title: Scenekit: Animating Camera Node While Using Constraints
body: <p>I am attempting to animate the camera node in Scenekit while having the camera look at a specific point with a constraint. For some reason activating the constraint locks the camera position.
  Is there a specific reason this does not work or what am I missing here?</p>
  
  <pre><code>cameraNode = SCNNode()
  let camera = SCNCamera()
  cameraNode.camera = camera
  cameraNode.position = SCNVector3Make(5.0, 10.0, 5.0)
  
  scene.rootNode.addChildNode(cameraNode)
  
  let center = SCNNode()
  center.position = SCNVector3Make(0, 0, 0)
  let lookConstraint = SCNLookAtConstraint(target: center)
  cameraNode.constraints = [lookConstraint]        
  
  let firstAnimation = SCNAction.move(to: SCNVector3Make(10, 10, 10), duration: 2.0)
  let secondAnimation = SCNAction.move(by: SCNVector3Make(0, 5, 5), duration: 2.0)
  let sequence = SCNAction.sequence([firstAnimation, secondAnimation])
  
  cameraNode.runAction(sequence)
  </code></pre>