Hello,

I'm relatively new to Unity and AR project and I'm stuck trying to dynamically add a 3D model to an Image Target. I have the following error and cannot understand where is the problem: error CS0246: The type or namespace name 'ITrackableEventHandler' could not be found (are you missing a using directive or an assembly reference?)

Here it is the code I'm using which's been taken from https://library.vuforia.com/content/vuforia-library/en/articles/Solution/Working-with-Vuforia-and-Unity.html#dynamically-add

using UnityEngine;

using Vuforia;

using System.Collections;

public class MyPrefabInstantiator : MonoBehaviour, ITrackableEventHandler {

  private TrackableBehaviour mTrackableBehaviour;

  public Transform myModelPrefab;

  // Use this for initialization

  void Start ()

  {

    mTrackableBehaviour = GetComponent<TrackableBehaviour>();

    if (mTrackableBehaviour) {

      mTrackableBehaviour.RegisterTrackableEventHandler(this);

    }

  }

  // Update is called once per frame

  void Update ()

  {

  }

  public void OnTrackableStateChanged(

    TrackableBehaviour.Status previousStatus,

    TrackableBehaviour.Status newStatus)

  {

    if (newStatus == TrackableBehaviour.Status.DETECTED ||

        newStatus == TrackableBehaviour.Status.TRACKED ||

        newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)

    {

      OnTrackingFound();

    }

  }

  private void OnTrackingFound()

  {

    if (myModelPrefab != null)

    {

      Transform myModelTrf = GameObject.Instantiate(myModelPrefab) as Transform;

      myModelTrf.parent = mTrackableBehaviour.transform;

      myModelTrf.localPosition = new Vector3(0f, 0f, 0f);

      myModelTrf.localRotation = Quaternion.identity;

      myModelTrf.localScale = new Vector3(0.0005f, 0.0005f, 0.0005f);

      myModelTrf.gameObject.active = true;

    }

  }

}

Could anyone help me? Thanks in advance!