Instance Property


The initial speed, in units per second, for newly spawned particles. Animatable.


@property(nonatomic) CGFloat particleVelocity;


Particles begin moving at this speed in the direction determined by the birthDirection or emittingDirection property. Their directions and speeds may change thereafter according to the acceleration property or physics effects (see the affectedByGravity, affectedByPhysicsFields, and colliderNodes properties). You can randomize the speed of newly spawned particles with the particleAngularVelocityVariation property.

Particle speed is measured in units (of the local coordinate space containing the particle system) per second.

The default value is 0.0 units per second, specifying that newly emitted particles are stationary until otherwise influenced.

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

See Also

Managing Particle Motion


The rotation angle, in degrees, of newly spawned particles. Animatable.


The range, in degrees of randomized initial particle angles. Animatable.


The range, in units per second, of randomized initial particle speeds. Animatable.


The initial spin rate, in degrees per second, of newly spawned particles. Animatable.


The range, in degrees per second, of randomized initial angular velocities for particles. Animatable.


The duration, in seconds, for which each particle is rendered before being removed from the scene. Animatable.


The range, in seconds, of randomized particle life spans. Animatable.