Adding a SCNBillboardConstraint makes the node dissapear - ios

Question

After what I've read in the documentation and on the internet a SCNBillboardConstraint would rotate a node to always face the pointOfView node - in the case of ARKit, the user's camera.
The thing is, when I add a SCNBillboardConstraint to a child node, it dissapears. The nodes are just some SCNTexts added as a subchild of a more complex model.
The hierarchy looks something like this: RootNode - > Text node (two of them).
Just after I added the root node to the scene's root node, I add this constraint in the following way:
updateQueue.async {
self.sceneView.scene.rootNode.addChildNode(virtualObject)
self.sceneView.addOrUpdateAnchor(for: virtualObject)
self.addBillboardContraintsToText(object: virtualObject)
}
func addBillboardContraintsToText(object: VirtualObject) {
guard let storeNode = object.childNodes.first else {
return
}
for node in storeNode.childNodes {
if let geometry = node.geometry, geometry.isKind(of: SCNText.self) {
let billboard = SCNBillboardConstraint()
node.constraints = [billboard]
}
}
}
The text nodes have their position set properly relative to their root node, so there's no problem with that. When I add a SCNLookAtConstraint though, it works just fine.
node.pivot = SCNMatrix4Rotate(node.pivot, Float.pi, 0, 1, 0)
let lookAt = SCNLookAtConstraint(target: sceneView.pointOfView)
lookAt.isGimbalLockEnabled = true
node.constraints = [lookAt]
Any ideas why the SCNBillboardConstraint might not work? Am I doing something wrong?

Answer 1

This Code (with apples CupScn) works just fine for me:
cupNode.position = SCNVector3(0.5,0,-0.5)
guard let virtualObjectScene = SCNScene(named: "cup.scn", inDirectory: "Models.scnassets/cup") else {
return
}
let wrapperNode = SCNNode()
for child in virtualObjectScene.rootNode.childNodes {
child.geometry?.firstMaterial?.lightingModel = .physicallyBased
wrapperNode.addChildNode(child)
}
cupNode.addChildNode(wrapperNode)
scene.rootNode.addChildNode(cupNode)
let billboardConstraint = SCNBillboardConstraint()
billboardConstraint.freeAxes = SCNBillboardAxis.Y
cupNode.constraints = [billboardConstraint]