---
title: life
framework: scenekit
role: symbol
role_heading: Type Property
path: scenekit/scnparticlesystem/particleproperty/life
---

# life

The remaining time in the particle’s life span, in seconds.

## Declaration

```swift
static let life: SCNParticleSystem.ParticleProperty
```

## Discussion

Discussion This property’s value is a floating-point scalar (an NSNumber object for particle property controllers, or a single float value for particle event or modifier blocks). SceneKit initializes this value using the particle system’s particleLifeSpan and particleLifeSpanVariation properties, then decreases the value when rendering each frame. When the life value reaches 0.0, the particle dies (that is, SceneKit no longer simulates or renders it). Particle property controllers can use this property’s value as an input, but not change it.

## See Also

### Type Properties

- [angle](scenekit/scnparticlesystem/particleproperty/angle.md)
- [angularVelocity](scenekit/scnparticlesystem/particleproperty/angularvelocity.md)
- [bounce](scenekit/scnparticlesystem/particleproperty/bounce.md)
- [charge](scenekit/scnparticlesystem/particleproperty/charge.md)
- [color](scenekit/scnparticlesystem/particleproperty/color.md)
- [contactNormal](scenekit/scnparticlesystem/particleproperty/contactnormal.md)
- [contactPoint](scenekit/scnparticlesystem/particleproperty/contactpoint.md)
- [frame](scenekit/scnparticlesystem/particleproperty/frame.md)
- [frameRate](scenekit/scnparticlesystem/particleproperty/framerate.md)
- [friction](scenekit/scnparticlesystem/particleproperty/friction.md)
- [opacity](scenekit/scnparticlesystem/particleproperty/opacity.md)
- [position](scenekit/scnparticlesystem/particleproperty/position.md)
- [rotationAxis](scenekit/scnparticlesystem/particleproperty/rotationaxis.md)
- [size](scenekit/scnparticlesystem/particleproperty/size.md)
- [velocity](scenekit/scnparticlesystem/particleproperty/velocity.md)