# Vorticity expressed as a scalar field when using the ParticleTracer filter

**URL:** https://discourse.paraview.org/t/vorticity-expressed-as-a-scalar-field-when-using-the-particletracer-filter/15465
**Category:** ParaView Support
**Created:** [September 27, 2024, 2:16pm UTC](https://discourse.paraview.org/t/vorticity-expressed-as-a-scalar-field-when-using-the-particletracer-filter/15465 "2024-09-27T14:16:23Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![mgarreau](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/m/53a042/32.png) [@mgarreau](https://discourse.paraview.org/u/mgarreau)
#### Post date: [September 27, 2024, 2:16pm UTC](https://discourse.paraview.org/t/vorticity-expressed-as-a-scalar-field-when-using-the-particletracer-filter/15465/1 "2024-09-27T14:16:23Z")

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Hi,  
I am using the ParticleTracer filter which has a “Compute Vorticity” option. I was wondering why the generated vorticity field is a scalar and not a vector field. Does this vorticity correspond to the projection of the vorticity along the selected input vectors (e.g. velocity) or is it the magnitude of the vorticity?  
Thanks in advance,