在 RealityKit 中导入多个 .usdz 对象并为其设置动画

Question

我有一个显示 .USDZ 奶牛的简单 RealityKit 场景。我看到了这些问题的几个答案，但我无法将它们实现到我的代码中：

1. 如何播放此文件中内置的动画？
2. 如何才能将第二个对象（比如一匹马）带入场景？

此外，我可以做些什么来清理我的代码/使其更易于阅读？

感谢我能得到的任何帮助！ 谢谢，

import UIKit
import RealityKit
import ARKit

 class WelcomeViewController: UIViewController {

//delay app launch to show splash screen
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        Thread.sleep(forTimeInterval: 3.0)
        // Override point for customization after application launch.
        return true
    }
//end splash screen delay

   @IBAction func gotPressed(_ sender: Any) {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    if let viewController = storyboard.instantiateViewController(withIdentifier: "ViewController") as? ViewController {
        self.present(viewController, animated: true, completion: nil) /// present the view controller (the one with the ARKit)!
    }    }

 }
 class ViewController: UIViewController {

@IBOutlet var arView: ARView!

override func viewDidLoad() {
    super.viewDidLoad()
    
    overlayCoachingView()
    

}
//Overlay coaching view "adjust iphone scan"
func overlayCoachingView () {
    
    let coachingView = ARCoachingOverlayView(frame: CGRect(x: 0, y: 0, width: arView.frame.width, height: arView.frame.height))
    
    coachingView.session = arView.session
    coachingView.activatesAutomatically = true
    coachingView.goal = .horizontalPlane
    
    view.addSubview(coachingView)
    
}//end overlay
{
let cow = try! ModelEntity.load(named: "COW_ANIMATIONS")
let horse = try! ModelEntity.load(named: "White_Horse")

cow.position.x = -1.0
horse.position.x = 1.0

let anchor = AnchorEntity()
cow.setParent(anchor)
horse.setParent(anchor)
arView.scene.anchors.append(anchor)

let cowAnimationResource = cow.availableAnimations[0]
let horseAnimationResource = horse.availableAnimations[0]

cow.playAnimation(cowAnimationResource.repeat(duration: .infinity),
                                    transitionDuration: 1.25,
                                          startsPaused: false)

horse.playAnimation(horseAnimationResource.repeat(duration: .infinity),
                                        transitionDuration: 0.75,
                                              startsPaused: false)}


  }

Answer 1

在 RealityKit API 中播放 .usdz 文件中包含的动画，您可以使用以下代码：

let cow = try ModelEntity.load(named: "cow")
let horse = try ModelEntity.load(named: "horse")

cow.position.x = -1.0
horse.position.x = 1.0

let anchor = AnchorEntity()
cow.setParent(anchor)
horse.setParent(anchor)
arView.scene.anchors.append(anchor)

let cowAnimationResource = cow.availableAnimations[0]
let horseAnimationResource = horse.availableAnimations[0]

cow.playAnimation(cowAnimationResource.repeat(duration: .infinity), 
                                    transitionDuration: 1.25, 
                                          startsPaused: false)

horse.playAnimation(horseAnimationResource.repeat(duration: .infinity), 
                                        transitionDuration: 0.75, 
                                              startsPaused: false)

很遗憾，但在 RealityKit 2.0 中，您只能播放放置在文件中的第一个动画 - 其他动画目前不可用。