HitTest prints AR Entity name even when I am not tapping on it

Question

My Experience.rcproject has animations that can be triggered by tap action. Two cylinders are named “Button 1” and “Button 2” and have Collide turned on.

Answer 1

To implement a robust Hit-Testing in RealityKit, all you need is the following code:

import RealityKit

class ViewController: UIViewController {

    @IBOutlet var arView: ARView!
    let scene = try! Experience.loadScene()

    @IBAction func onTap(_ sender: UITapGestureRecognizer) {

        let tapLocation: CGPoint = sender.location(in: arView)
        let result: [CollisionCastHit] = arView.hitTest(tapLocation)

        guard let hitTest: CollisionCastHit = result.first
        else { return }

        let entity: Entity = hitTest.entity
        print(entity.name)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        scene.steelBox!.scale = [2,2,2]
        scene.steelCylinder!.scale = [2,2,2]

        scene.steelBox!.name = "BOX"
        scene.steelCylinder!.name = "CYLINDER"

        arView.scene.anchors.append(scene)
    }
}

When you tap on entities in ARView a Debug Area prints "BOX" or "CYLINDER". And if you tap anything but entities, a Debug Area prints just "Ground Plane".

If you need to implement a Ray-Casting read this post, please.

P.S.

In case you run this app on macOS Simulator, it prints just Ground Plane instead of BOX and CYLINDER. So you need to run this app on iPhone.