---
title: screenSpaceAmbientOcclusionBias
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scncamera/screenspaceambientocclusionbias
---

# screenSpaceAmbientOcclusionBias

An offset for modulating ambient occlusion effects.

## Declaration

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

## Discussion

Discussion Ambient occlusion is an effect that improves material shading by calculating the amounts of ambient light that reach various parts of a surface, creating shadows on parts of a geometry where incoming light is obscured by other parts of the geometry. (You can provide pre-rendered ambient occlusion effects for a material using its ambientOcclusion property.) Screen-space ambient occlusion (SSAO) provides a real-time approximation of this effect for the entire scene viewed through the camera. This screenSpaceAmbientOcclusionBias value is used in an intermediate stage of calculating the SSAO effect, and measures a distance in scene units. Increasing or decreasing this value from its default of 0.03 can help to offset unrealistic effects produced by changing other SSAO settings.

## See Also

### Adding Screen-Space Ambient Occlusion

- [screenSpaceAmbientOcclusionIntensity](scenekit/scncamera/screenspaceambientocclusionintensity.md)
- [screenSpaceAmbientOcclusionRadius](scenekit/scncamera/screenspaceambientocclusionradius.md)
- [screenSpaceAmbientOcclusionDepthThreshold](scenekit/scncamera/screenspaceambientocclusiondepththreshold.md)
- [screenSpaceAmbientOcclusionNormalThreshold](scenekit/scncamera/screenspaceambientocclusionnormalthreshold.md)