ARKit – 沿特定轴（不在平面上）拖动节点

我试图将一个节点正好拖到我的手指在Y轴上的屏幕上。 但我找不到任何办法，这是我目前的代码。 你有什么主意吗？

 var movedObject:SCNNode? @objc func handlePan(_ recognizer: UIPanGestureRecognizer) { if recognizer.state == .began { let tapPoint: CGPoint = recognizer.location(in: sceneView) let result = sceneView.hitTest(tapPoint, options: nil) if result.count == 0 { return } let hitResult: SCNHitTestResult? = result.first movedObject = hitResult?.node //.parent?.parent } else if recognizer.state == .changed { if (movedObject != nil) { let tapPoint: CGPoint = recognizer.location(in: sceneView) let hitResults = sceneView.hitTest(tapPoint, types: .featurePoint) let result: ARHitTestResult? = hitResults.last if result?.worldTransform != nil{ let matrix: SCNMatrix4 = SCNMatrix4.init((result?.worldTransform)!) let vector: SCNVector3 = SCNVector3Make(matrix.m41, matrix.m42, matrix.m43) movedObject?.position = vector } } } else if recognizer.state == .ended { movedObject = nil } } 

Answer 1

找到了解决方案！ 我在评论中添加了一些解释。

 if (movedObject != nil) { //Normalized-depth coordinate matching the plane I want let projectedOrigin = sceneView.projectPoint((movedObject?.position)!) //Location of the finger in the view on a 2D plane let location2D = recognizer.location(in: sceneView) //Location of the finger in a 3D vector let location3D = SCNVector3Make(Float(location2D.x), Float(location2D.y), projectedOrigin.z) //Unprojects a point from the 2D pixel coordinate system of the renderer to the 3D world coordinate system of the scene let realLocation3D = sceneView.unprojectPoint(location3D) if movedObject?.position != nil { //Only updating Y axis position movedObject?.position = SCNVector3Make((movedObject?.position.x)!, realLocation3D.y, (movedObject?.position.z)!) } } 

有助于理解的post：

unProjectPoint＆projectedOrigin

翻译和unProjectPoint