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# imageSequenceInitialFrameVariation

The range of randomized initial frames for particle image animation. Animatable.

```
var imageSequenceInitialFrameVariation: CGFloat { get set }
```

## Discussion

Setting a nonzero value for this property randomizes the effect of the [`imageSequenceInitialFrame`](/documentation/SceneKit/SCNParticleSystem/imageSequenceInitialFrame) property. SceneKit randomly adjusts the initial animation frame for each particle by up to half the [`imageSequenceInitialFrameVariation`](/documentation/SceneKit/SCNParticleSystem/imageSequenceInitialFrameVariation) value. For example, if the [`imageSequenceInitialFrame`](/documentation/SceneKit/SCNParticleSystem/imageSequenceInitialFrame) value is `10.0` and the [`imageSequenceInitialFrameVariation`](/documentation/SceneKit/SCNParticleSystem/imageSequenceInitialFrameVariation) value is `5.0`, each particle randomly begins on a frame between frame 7.5 and frame 12.5 of the image sequence animation.

When you use image sequences for particles, SceneKit interpolates between frames of animation, so a fractional value (either for this property or for either endpoint of the range it determines) results in a partial fade between two animation frames.

The default value is `0.0` seconds, specifying no randomization.

You can animate changes to this property’s value. See [Animating SceneKit Content](/documentation/SceneKit/animating-scenekit-content).

---

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