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unity-game-enginevuforia

Stop Tracking images

It is possible that Vuforia, once it has detected an image of your BBDD stop trying to find more images, keeping a 3D object in the last detected position fixed and that you can move the camera in extended tracking mode around the object 3D?

Thanks

Solution

  • It is possible to stop tracking when you want to, and keep a 3D object fixed at the last 2D position on the screen / viewport. But extended tracking is still tracking, so you cannot keep the 3D object fixed at the last position in 3D space once you disable tracking, as that is what tracking is for! :) If you'd like to then use other ways to continue tracking (you mention gyroscope), that is not an easy problem.

    To disable the camera's tracking, but keep the camera feed, you would use something like:

    Tracker imageTracker = TrackerManager.Instance.GetTracker<ObjectTracker>();
if (imageTracker != null)
    imageTracker.Stop();

    It would not make sense to just put that code above in the OnTrackingFound() function in the DefaultTrackableEventHandler (if you are using that, otherwise your equivalent), as a trackable will usually be detected at the edges of the camera image, so if you disable the tracking immediately, the object would be stuck at the edge of your viewport somewhere. So you would probably use a timer, or best is to have the user push a UI button to 'freeze' the object.

    You would also need to change the OnTrackingLost() function in the DefaultTrackableEventHandler to no longer disable the mesh renderer of your 3D object once tracking is 'lost' when tracking is stopped, otherwise the object would disappear.

    Why not switch over to a 3D mode that is not AR, instead, where you can manipulate the object with your fingers on a mobile screen, or with a mouse or keyboard? In other words, disable Vuforia but keep the 'detected' 3D object active on screen. Instead of disabling the ObjectTrackers as in the code above, you would then disable Vuforia entirely, with:

    VuforiaBehaviour.Instance.enabled = false;

    You would still need to edit OnTrackingLost() (or equivalent) to no longer disable the 3D object once tracking is 'lost' when Vuforia is disabled.