# Create and visualize streamline of velocity field

**URL:** https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436
**Category:** ParaView Support
**Created:** [March 10, 2019, 5:04pm UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436 "2019-03-10T17:04:16Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![drudox00](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@drudox00](https://discourse.paraview.org/u/drudox00)
#### Post date: [March 10, 2019, 5:04pm UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436/1 "2019-03-10T17:04:16Z")

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Hi everybody !  
I have the follow object :

- a 3d cube velocity magnitude and velocity vector field (\*.vtr format)
- a 3d polydata (\*.vtk) set of point (representing polymer smaller than one cell of the previous cube)

I would like to create the stream line of velocity around the polymer , which is the correct procedure to compute it ??

this is my situations : (I used a very large sphere to represent the polydata (respect to the polymer))!

 ![polymer_domain](https://discourse.paraview.org/uploads/default/original/2X/b/b12e38c4dc032a1215b645c5081f46c90f39b8d4.png)

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### Author: ![drudox00](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@drudox00](https://discourse.paraview.org/u/drudox00)
#### Post date: [March 10, 2019, 5:08pm UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436/2 "2019-03-10T17:08:33Z")

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I would have a small subset in which I see the streamline of velocity field surrounding polymer

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### 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: [March 11, 2019, 9:36am UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436/3 "2019-03-11T09:36:50Z")

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Did you try the stream tracer ?

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### Author: ![drudox00](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/d/a5b964/32.png) [@drudox00](https://discourse.paraview.org/u/drudox00)
#### Post date: [March 11, 2019, 9:54am UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436/4 "2019-03-11T09:54:56Z")

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Yes I tried ! but if I select the vtr imported object the stream tracer is not available as filter !  
this is th reason why I’m asking for the correct procedure … if for example I create a probe locator from the main object then the stream tracer is clickable (available) but I would like to use the filter “stream tracer from custom area” in order to create stream tracer from the centre of poly\_data representing the polymer ! May you help me about ?

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### 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: [March 11, 2019, 9:58am UTC](https://discourse.paraview.org/t/create-and-visualize-streamline-of-velocity-field/1436/5 "2019-03-11T09:58:25Z")

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The following should work:

- Open Both of your files
- Click on the 3d velocity cube
- Add a “Stream Tracer with Custom Source” Filter
- In the input dialog, select your polydata as the “Source”
- Configure the Stream Tracer according to your needs, Apply