Vuforia allows you to track multiple targets simultaneously which unlocks opportunities to create concepts where interactions between targets occur as two or more targets are detected and in the same view.
As a developer, you will need to consider the maximum number of targets you wish to track simultaneously and how it will affect the user experience and the performance of the device. Each target that is active in the camera’s field of view (FoV) will increase the computational load on the device.
Additionally, consider the targets’ physical sizes and the maximum distances from which a set of targets should be detected and tracked together. The greater the number of targets, the farther the camera needs to be from them to capture them all in its FoV.
To take into account these factors (user experience and performance) it is best to set a maximum of targets that can be tracked simultaneously.