Realitykit - Custom Material

Question

Using Realitykit, trying to change the material of moon Entity to a custom .jpg and then tapping the screen to spawn that object based off hitTest. Nothing shows up when I tap and getting the following error in debug: [Collision] Bad paramater (SphereRadius), value = 0.000000, passed to shape creation.

import UIKit
import RealityKit

class ViewController: UIViewController {

    @IBOutlet var arView: ARView!

    override func viewDidLoad() {
        super.viewDidLoad()

    }

        override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
            if let touchLocation = touches.first?.location(in: arView){
                let hitTest = arView.hitTest(touchLocation)
                if let hitResult = hitTest.first {
                    addObject(at: hitResult)
                }
            }
        }

        func addObject(at hitResult: CollisionCastHit) {
            let moonAnchor = try! Galaxy.loadWorld()
            let moon = moonAnchor.moon! as! ModelEntity
            var material = SimpleMaterial()
            material.baseColor = try! MaterialColorParameter.texture(TextureResource.load(named: "8k_moon.jpg"))
            moon.model?.materials = [material]
            moon.position = SIMD3(x: hitResult.position.x, y: hitResult.position.y, z: hitResult.position.z)
            arView.scene.addAnchor(moonAnchor)
        }

}

Answer 1

I have encountered that error when trying to hitTest an entity without a CollisionComponent. Hit testing requires a CollisionComponent on target entities:

"The method ignores entities that lack a CollisionComponent." https://developer.apple.com/documentation/realitykit/arview/3243230-hittest

If this is the problem, and since your model is being loaded from Reality Composer, a solution would be to check the "Participates" box in the Physics section of RC.