Type Method

vortex()

Creates a field whose forces circulate around an axis.

Declaration

class func vortex() -> SCNPhysicsField

Return Value

A physics field object. To use the field in a scene, attach it to the physicsField property of an SCNNode object.

Discussion

The force on an object in a vortex field is tangential to the line from the object’s position to the field’s axis and proportional to the object’s mass. (The field’s axis is a line that is parallel to its direction vector and that passes through its center. For details, see the offset property.) For example, when a vortex field’s area of effect contains many objects, the resulting scene resembles a tornado: The objects simultaneously revolve around and fly away from the field’s center.

By default, a vortex circulates counterclockwise relative to its direction vector. To make it circulate clockwise, set the field’s strength property to a negative value.

The default falloffExponent value for a vortex field is 0.0, indicating that the field’s effect is constant throughout its area of effect.

See Also

Creating Physics Fields

class func drag() -> SCNPhysicsField

Creates a field that slows any object in its area of effect with a force proportional to the object’s velocity.

class func radialGravity() -> SCNPhysicsField

Creates a field that accelerates objects toward its center.

class func linearGravity() -> SCNPhysicsField

Creates a field that accelerates objects in a specific direction.

class func noiseField(smoothness: CGFloat, animationSpeed: CGFloat) -> SCNPhysicsField

Creates a field that applies random forces to objects in its area of effect.

class func turbulenceField(smoothness: CGFloat, animationSpeed: CGFloat) -> SCNPhysicsField

Creates a field that applies random forces to objects in its area of effect, with magnitudes proportional to those objects’ velocities.

class func spring() -> SCNPhysicsField

Creates a field that pulls objects toward its center with a spring-like force.

class func electric() -> SCNPhysicsField

Creates a field that attracts or repels objects based on their electrical charge and on their distance from the field’s center.

class func magnetic() -> SCNPhysicsField

Creates a field that attracts or repels objects based on their electrical charge, velocity, and distance from the field’s axis.