Dynamically load xml/dat to create modeltarget looks wired in IOS

Vuforia Version: 10.9

Unity Version: 2021.3

IOS version: 13/14

It works well in Editor, looks weird in IOS like IMG_0066.PNG with no error.

Open an Empty Scene, add ARCamera to the scene, attaching a script into it.

The xml and dat file is the default model target by Vuforia, VuforiaMars_ModelTarget

PS: OnVuforiaStarted2 function is that I directly use downloaded the xml to create modeltarget but it look the same like  IMG_0066.PNG with no error

using System.Collections; using System.Collections.Generic; using System.IO; using UnityEngine; using UnityEngine.Networking; using Vuforia; using static Vuforia.DataSetTrackableBehaviour; using static Vuforia.ModelTargetBehaviour;

public class Tests : MonoBehaviour {     // Start is called before the first frame update

    public GameObject myModelPrefab;

    public ModelTargetBehaviour mObserverBehaviour;

    void Start()     {         VuforiaApplication.Instance.OnVuforiaStarted += OnVuforiaStarted;     }

    private void OnVuforiaStarted2()     {         string xmlPath = Path.Combine(Application.persistentDataPath, "VuforiaMars_ModelTarget.xml");

        mObserverBehaviour = VuforiaBehaviour.Instance.ObserverFactory.CreateModelTarget(             xmlPath,             "VuforiaMars_ModelTarget", TrackingOptimization.DEFAULT);         mObserverBehaviour.enabled = false;         mObserverBehaviour.SetActiveGuideViewIndex(0);         mObserverBehaviour.GuideViewMode = GuideViewDisplayMode.GuideView2D;

        mObserverBehaviour.enabled = true;         Debug.Log(mObserverBehaviour);     }

    private void OnVuforiaStarted()     {         StartCoroutine(download());     }

    IEnumerator download()     {         string xmlPath = Path.Combine(Application.persistentDataPath, "VuforiaMars_ModelTarget.xml");         string datPath = Path.Combine(Application.persistentDataPath, "VuforiaMars_ModelTarget.dat");         yield return StartCoroutine(Get(xmlPath, XMLURL));         yield return StartCoroutine(Get(datPath, DATURL));

                mObserverBehaviour = VuforiaBehaviour.Instance.ObserverFactory.CreateModelTarget(             xmlPath,             "VuforiaMars_ModelTarget", TrackingOptimization.DEFAULT);         mObserverBehaviour.enabled = false;         mObserverBehaviour.SetActiveGuideViewIndex(0);         mObserverBehaviour.GuideViewMode = GuideViewDisplayMode.GuideView2D;

        mObserverBehaviour.enabled = true;         Debug.Log(mObserverBehaviour);

    }

    IEnumerator Get(string path, string url)     {         UnityWebRequest webRequest = UnityWebRequest.Get(url);

        yield return webRequest.SendWebRequest();

        if (webRequest.isHttpError || webRequest.isNetworkError)             Debug.Log(webRequest.error);         else         {                         File.WriteAllBytes(path, webRequest.downloadHandler.data);

            // Verify that the File has been actually stored             if (File.Exists(path))             {                 Debug.Log("File successfully saved at: " + path);             }             else             {                 Debug.Log("Failure!! - File does not exist at: " + path);             }                     }

    }

    // Update is called once per frame     void Update()     {

    }

}