# PhysicsViewer working only with MeshImposter

**URL:** <https://forum.babylonjs.com/t/physicsviewer-working-only-with-meshimposter/29654>\
**Category:** Questions\
**Tags:** mesh, viewer, physics\
**Created:** [April 24, 2022, 2:10pm UTC](https://forum.babylonjs.com/t/physicsviewer-working-only-with-meshimposter/29654 "2022-04-24T14:10:10Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![DjDjalilo](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/djdjalilo/32/23073_2.png) [@DjDjalilo](https://forum.babylonjs.com/u/DjDjalilo)\
**Post date:** [April 24, 2022, 2:10pm UTC](https://forum.babylonjs.com/t/physicsviewer-working-only-with-meshimposter/29654/1 "2022-04-24T14:10:10Z")

</div>

Hi everyone,

([here a playground for the example](https://playground.babylonjs.com/#WIR77Z#1317))

I was wondering why my physicsViewer isn’t working when i use this line :

```auto
sphere.physicsImpostor = new BABYLON.PhysicsImpostor(sphere, BABYLON.PhysicsImpostor.SphereImpostor, { mass: 0 }, scene);

```

having this result :  
 ![Screenshot_14](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/d/0/d02a2a96faee2243f4833870cc7400a27e5fd5cf.png)

but when i use this :

```auto
sphere.physicsImpostor = new BABYLON.PhysicsImpostor(sphere, BABYLON.PhysicsImpostor.MeshImpostor, { mass: 0 }, scene);

```

I have this result :

 ![Screenshot_15](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/0/9/09898ae4bfd45f05c0a5fd534fe59977e74a78f1.png)

I’m sure it’s something really stupid, but i didn’t figure out why 😕 .

Thanks everyone !

---

<div class="post-metadata">

**Author:** ![carolhmj](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/carolhmj/32/25918_2.png) [@carolhmj](https://forum.babylonjs.com/u/carolhmj)\
**Post date:** [April 25, 2022, 3:57pm UTC](https://forum.babylonjs.com/t/physicsviewer-working-only-with-meshimposter/29654/2 "2022-04-25T15:57:55Z")

</div>

Hey there! Thank you for this example, this was actually a bug in the OimoJS plugin 🙂 PR is up with a fix: [[Physics] Fix OimoJS plugin syncMeshWithImpostor method. by carolhmj · Pull Request #12442 · BabylonJS/Babylon.js (github.com)](https://github.com/BabylonJS/Babylon.js/pull/12442)

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<div class="post-metadata">

**Author:** ![carolhmj](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/carolhmj/32/25918_2.png) [@carolhmj](https://forum.babylonjs.com/u/carolhmj)\
**Post date:** [April 25, 2022, 3:59pm UTC](https://forum.babylonjs.com/t/physicsviewer-working-only-with-meshimposter/29654/3 "2022-04-25T15:59:10Z")

</div>

Ah, and just as a PS, I saw you’re setting `mesh.alpha` in your example, but that won’t work as alpha is a property of the material, not the mesh 🙂 if you want to set alpha, you’ll have to create a material for that mesh and set the alpha there