Instance Property

birthRateVariation

The range of randomized particle birth rate values. Animatable.

Declaration

@property(nonatomic) CGFloat birthRateVariation;

Discussion

Setting a nonzero value for this property randomizes the effect of the birthRate property. For each emission period, SceneKit randomly adjusts the birth rate by up to half the birthRateVariation value. For example, if the birthRate value is 100 particles and the birthRateVariation value is 50 particles, the system randomly emits between 75 and 125 particles during its emissionDuration period.

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.

emissionDurationVariation

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