Question Using Raycast with Prefabs Instantiated using Tracked Image Manager

Hi There,

I have been trying for a while and it seems that the prefab spawned by the tracked image manager cant be hit by the physics raycast. If I drag the same prefab into the scene the raycast hit's it fine, does anyone know why this is occurring or how to fix it?

 

How are you verifying whether the prefab is hit?.

Does the tracked image manager make the instantiated prefab a child of another gameobject? If so then you're probably getting the parent's gameobject info and not the actual prefab.

If the above is true then use something like: Debug.Log(hit.collider.transform.name); to see the actual hit object's name and not the parent's.

 

Thank you for your reply I believe that is what I am using, this is how I instantiate the prefab.

Code (CSharp):

1. using System;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.XR.ARFoundation;
5. using UnityEngine.XR.ARSubsystems;
6. [RequireComponent(typeof(ARTrackedImageManager))]
7. public class PlaceTrackedImages : MonoBehaviour
8. {
9.     private ARTrackedImageManager _trackedImagesManager;
10.     public GameObject[] ArPrefabs;
11.     private readonly Dictionary<string, GameObject> _instantiatedPrefabs = new Dictionary<string, GameObject>();
12.     void Awake()
13.     {
14.         _trackedImagesManager = GetComponent<ARTrackedImageManager>();
15.     }
16.     private void OnEnable()
17.     {
18.         _trackedImagesManager.trackedImagesChanged += OnTrackedImagesChanged;
19.     }
20.     private void OnDisable()
21.     {
22.         _trackedImagesManager.trackedImagesChanged -= OnTrackedImagesChanged;
23.     }
24.     private void OnTrackedImagesChanged(ARTrackedImagesChangedEventArgs eventArgs)
25.     {
26.         foreach (var trackedImage in eventArgs.added)
27.         {
28.             var imageName = trackedImage.referenceImage.name;
29.             foreach (var curPrefab in ArPrefabs)
30.             {
31.                 if (string.Compare(curPrefab.name, imageName, StringComparison.OrdinalIgnoreCase) == 0 && !_instantiatedPrefabs.ContainsKey(imageName))
32.                 {
33.                     var newPrefab = Instantiate(curPrefab, trackedImage.transform);
34.                     _instantiatedPrefabs[imageName] = newPrefab;
35.                 }
36.             }
37.         }
38.         foreach (var trackedImage in eventArgs.updated)
39.         {
40.             _instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(trackedImage.trackingState == TrackingState.Tracking);
41.         }
42.         foreach (var trackedImage in eventArgs.removed)
43.         {
44.             Destroy(_instantiatedPrefabs[trackedImage.referenceImage.name]);
45.             _instantiatedPrefabs.Remove(trackedImage.referenceImage.name);
46.         }
47.     }
48. }

And this is the code I used for the raycast on touch, it prints the name of what was hit to the TMP text element

Code (CSharp):

1. using System.Collections.Generic;
2. using UnityEngine;
3. using UnityEngine.UI;
4. using TMPro;
5.  
6. public class PlacementWithManySelectionController : MonoBehaviour
7. {
8.     private Camera arCamera;
9.     private Vector2 touchPosition = default;
10.     public Button swapObject;
11.     public TextMeshProUGUI objectName;
12.     public int object1TypeTracker = 0;
13.     public int object2TypeTracker = 0;
14.     public string collidedObject;
15.  
16.     void Awake()
17.     {
18.         objectName.text = "";
19.         swapObject.onClick.AddListener(SwapObjectTracker);
20.     }
21.  
22.     void SwapObjectTracker()
23.     {
24.         if (collidedObject.Contains("RoboSparky"))
25.         {
26.             if (object1TypeTracker == 0)
27.             {
28.                 object1TypeTracker = 1;
29.                 objectName.text = "Robo Sparky";
30.             }
31.  
32.             if (object1TypeTracker == 1)
33.             {
34.                 object1TypeTracker = 0;
35.                 objectName.text = "Robo Sparky";
36.             }
37.         }
38.  
39.         if (collidedObject.Contains("ASUPitchfork"))
40.         {
41.             if (object2TypeTracker == 0)
42.             {
43.                 object2TypeTracker = 1;
44.                 objectName.text = "ASU Pitchfork";
45.             }
46.  
47.             if (object2TypeTracker == 1)
48.             {
49.                 object2TypeTracker = 0;
50.                 objectName.text = "ASU Logo";
51.             }
52.         }
53.     }
54.  
55.     void Update()
56.     {
57.         if (Input.touchCount > 0)
58.         {
59.             Touch touch = Input.GetTouch(0);
60.  
61.             touchPosition = touch.position;
62.  
63.             if(touch.phase == TouchPhase.Began)
64.             {
65.                 Ray ray = arCamera.ScreenPointToRay(touch.position);
66.                 RaycastHit hitObject;
67.                 if (Physics.Raycast(ray, out hitObject))
68.                 {
69.                     collidedObject = hitObject.collider.gameObject.name;
70.                     objectName.text = collidedObject;
71.                 }
72.             }
73.         }
74.     }
75. }

 

I'm surprised your 2nd script works. Why isn't your arCamera public for setting in the inspector?.

Or can you try tagging your Camera 'MainCamera' and then use: Camera.main.ScreenPointToRay(touch.position)?.

 

Yea now that you mention it I am not sure, let me try making it public then attaching the ar camera to it, I will let you know if that works

 

Thank you for your help, adding the camera fixed part of it, then removing the AR plane manager fixed the other issue, I guess it was creating planes over my objects and I was selecting them instead of my objects

 

Awesome!