Решил вопрос. Может кому-то будет полезно:
> // create and add a camera to the scene
> let cameraNode = SCNNode()
> cameraNode.camera = SCNCamera()
> let cameraRoot = SCNNode()
> cameraNode.position = SCNVector3(x: 0, y: 10, z: 20)
> cameraRoot.addChildNode(cameraNode)
> scene.rootNode.addChildNode(cameraRoot)
// setup a target object
let sphere = SCNSphere(radius: 0)
let sphereNode = SCNNode(geometry: sphere)
scene.rootNode.addChildNode(sphereNode)
// put a constraint on the camera
let targetNode = SCNLookAtConstraint(target: sphereNode)
targetNode.isGimbalLockEnabled = true
cameraNode.constraints = [targetNode]