# streamlines from custom source, via programmable filter

**URL:** https://discourse.paraview.org/t/streamlines-from-custom-source-via-programmable-filter/9920
**Category:** ParaView Support
**Created:** [June 27, 2022, 1:10pm UTC](https://discourse.paraview.org/t/streamlines-from-custom-source-via-programmable-filter/9920 "2022-06-27T13:10:46Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![\_Marco](https://discourse.paraview.org/user_avatar/discourse.paraview.org/_marco/32/5242_2.png) [@\_Marco](https://discourse.paraview.org/u/_Marco)
#### Post date: [June 27, 2022, 1:10pm UTC](https://discourse.paraview.org/t/streamlines-from-custom-source-via-programmable-filter/9920/1 "2022-06-27T13:10:46Z")

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Dear all,

I am using PV 5.10.1, on Linux.

I am trying to draw streamlines, **from a non standard source** , for wind field. I would appreciate some help or suggestions, as I am failing to persuade PV to actually draw the lines along with terrain (and other data).

With “non standard source”, I mean that the 3 vector components (u,v,w, here named ua, va, omega) are given as **separate scalar variables** (time, level, lon, lat). Their properties are:

 ![Properties](https://discourse.paraview.org/uploads/default/original/2X/3/371342b1f9ab69a6534bdfed687091be21a40678.png)

So far, and also in the attempt to individually manipulate each component separately, I have used a programmable filter to extract those 3 components:

![Filter](https://discourse.paraview.org/uploads/default/original/2X/c/cf7f542feef955bee6a088dc2ac8a307885c3a0c.png)

My data come from a numerical model, the results of which I am regrinding (separately, outside PV) and importing to do nice-looking visualization.

Question:  
Now, in the workflow described above, what is the syntax to have streamlines appearing in my animation? How can I achieve drawing streamlines, i.e. what data type should my separate components be, to be plotted and visualized?

Remarks:  
I tried “playing around” with the available test datasets (the cylinder and its flow) and I see that velocity (“v”) has all the components ‘nested’ inside the same variable. That might depend, I suspect, from the variable type (I think I have understood it must be a polymesh?)

And also: once my first goal is achieved, can I animate using SURFACE-LIC to have a tracer-like particle moving along the streamline(s)?

Thank you so much for any comment or suggestion you might want to share with me.  
Marco

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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: [June 29, 2022, 7:10am UTC](https://discourse.paraview.org/t/streamlines-from-custom-source-via-programmable-filter/9920/2 "2022-06-29T07:10:20Z")

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HI @_Marco

You do not need a prog filter for that. A calculator with this expression should be enough:

`ua*iHat+va*jHat+omega*kHat`.

Then you will be able to use the SurfaceLIC and the StreamTracer without issues.