Is there a way to set the zoom level for the camera view (the input image)?

Frame markers are easy to grab and use (we provide 512 of them) and are lightweight to process, so you can include all 512 in a single project. They also give you flexibility on the inner image, as you suggested. The downside is that you have to have the entire marker in view to track it.

Good image targets (those with a nice set of features) provide more robust tracking. You can focus on a subset of the image, zoom in and out, and track at a wide range of angles.

Support for gingerbread tablets will be added in a future release.

As far as world position goes, that depends on how you setup the World Center parameter on the AR Camera. If you set it to NONE, then the camera stays stationary while all the targets move in front of it. If you set it to AUTO, one target is stationary (the first one detected) while the camera and all other targets move in relation to it. You can pick a particular target to be the world center with USER, and then it will never move in the scene. In any case, you can just query the transform of the trackable like any other Unity object. Please note, if you have several trackables in your scene then the relative sizes in Unity should match the relative sizes of your printed targets (for occlusion to work correctly).

I'm guilty of using print statements for debugging, I don't have much experience with the Unity debugger. Perhaps someone else can chime in here :)

- Kim