# Cesium.Matrix4.multiply

**URL:** <https://community.cesium.com/t/cesium-matrix4-multiply/7891>\
**Category:** CesiumJS\
**Created:** [January 13, 2019, 5:44pm UTC](https://community.cesium.com/t/cesium-matrix4-multiply/7891 "2019-01-13T17:44:37Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Dorian\_Tourin-Lebret](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Dorian\_Tourin-Lebret](https://community.cesium.com/u/Dorian_Tourin-Lebret)\
**Post date:** [January 13, 2019, 5:44pm UTC](https://community.cesium.com/t/cesium-matrix4-multiply/7891/1 "2019-01-13T17:44:37Z")

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Hi,

Using Cesium 1.50 with Chrome 71, I get an error trying to compute:

Cesium.Matrix4.multiply(Cesium.Matrix4.IDENTITY, Cesium.Matrix4.IDENTITY);

message: "Expected result to be typeof object, actual typeof was undefined"  
name: "DeveloperError"  
stack: "Error  
&nbsp;&nbsp;&nbsp;&nbsp;at new DeveloperError ([http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:540:19](http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:540:19))  
&nbsp;&nbsp;&nbsp;&nbsp;at Object.Check.typeOf.object ([http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:1866:19](http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:1866:19))  
&nbsp;&nbsp;&nbsp;&nbsp;at Function.Matrix4.multiply ([http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:13530:22](http://127.0.0.1/cesium/Cesium-1.50/Build/Cesium/Cesium.js:13530:22))  
&nbsp;&nbsp;&nbsp;&nbsp;at \<anonymous\>:1:16"

That should not occur, right?

That's a simple case before trying to rotate a 3D model by implementing [https://groups.google.com/forum/#!topic/cesium-dev/Yv49L4K2xeo](https://groups.google.com/forum/#!topic/cesium-dev/Yv49L4K2xeo)

Thanks,

Dorian.

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<div class="post-metadata">

**Author:** ![Scott\_Reynolds](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/scott_reynolds/32/2014_2.png) [@Scott\_Reynolds](https://community.cesium.com/u/Scott_Reynolds)\
**Post date:** [January 14, 2019, 12:46pm UTC](https://community.cesium.com/t/cesium-matrix4-multiply/7891/2 "2019-01-14T12:46:00Z")

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Hi Dorian,

You are missing the third parameter, result, which is required.

Scott

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<div class="post-metadata">

**Author:** ![Dorian\_Tourin-Lebret](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Dorian\_Tourin-Lebret](https://community.cesium.com/u/Dorian_Tourin-Lebret)\
**Post date:** [January 14, 2019, 5:12pm UTC](https://community.cesium.com/t/cesium-matrix4-multiply/7891/3 "2019-01-14T17:12:27Z")

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Thank you!