# 2D velocity streamlines, filters unavailable

**URL:** https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313
**Category:** ParaView Support
**Created:** [January 10, 2020, 11:04pm UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313 "2020-01-10T23:04:59Z")
**Posts on this page:** 6
**Page:** 1

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### Author: ![msjuhasznora](https://discourse.paraview.org/user_avatar/discourse.paraview.org/msjuhasznora/32/3221_2.png) [@msjuhasznora](https://discourse.paraview.org/u/msjuhasznora)
#### Post date: [January 10, 2020, 11:04pm UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/1 "2020-01-10T23:04:59Z")

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Hi,

I have a 2D velocity vector and I would like to visualise the streamlines. As you can see on the attached image, all the filters are greyed out, including the little buttons in the third line. Could someone tell me why all filters are unavailable at this point?

 ![Screen Shot 2020-01-10 at 23.59.46](https://discourse.paraview.org/uploads/default/original/2X/c/c3b970be825f2040c46e18979e3c7436ad9a9476.jpeg)

Thank you so much for any help,  
Nora

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### Author: ![wascott](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/w/8e8cbc/32.png) [@wascott](https://discourse.paraview.org/u/wascott)
#### Post date: [January 11, 2020, 12:14am UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/2 "2020-01-11T00:14:49Z")

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Could you post a dataset?

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### Author: ![msjuhasznora](https://discourse.paraview.org/user_avatar/discourse.paraview.org/msjuhasznora/32/3221_2.png) [@msjuhasznora](https://discourse.paraview.org/u/msjuhasznora)
#### Post date: [January 11, 2020, 8:12am UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/3 "2020-01-11T08:12:28Z")

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A velocity pvd file:

[velocity\_anis\_degree2\_eps\_1.0\_nr\_cells\_1800.pvd](https://discourse.paraview.org/uploads/short-url/a1ZmIISDP4iwfeB6I1EMC6fX0Xx.pvd) (205 Bytes)

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### Author: ![Kenneth\_Moreland](https://discourse.paraview.org/user_avatar/discourse.paraview.org/kenneth_moreland/32/15033_2.png) [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [January 11, 2020, 5:56pm UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/4 "2020-01-11T17:56:42Z")

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I haven’t look at the data set, but it sounds like the problem is that you have 2D vectors and the streamline filter is expecting 3D vectors. You can fix the problem using the `Calculator` filter to convert the 2D vector to the 3D vector. Simply set the `Expression` of the calculator to something like `velocity_X*iHat+velocity_Y*jHat` (where `velocity` is replaced with whatever name your 2D velocity field has).

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### Author: ![msjuhasznora](https://discourse.paraview.org/user_avatar/discourse.paraview.org/msjuhasznora/32/3221_2.png) [@msjuhasznora](https://discourse.paraview.org/u/msjuhasznora)
#### Post date: [January 11, 2020, 10:47pm UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/5 "2020-01-11T22:47:20Z")

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Thank you for your idea. I don’t know what I am doing wrong, but all filters are greyed out (as shown at my first post in this topic). So I can not use the Calculator filter to make the the 2D data into 3D, as the Calculator filter is unavailable as well.

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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: [January 12, 2020, 5:12am UTC](https://discourse.paraview.org/t/2d-velocity-streamlines-filters-unavailable/3313/6 "2020-01-12T05:12:20Z")

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You have to press the “Apply” button.