.pvsm) (555.1 KB)
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 17, 2026, 1:07pm UTC](https://discourse.paraview.org/t/inplane-streamlines-dean-vortices-error/17443/8 "2026-02-17T13:07:29Z")
Your state file is corrupted but I was able to identify that you need to enable “Surface Streamlines” on the stream tracer.