PhysicsWorld The cloned world.
Creates a new PhysicsWorld that is a copy of this world, including all of its PhysicsBody, PhysicsShape and PhysicsJoint.
The clone is a separate world, so handles you hold for this world do not resolve against it; enumerate the clone with PhysicsWorld.GetBodies and similar. The clone is not owned and its PhysicsWorld.userData is not copied; callback options come across but any callback targets must be set on the clone.