A representation of a quaternion.
- iOS 8.0+
- macOS 10.10+
- tvOS 9.0+
- watchOS 3.0+
A quaternion is a mathematical construct useful for describing rotations in three-dimensional space. Although its implementation differs from that of a 4-component vector, you specify a quaternion value using the same fields as an
SceneKit uses unit quaternions (those whose components satisfy the equation
x*x + y*y + z*z + w*w == 1) for the
orientation property of nodes.