SCNQuaternion
A representation of a quaternion.
Declaration
typealias SCNQuaternion = SCNVector4Discussion
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 SCNVector4 structure.
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.