# How to Calculate the tangent Plane of a Point on a 3D Tile Model

**URL:** <https://community.cesium.com/t/how-to-calculate-the-tangent-plane-of-a-point-on-a-3d-tile-model/26172>\
**Category:** CesiumJS\
**Created:** [August 17, 2023, 5:08am UTC](https://community.cesium.com/t/how-to-calculate-the-tangent-plane-of-a-point-on-a-3d-tile-model/26172 "2023-08-17T05:08:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![renyuhai](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/renyuhai/32/15534_2.png) [@renyuhai](https://community.cesium.com/u/renyuhai)\
**Post date:** [August 17, 2023, 5:08am UTC](https://community.cesium.com/t/how-to-calculate-the-tangent-plane-of-a-point-on-a-3d-tile-model/26172/1 "2023-08-17T05:08:35Z")

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Hello everyone, I have a question to ask. I want to know how to calculate the tangent plane of the point selected by the mouse when passing through the 3DTile model. Just like the effect in the picture below, but I cannot find a method to obtain the normal vector or triangular patch. Does anyone know how to implement it? Please guide me.

 ![b7833c22008e52c374f95223deaa49d](https://global.discourse-cdn.com/cesium/original/2X/d/dfdbfaf9fe9396cb8a363336ebeb23cc34c06a2a.png)