The script [`DistanceManager.cs`](https://github.com/Unity-Technologies/arfoundation-demos/blob/master/Assets/ImageTracking/Scripts/DistanceManager.cs) checks the distances between the tracked images and displays an additional 3D model between them when they reach a [certain proximity.](https://github.com/Unity-Technologies/arfoundation-demos/blob/master/Assets/ImageTracking/Scripts/DistanceManager.cs#L40)
the script [`NumberManager.cs`](https://github.com/Unity-Technologies/arfoundation-demos/blob/master/Assets/ImageTracking/Scripts/NumberManager.cs) handles setting up a [`contraint`](https://docs.unity3d.com/Manual/Constraints.html) (in this case used to billboard the model) on the 3D number objects and provides a function to enable and disabling the rendering of the 3D model.
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