RealityKit ARkit：从光线投射中找到一个锚点（或实体） - 始终为零

Question

当我触摸屏幕时，我使用光线投射将对象（实体和锚点）放置到它的 worldTransform

然后我尝试触摸这个对象以获得它的锚点（或者它自己的实体）

我正在尝试使用 raycast（或 hitTest）找到以前放置的锚点，但每件事 returns nil

像那样:

这是我的 onTap 代码：

@IBAction func onTap(_ sender: UITapGestureRecognizer){
   let tapLocation = sender.location(in: arView)
        
   guard let result = arView.raycast(from: tapLocation, allowing: .estimatedPlane, alignment: .any).first else { return }
  print("we have anchor??")
  print(result.anchor) // always nil
        
  // never hit
  if let existResult = arView.hitTest(tapLocation).first {
     print("hit test trigger")
     if let entity = existResult.entity as Entity? {
        NSLog("we have an entity \(entity.name)")
...
      } 
   }  
}

这就是我创建对象和锚点的方式：

let anchor = AnchorEntity(world: position)
anchor.addChild(myObj)
arView.scene.anchors.append(anchor)
// my obj is now visible

你知道为什么我摸不到锚点吗？

编辑：

ARview配置：


        arView.session.delegate = self
        arView.automaticallyConfigureSession = true

        let config = ARWorldTrackingConfiguration()
        config.planeDetection = [.horizontal, .vertical]
        
        NSLog("FINISHED INIT")
        
        if ARWorldTrackingConfiguration.supportsSceneReconstruction(.mesh) {
            config.sceneReconstruction = .mesh // .meshWithClassification
            arView.environment.sceneUnderstanding.options.insert([.occlusion])

            arView.debugOptions.insert(.showSceneUnderstanding)
            NSLog("FINISHED with scene reco")
        } else {
            NSLog("no not support scene Reconstruction")
        }
        

        
        let tapGesture = UITapGestureRecognizer(target: self, action:#selector(onTap))
        
        arView.addGestureRecognizer(tapGesture)
        arView.session.run(config)

Answer 1

只有在 ARKit 检测到平面后才能进行光线投射。它只能对平面或特征点进行光线投射。因此，请确保您运行具有平面检测的 AR 配置（垂直或水平取决于您的情况）

let configuration = ARWorldTrackingConfiguration()
configuration.planeDetection = .horizontal

可以在renderer didAdd delegate of ARSCNViewDelegate中查看是否添加了plane anchor

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
     
if let planeAnchor = anchor as? ARPlaneAnchor {
   //plane detected
  }
}

Answer 2

我终于设法找到了解决方案：

我的ModelEntity（锚定）必须有一个碰撞形状！

所以简单地添加后 entity.generateCollisionShapes(recursive: true).

这就是我生成简单框的方式：


    let box: MeshResource = .generateBox(width: width, height: height, depth: length)
    var material = SimpleMaterial()
    material.tintColor = color
    let entity = ModelEntity(mesh: box, materials: [material])
    entity.generateCollisionShapes(recursive: true) // Very important to active collisstion and hittesting !
    return entity

所以之后我们必须告诉 arView 听手势 :

arView.installGestures(.all, for: entity)

最后：


    @IBAction func onTap(_ sender: UITapGestureRecognizer){
        let tapLocation = sender.location(in: arView)

        if let hitEntity = arView.entity(
            at: tapLocation
        ) {
            print("touched")
            print(hitEntity.name)
            // touched !

            return ;
        }

    }

RealityKit ARkit：从光线投射中找到一个锚点（或实体） - 始终为零

RealityKit ARkit : find an anchor (or entity) from raycast - always nil

swift

arkit

realitykit