# Value change: Euler to Quaternion then back to Euler

**URL:** <https://forum.babylonjs.com/t/value-change-euler-to-quaternion-then-back-to-euler/23254>\
**Category:** Questions\
**Created:** [August 21, 2021, 4:24am UTC](https://forum.babylonjs.com/t/value-change-euler-to-quaternion-then-back-to-euler/23254 "2021-08-21T04:24:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Kuangzheng\_Xia](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/kuangzheng_xia/32/17495_2.png) [@Kuangzheng\_Xia](https://forum.babylonjs.com/u/Kuangzheng_Xia)\
**Post date:** [August 21, 2021, 4:24am UTC](https://forum.babylonjs.com/t/value-change-euler-to-quaternion-then-back-to-euler/23254/1 "2021-08-21T04:24:28Z")

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[https://playground.babylonjs.com/#1ST43U#665](https://playground.babylonjs.com/#1ST43U#665)  
I have an `euler` rotation. After I modify it, I translate `euler` into `yprQuaternion2`, then I translate `yprQuaternion2` into `euler2`. Why `euler` and `euler2` has different value?

```auto
    var euler = box.rotationQuaternion.toEulerAngles()
    console.log(euler)
    euler.x *= -1 
    euler.y += Math.PI*(180/180)
    euler.y += 2*(Math.PI-euler.y)
    euler.z = 0
    var yprQuaternion2 = BABYLON.Quaternion.RotationYawPitchRoll(euler.y, euler.x, euler.z);
    var euler2 = yprQuaternion2.toEulerAngles()
    console.log([euler.x,euler.y,euler.z])
    console.log(euler2)

```

![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/7/1/71e709033053e0aded7c005165dfe331b78df3ad.png) Three `console.log` give three different output. What happens lol

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<div class="post-metadata">

**Author:** ![slin](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/slin/32/36084_2.png) [@slin](https://forum.babylonjs.com/u/slin)\
**Post date:** [August 21, 2021, 2:39pm UTC](https://forum.babylonjs.com/t/value-change-euler-to-quaternion-then-back-to-euler/23254/2 "2021-08-21T14:39:26Z")

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In the 2nd and the 3rd logs, euler and euler2 are probably the same angle but presented differently in values.

4.886921905584122 / (Math.PI \* 2) \* 360 = 280 degree.  
-1.396263401595464 / (Math.PI \* 2) \* 360 = -80 degree.