---
title: fogDensityExponent
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scnscene/fogdensityexponent
---

# fogDensityExponent

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

## Declaration

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

## Discussion

Discussion A fog effect fades out the contents of the scene with increasing distance from the pointOfView location, replacing them with increasing intensities of the fogColor color. The 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.

## See Also

### Adding Fog to a Scene

- [fogStartDistance](scenekit/scnscene/fogstartdistance.md)
- [fogEndDistance](scenekit/scnscene/fogenddistance.md)
- [fogColor](scenekit/scnscene/fogcolor.md)