Instance Property


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


var birthRate: CGFloat { get set }


The system emits this number of particles at a constant rate through the duration of the period specified by the emissionDuration property. A value of zero prevents the system from emitting particles, unless you randomize the birth rate with the birthRateVariation property.

The default value is 1.

You can animate changes to this property’s value. See Animating SceneKit Content.

See Also

Managing Particle Emission Timing

var emissionDuration: CGFloat

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

var emissionDurationVariation: CGFloat

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

var idleDuration: CGFloat

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

var idleDurationVariation: CGFloat

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

var loops: Bool

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

var warmupDuration: CGFloat

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

var birthRateVariation: CGFloat

The range of randomized particle birth rate values. Animatable.