Instance Property

emissionDurationVariation

The range, in seconds, of randomized emission duration values. Animatable.

Declaration

@property(nonatomic) CGFloat emissionDurationVariation;

Discussion

Setting a nonzero value for this property randomizes the effect of the emissionDuration property. For each emission period, SceneKit randomly adjusts the duration by up to half the emissionDurationVariation value. For example, if the emissionDuration value is 1.0 seconds and the emissionDurationVariation value is 0.5 seconds, the system emits particles over a period of 0.75 to 1.25 seconds before stopping.

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 Emission Timing

emissionDuration

The duration, in seconds, over which the system spawns new particles. Animatable.

idleDuration

The duration, in seconds, of periods when the system emits no particles. Animatable.

idleDurationVariation

The range, in seconds, of randomized idle duration values. Animatable.

loops

A Boolean value that determines whether the system repeats its emission and idle periods.

warmupDuration

The duration, in seconds, for which particles are spawned before the system is first rendered. Animatable.

birthRate

The number of particles spawned during each emission period. Animatable.

birthRateVariation

The range of randomized particle birth rate values. Animatable.