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# fogDensityExponent

The transition curve for the fog’s intensity between its start and end distances. Animatable.

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

## Discussion

A fog effect fades out the contents of the scene with increasing distance from the [`pointOfView`](/documentation/SceneKit/SCNSceneRenderer/pointOfView) location, replacing them with increasing intensities of the [`fogColor`](/documentation/SceneKit/SCNScene/fogColor) color. The [`fogDensityExponent`](/documentation/SceneKit/SCNScene/fogDensityExponent) property determines the smoothness or abruptness of this transition.

A value of `0.0` (the default) specifies no attenuation—the fog’s intensity is the same at all distances . A value of `1.0` specifies a linear transition, and a value of `2.0` specifies a quadratic transition curve. Higher values have little visible effect.

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

---

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