Instance Property

birthDirection

The possible initial directions for newly spawned particles, relative to the emitter shape.

Declaration

@property(nonatomic) SCNParticleBirthDirection birthDirection;

Discussion

This property defines initial directions for new particles relative to the geometry specified in the emitterShape property. This property has no effect if the emitterShape property value is nil.

For example, if the emitter shape is an SCNSphere geometry and the birth location is SCNParticleBirthDirectionSurfaceNormal, new particles radiate away from the center of the sphere. You can randomize the direction of newly spawned particles with the spreadingAngle property.

The default value is SCNParticleBirthDirectionConstant, specifying that all particles use the same base emittingDirection value. For possible values, see SCNParticleBirthDirection.

See Also

Managing Particle Emission Locations

emitterShape

The shape of the region of space where the system spawns new particles.

birthLocation

The possible locations for newly spawned particles, relative to the emitter shape.

SCNParticleBirthLocation

Options for the initial location of each emitted particle, used by the birthLocation property.

SCNParticleBirthDirection

Options for the initial direction of each emitted particle, used by the birthDirection property.

emittingDirection

The initial direction for newly spawned particles. Animatable.

spreadingAngle

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