# How to calculate the normal of a 3D surface mesh

**URL:** <https://community.freefem.org/t/how-to-calculate-the-normal-of-a-3d-surface-mesh/1955>\
**Category:** General Discussion\
**Created:** [August 23, 2022, 6:34pm UTC](https://community.freefem.org/t/how-to-calculate-the-normal-of-a-3d-surface-mesh/1955 "2022-08-23T18:34:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![zcwang6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zcwang6/32/371_2.png) [@zcwang6](https://community.freefem.org/u/zcwang6)\
**Post date:** [August 23, 2022, 6:34pm UTC](https://community.freefem.org/t/how-to-calculate-the-normal-of-a-3d-surface-mesh/1955/1 "2022-08-23T18:34:53Z")

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Dear Freefem team, is there any way we can calculate the normal of the surface mesh? I also attached the files here. thank you so much.  
[9T\_MOTOR\_R.mesh](https://community.freefem.org/uploads/short-url/pr3WrZwrHBfKnucvBT3SWtr3k5E.mesh) (229.0 KB)

 ![surfacemesh](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/6/6bca28e722ff69facfb9ddfcf2914d02d24da68a.png)  
[surface\_mesh.edp](https://community.freefem.org/uploads/short-url/ibaMdSCgiAZe9Bnusjrad6crkUJ.edp) (216 Bytes)