I want to load a 3d usdz blob into a view, but since I only have the data object, I'm trying to initialize the scene with that with no luck.

To that, I initialize the SCNSceneSource() and then open it using .scene().

Now what I don't understand: If I use a URL and load the scene directly - it works. If I use a Data object on the same URL it doesn't.

Apple docs says, the data should be of type NSData but that seems wrong.

import SceneKit

let url = URL(string: "file:///Users/thilo/Desktop/Input/UU2.usdz")!
// working
let src_ok = SCNSceneSource(url: url)
let scn_ok = src_ok?.scene(options: nil, statusHandler: {
    a,b,c,d in print("OK: \(a) \(b) \(String(describing: c)) \(d) ")
})
print("Ok: \(scn_ok)")

// Not working?
let data    = try! Data(contentsOf: url)
let src_bad = SCNSceneSource(data: data)
let scn_bad = src_bad?.scene(options: nil, status handler: {
    a,b,c,d in print("BAD: \(a) \(b) \(String(describing: c)) \(d) ")
})
print("Failed: \(scn_bad)")

running on Playground says:

Ok: Optional(<SCNScene: 0x6000038e1200>)
BAD: 0.0 SCNSceneSourceStatus(rawValue: 4) nil 0x000000016fa948bf 
BAD: 0.0 SCNSceneSourceStatus(rawValue: 4) nil 0x000000016fa942af 
BAD: 0.0 SCNSceneSourceStatus(rawValue: -1) Optional(Error Domain=NSCocoaErrorDomain Code=260 "Could not load the scene" UserInfo={NSLocalizedDescription=Could not load the scene, NSLocalizedRecoverySuggestion=An error occurred while parsing the COLLADA file. Please check that it has not been corrupted.}) 0x000000016fa942af 
Failed: nil

What am I missing?

CodePudding user response：

potential solution could be to verify the format of the data object and ensure that it is a valid COLLADA file.

import Foundation

let url = URL(string: "file:///Users/thilo/Desktop/Input/UU2.usdz")!

let data = try! Data(contentsOf: url)
print("Data size: \(data.count)")
print("Data format: \(data.description)")

you usually get these types of errors when the data wasn't properly formatted

CodePudding user response：

SCNSceneSource doesn't support .usdz

SCNSceneSource object supports only .scn, .dae and .abc file formats.

import SceneKit
import Cocoa

class GameViewController : NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        if let url = URL(string: "file:///Users/swift/Desktop/ship.scn") {
    
            let data = try! Data(contentsOf: url)
            let source = SCNSceneSource(data: data)
    
            let sceneView = self.view as! SCNView
            sceneView.scene = source?.scene()
        }
    }
}

To load .usdz model, use SCNScene object

import SceneKit
import Cocoa

class GameViewController : NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let url = URL(fileURLWithPath: "/Users/swift/Desktop/ship.usdz")

        do {
            let scene = try SCNScene(url: url)
            let sceneView = self.view as! SCNView
            sceneView.scene = scene
            sceneView.autoenablesDefaultLighting = true
        } catch {
            print(error.localizedDescription)
        }
    }
}