# Visualise the normal vector

**URL:** https://community.freefem.org/t/visualise-the-normal-vector/779
**Category:** General Discussion
**Created:** [January 30, 2021, 10:17pm UTC](https://community.freefem.org/t/visualise-the-normal-vector/779 "2021-01-30T22:17:54Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![yongxing](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/yongxing/32/3632_2.png) [@yongxing](https://community.freefem.org/u/yongxing)
#### Post date: [January 30, 2021, 10:17pm UTC](https://community.freefem.org/t/visualise-the-normal-vector/779/1 "2021-01-30T22:17:54Z")

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Please can someone let me know how to visualise the normal vector at the boundary (or an interior interface) of a domain?

Thanks in advance!

YX

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### Author: ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)
#### Post date: [January 31, 2021, 2:10pm UTC](https://community.freefem.org/t/visualise-the-normal-vector/779/2 "2021-01-31T14:10:11Z")

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Sorry no simple way, but you can do some think like

[plot-normals.edp](https://community.freefem.org/uploads/short-url/ngD3UgSiHUiDNcnwl8Z1qrhLjdX.edp) (348 Bytes) !

the normals of a carre mesh:

[plot-normal.edp|593x500](https://community.freefem.org/uploads/short-url/AnH7QwYsaz1IzAcyRlpoVJTEJPf.jpeg)

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### Author: ![yongxing](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/yongxing/32/3632_2.png) [@yongxing](https://community.freefem.org/u/yongxing)
#### Post date: [February 3, 2021, 10:20pm UTC](https://community.freefem.org/t/visualise-the-normal-vector/779/3 "2021-02-03T22:20:00Z")

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It works perfectly! Thank you very much.  
Yongxing.