---
title: stretchFactor
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scnparticlesystem/stretchfactor
---

# stretchFactor

A multiplier for stretching particle images along their direction of motion. Animatable.

## Declaration

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

## Discussion

Discussion Use this property to create visual effects that show streaks of motion, such as fireworks. If the orientationMode property value is SCNParticleOrientationMode.free, a non-default stretch factor stretches particle images in the y-axis direction of each particle’s local coordinate space. The default value is 0.0, specifying that particle images maintain their original aspect ratio. You can animate changes to this property’s value. See Animating SceneKit Content.

## See Also

### Specifying Particle Appearance

- [particleSize](scenekit/scnparticlesystem/particlesize.md)
- [particleSizeVariation](scenekit/scnparticlesystem/particlesizevariation.md)
- [particleColor](scenekit/scnparticlesystem/particlecolor.md)
- [particleColorVariation](scenekit/scnparticlesystem/particlecolorvariation.md)
- [particleImage](scenekit/scnparticlesystem/particleimage.md)
- [fresnelExponent](scenekit/scnparticlesystem/fresnelexponent.md)