ARFoundation 2 image tracking with many ref images and many objects

Hi,
The TrackingState need to be in :

Code (CSharp):

1.  
2. foreach (ARTrackedImage updatedImage in eventArgs.updated)
3.         {
4.             if(updatedImage.trackingState == UnityEngine.XR.ARSubsystems.TrackingState.Tracking)
5.             {
6.                 // The image is track!
7.             }
8.             else if(updatedImage.trackingState == UnityEngine.XR.ARSubsystems.TrackingState.Limited)
9.             {
10.                // Tracking is limited, so the image isn't track but the device try to keep position and rotation with sensor. put destroy function here
11.             }
12.             else
13.             {
14.                 // Tracking is none, but if I remember it's never called (put destroy function here)
15.             }
16.         }
17.  

I hope that help you!

Best,
Alexis

 

Can you show me your code?

 

Hey fabisfab,

I think you just forgot to use the same variable to access the

.trackingstate

in the other if()-statements above. Instead of

trackedObject.trackingState

try

updatedImage.trackingState

. If you look closely at the code @Alexis-Dev postet, you can see, that he used

updatedImage

as well.
And for the Debug.Log() you just need to set a semicolon at the end of the line.

Another valuable tip for anyone having trouble with the images not being detected: check if the filename-extension for the images you load in your ReferenceImageLibrary is ".jpg"! not .JPG, not .jepg, only .jpg.

Hope this helps

 

@fabisfab, @xadvy write the answer!

 

The eventArgs.removed isn't call when the image isn't track. It's used for an other purpose.

Te destroy your prefab when your image isn't track change the functions : UpdateLimitedGameObject and UpdateNoneGameObject by DestroyGameObject

 

You need to instantiate it in UpdateTrackingGameObject.

Check if it's instantiate, if yes: Update the position and rotation of the prefab, if not: Instantiate it.

 

hum, I think there a problem.

Do you Enable and Disable the prefab on tracking/untracking? Or do you Instantiate and Destroy on tracking/untracking?

 

Ok,

I'm little confuse because I'm not using multitracking like that actually...

Go back to:

Code (CSharp):

1. foreach (ARTrackedImage updatedImage in eventArgs.updated)
2.         {
3.             if(updatedImage.trackingState == UnityEngine.XR.ARSubsystems.TrackingState.Tracking)
4.             {
5.                 UpdateTrackingGameObject(updatedImage);
6.             }
7.             else if(updatedImage.trackingState == UnityEngine.XR.ARSubsystems.TrackingState.Limited)
8.             {
9.                UpdateLimitedGameObject(updatedImage);
10.             }
11.             else
12.             {
13.                 UpdateNoneGameObject(updatedImage);
14.             }
15.         }

On the prefabs will appear/disappear, add this component and check Destroy On Removal:

 

@Alexis-Dev
The tracking-state refers to the 'accuracy' of the object that is being tracked:
Tracking: the device is actively tracking this object and updating it
Limited: the device is 'having a hard time' finding/tracking this object. Accuracy might be low, or updates might occur less frequently or not at all
None: the object was found and added, but is not (currently) being updated.

With regards to added/updated/removed:
Added: This object was newly discovered
Updated: The object 'changed'. This can be because it moved, because its location (Pose) became 'more accurate', because its trackingstate changed, etc.
Removed: The object was 'destroyed'. This can happen if for example the pool of objects is full and old objects are being recycled. The implementation is provider-specific.

The definitions above can be applied to each Trackable in ARFoundation. For implementation-specific details you should check the documentation for the underlying XR Plugin (e.g. ARCore, ARKit)

 

Hello sir! I tried to upload my AR Foundation app on Google Play but only flagship phones can search it, but your application can search using my mid-range phone. Any tips? Thanks

 

I don't know why that is happening. I suggest asking here -> https://github.com/Unity-Technologies/arfoundation-samples/issues

 

Hi,

The multiImageTracker works find for me on Android, Using Destroy On removal on my prefab, everything is smooth.
I've got a problem on iOS, exaclty same setting, but the prefab I display on the marker is flickering, looks like it's loosing tracking all the time. Anyone got this problem or a solution to it ?

 

Hi!
I have a problem related to image tracking. When I get too close to the Prefab that is being tracked, even if I still see the image with my phone camera, I completely lose track. Any light on this?

 

Hi, i'm trying make app can switch multi prefab with one image target by button next and button back.Who can help me? thank you

 

Hello,

Just wanting to ask if trackedImage.transform.position always returns (0.0, 0.0, 0.0).
I managed to spawn 2 different gameobjects for different markers. However I thought that I would get different positions for the gameobject, since the markers are at least 1 meter apart from each other

Code (CSharp):

1.    
2. private void OnTrackedImagesChanged(ARTrackedImagesChangedEventArgs eventArgs)
3.     {
4.         var IDAndPrefab = s_ImageGUIDList.Zip(SpawnedObjects, (id, spawnObject) => new { id, spawnObject });
5.        
6.         eventArgs.added.ForEach(trackedImage =>
7.         {
8.             foreach (var obj in IDAndPrefab)
9.             {
10.                 if (trackedImage.referenceImage.guid == obj.id)
11.                 {
12.                     GameObject o = Instantiate(obj.spawnObject, trackedImage.transform);
13.                     debug.text += "position of " +  o.name + " is " + trackedImage.transform.position +"\n"
14.                 }
15.             }
16.         });
17.     }

output I get is:
position of fridge is (0.0, 0.0, 0.0)
position of washer is (0.0, 0.0, 0.0)