ios - 在 Scenekit 视图中从网络加载 3d usdz 模型不起作用？

Question

我正在尝试在我的场景套件视图中从网络加载 3d 使用过的模型。模型已正确下载并保存在文件中，但未显示在场景套件视图中。这是我的代码。我没有收到任何错误。不确定到底是什么问题

import UIKit
import SceneKit

class ViewController: UIViewController,URLSessionDownloadDelegate {
    
    @IBOutlet weak var scnView: SCNView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        downloadSceneTask()
    }
    
    
    func downloadSceneTask(){
        
        //1. Get The URL Of The SCN File
        guard let url = URL(string: "url_to_load_3d_model") else { return }
        
        //2. Create The Download Session
        let downloadSession = URLSession(configuration: URLSession.shared.configuration, delegate: self, delegateQueue: nil)
        
        //3. Create The Download Task & Run It
        let downloadTask = downloadSession.downloadTask(with: url)
        downloadTask.resume()
    }
    
    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
        
        //1. Create The Filename
        let fileURL = getDocumentsDirectory().appendingPathComponent("nike.usdz")
        
        //2. Copy It To The Documents Directory
        do {
            try FileManager.default.copyItem(at: location, to: fileURL)
            
            print("Successfuly Saved File \(fileURL)")
            
            //3. Load The Model
            loadModel()
            
        } catch {
            
            print("Error Saving: \(error)")
            loadModel()
        }
        
    }
    
    func getDocumentsDirectory() -> URL {
        
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        let documentsDirectory = paths[0]
        return documentsDirectory
        
    }
    
    func loadModel(){
        
        //1. Get The Path Of The Downloaded File
        let downloadedScenePath = getDocumentsDirectory().appendingPathComponent("nike.usdz")
        
        do {
            
            //2. Load The Scene Remembering The Init Takes ONLY A Local URL
            let modelScene =  try SCNScene(url: downloadedScenePath, options: nil)
            
            //3. Create A Node To Hold All The Content
            let modelHolderNode = SCNNode()
            
            //4. Get All The Nodes From The SCNFile
            let nodeArray = modelScene.rootNode.childNodes
            
            //5. Add Them To The Holder Node
            for childNode in nodeArray {
                modelHolderNode.addChildNode(childNode as SCNNode)
            }
            
            //6. Set The Position
            modelHolderNode.position = SCNVector3(0, 0, 0)
            
            //7. Add It To The Scene
            self.scnView.scene?.rootNode.addChildNode(modelHolderNode)
            
            
        } catch  {
            print("Error Loading Scene")
        }
        
    }
    
    
    
}

Answer 1

我以这种方式加载了模型，它对我有用：

import SceneKit.ModelIO

func loadModel(){
    
    //1. Get The Path Of The Downloaded File
    let downloadedScenePath = getDocumentsDirectory().appendingPathComponent("nike.usdz")
    
    self.scnView.autoenablesDefaultLighting=true
    self.scnView.showsStatistics=true
    self.scnView.backgroundColor = UIColor.blue
    let asset = MDLAsset(url: downloadedScenePath)
    asset.loadTextures()
    let scene = SCNScene(mdlAsset: asset)
    self.scnView.scene=scene
    self.scnView.allowsCameraControl=true
}