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# particleBounceVariation

The range of randomized restitution coefficients for particles. Animatable.

```
var particleBounceVariation: CGFloat { get set }
```

## Discussion

Setting a nonzero value for this property randomizes the effect of the [`particleBounce`](/documentation/SceneKit/SCNParticleSystem/particleBounce) property. SceneKit randomly adjusts the restitution coefficient of each particle by up to half the [`particleBounceVariation`](/documentation/SceneKit/SCNParticleSystem/particleBounceVariation) value. For example, if the [`particleBounce`](/documentation/SceneKit/SCNParticleSystem/particleBounce) value is `1.0` and the [`particleBounceVariation`](/documentation/SceneKit/SCNParticleSystem/particleBounceVariation) value is `0.5`, each particle uses a random restitution coefficient between `0.75` and `1.25` for physics simulation.

The default value is `0.0`, specifying no randomization.

You can animate changes to this property’s value. See [Animating SceneKit Content](/documentation/SceneKit/animating-scenekit-content).

---

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