Why is ARKit with SceneKit SCNNode orientation not changing? [duplicate] - ios

Question

So, I was able to put a box node at the anchors position.
Now, how do I rotate the SCNNode in the scene?
I am trying to modify the node's transform & eulerAngles, but they have no effect:
func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {
print("nodeFor anchor \(anchor)")
guard anchor.name == "card" else { return nil }
let colors = [
UIColor.yellow, // front
UIColor.red, // right
UIColor.blue, // back
UIColor.green, // left
UIColor.purple, // top
UIColor.gray] // bottom
let sideMaterials = colors.map { color -> SCNMaterial in
let material = SCNMaterial()
material.diffuse.contents = color
material.locksAmbientWithDiffuse = true
return material
}
let boxGeometry = SCNBox(width: 0.12, height: 0.01, length: 0.07, chamferRadius: 0)
boxGeometry.materials = sideMaterials
let node = SCNNode(geometry: boxGeometry)
node.transform = SCNMatrix4MakeRotation(-Float.pi / 2, 1, 0, 0)
node.eulerAngles.x = .pi / 2
return node
}
I also tried to do the rotation in func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor)
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
node.eulerAngles.x = .pi / 2
}
But that didn't help as well.
I was successful in animating rotation with code below.
let spin = CABasicAnimation(keyPath: "rotation")
// Use from-to to explicitly make a full rotation around z
spin.fromValue = NSValue(scnVector4: SCNVector4(x: 0, y: 0, z: 1, w: 0))
spin.toValue = NSValue(scnVector4: SCNVector4(x: 0, y: 0, z: 1, w: Float(2 * Double.pi)))
spin.duration = 3
spin.repeatCount = 1
node.addAnimation(spin, forKey: "rotation")
Based on that success, I also tried (but failed)
node.rotation = SCNVector4(x: 5, y: 4, z: 3, w: 0)
Does anybody have a clue how I can rotate my node in the delegate methods of ARSCNViewDelegate ?

Answer 1

The ARSession will position and orientate the node you vend to it. It's best to perform rotations on a child node to the one that is vended. So in func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode?
Prior to returning, you could say:
let node = SCNNode(geometry: boxGeometry)
node.eulerAngles = SCNVector3(x: -Float.pi / 2, y: 0, z: 0)
let rootNode = SCNNode()
rootNode.addChildNode(node)
return rootNode