SCNView not refreshing but after tap on screen - ios

Question

I am stuck on a problem. I need to apply transformation (scale, rotation, position) right after i add model to my rootNode. Right after when i apply transformation on child model added to rootNode it shows fine on screen but when i apply transformation on rootNode it doesn't refresh. i experimented that as soon i touch screen UI updates. I also tried putting delay of 2,3 secs.
expected
UIView should update as soon i apply transformation to rootNode.
let res = SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 0.5, z: 0, duration: 1))
// let res = SCNAction.sequence([SCNAction.wait(duration: 2000), SCNAction.rotateTo(x: CGFloat(180), y: CGFloat(90), z: CGFloat(0), duration: 1.0)])
self.rootNode.runAction(res)
i tried putting code in
RunLoop.main.perform {}
i tried using
scnView.preferredFramesPerSecond = 30
scnView.rendersContinuously = true
But none works. i am using sdk IOS 13.2. Any help please.
Edit:
var rootNode = SCNNode()
viewDidload(){
scnScene.rootNode.addChildNode(rootNode)
....
}
func initSceneWithModel(modelURL: URL) {
do {
try personModel = addModel(url: modelURL)
menuButton.setImage(UIImage.fontAwesomeIcon(name: .bars, style: .solid, textColor: .white, size: XConstants.FONT_AWSOME_SIZE), for: .normal)
selectedModel = personModel
centerPivot(for: personModel!)
moveNodeToCenter(node: personModel!)
setupEyeBlocker()
// selectedModel = eyeBlocker
updateFieldUI()
DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
self.applyInitTransformations()
}
} catch let error {
Utilities.xalert(inView: self.view, desc: error.localizedDescription)
}
}
func applyInitTransformations() {
if let info = vm.physicialFile.extraInfo {
// personModel?.position = info.person.position
// personModel?.scale = info.person.scale
// personModel?.eulerAngles = info.person.rotation
var valueRotPos = SCNMatrix4Mult(SCNMatrix4MakeRotation(0,0,0,0), SCNMatrix4MakeTranslation(0,0,0))
var valueScale = SCNMatrix4MakeScale(7.0,7.0,7.0) // scales to 0.1 of original size
rootNode.transform = SCNMatrix4Mult(valueRotPos, valueScale)
// rootNode.position = info.root.position
// rootNode.scale = info.root.scale
// rootNode.eulerAngles = info.root.rotation
}
else {
applyEyeBlockerDefaultPosition()
}
}

Answer 1

Apple clearly says:
...
You should not modify the transform property of the root node.
...
(https://developer.apple.com/documentation/scenekit/scnscene/1524029-rootnode)
This might be causing the issues you have with your scene. Avoid SCNActions to be run on the rootNode. They are designed to run on the content of the rootNode (any SCNNode added to the rootNode).
You could probably take a common SCNNode, call it like myRootNode, add it to the real rootNode and add all your other content to myRootNode. Transformations should then apply correctly to all your sub-content, if this is your goal.
BTW: scnView.preferredFramesPerSecond = 30 never gave me more performence or any benefits. Leave it default. Scenekit switches automatically to lower framerates if required.
EDIT:
apply transformation like so:
// Precalculate the Rotation the Position and the Scale
var valueRotPos = SCNMatrix4Mult(SCNMatrix4MakeRotation(0,0,0,0), SCNMatrix4MakeTranslation(0,0,0))
var valueScale = SCNMatrix4MakeScale(0.1,0.1,0.1) // scales to 0.1 of original size
then you do:
myRootNode.transform = SCNMatrix4Mult(valueRotPos, valueScale)
(you could also try to use the worldTransform of the node or the other transform properties of the nodes presentation node-object)