acceleration
The constant acceleration vector, in units per second per second, applied to all particles in the system. Animatable.
Declaration
var acceleration: SCNVector3 { get set }Discussion
Use this property to simulate effects such as wind or gravity on particles.
To use the same gravity vector that applies to physics bodies in the scene, or to apply more than one constant acceleration to particles, see the isAffectedByGravity property.
The default value is SCNVector3Zero, specifying no acceleration.
You can animate changes to this property’s value. See Animating SceneKit Content.