I want to use the same marker twice at the same time and place a 3d model on each.
Is it possible to check which of the two markers is moved so I know which model I have to move?
Hava a marker a unique ID or something like this?
I tried other AR Librarys but these dont track markers, they return every frame a new list of detected markers without relation
to the frame(s) before.
Does this JSARToolKit do too?
If you print two different ID markers, you can manually track them by the ID. There's some code in the detector to track markers frame-by-frame, I guess you could co-opt that to your purposes. Or roll your own, the basic idea is that you hang on to the marker positions from the previous frame and match current frame markers to the closest previous frame markers.
But yeah, print two different ID markers, that's the easiest way. See the video tests with the whale model and 22 cube on the iPhone to see an example of getting the ID of the marker.