---
title: particleLifeSpanVariation
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scnparticlesystem/particlelifespanvariation
---

# particleLifeSpanVariation

The range, in seconds, of randomized particle life spans. Animatable.

## Declaration

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

## Discussion

Discussion Setting a nonzero value for this property randomizes the effect of the particleLifeSpan property. SceneKit randomly adjusts the life span of each particle by up to half the particleLifeSpanVariation value. For example, if the particleLifeSpan value is 1.0 seconds and the particleLifeSpanVariation value is 0.5 seconds, each particle appears for a random duration between 0.75 and 1.25 seconds before being removed from the scene. The default value is 0.0 seconds, specifying no randomization. You can animate changes to this property’s value. See Animating SceneKit Content.

## See Also

### Managing Particle Motion

- [particleAngle](scenekit/scnparticlesystem/particleangle.md)
- [particleAngleVariation](scenekit/scnparticlesystem/particleanglevariation.md)
- [particleVelocity](scenekit/scnparticlesystem/particlevelocity.md)
- [particleVelocityVariation](scenekit/scnparticlesystem/particlevelocityvariation.md)
- [particleAngularVelocity](scenekit/scnparticlesystem/particleangularvelocity.md)
- [particleAngularVelocityVariation](scenekit/scnparticlesystem/particleangularvelocityvariation.md)
- [particleLifeSpan](scenekit/scnparticlesystem/particlelifespan.md)