When I add an SCNLookAtConstraint in ARKit to a node that moves about (when it contains a directional light or a it of geometry) the node becomes invisible. You cannot see the geometry and you cannot see the light coming from it. Exactly the same code in a regualr scenekit simulaiton works fine.
directionalLight = SCNLight()
directionalLight?.type = .directional
lightNode?.light = directionalLight
directionalLight?.castsShadow = true
directionalLight?.shadowColor = UIColor.black
directionalLight?.intensity = defaultLightIntensity
directionalLight?.shadowRadius = 1.2
directionalLight?.zFar = 500
directionalLight?.zNear = 0
directionalLight?.orthographicScale = 10
directionalLight?.shadowSampleCount = 1
directionalLight?.temperature = 5500
directionalLight?.shadowMode = .forward
let constraint = SCNLookAtConstraint(target: virtualObject)
lightNode?.constraints = [constraint]
if I comment out the constraint the light works (but is pointing at the same direction all the time) and I can see the geometry I have added but add the constraint and it's invisible and there's no light.
Is this a bug, do I ahve to work out my own rotations?