I have been trying to use multi target(I want to track all the 20 sides of a icosahedron) and I didn't succeed. What I see in the scene of the Unity editor and what you see in the game is totally different, which is very confusing.
For example, I modified my xml in a way so that in the scene of the Unity editor, the image target is perfectly aligned with my final object. But when I hit play, they are not.
After so many trail and errors, I finally concluded that the above error would appear when you are using a complicated rotation, for example:
Part name="examplemarker" translation="0 0 0" rotation="AD: 0.3911556 0.2607704 -0.8826076 200"
If you just rotate along the x axis(or y, or z), it would work just fine, for example:
Part name="examplemarker" translation="0 0 0" rotation="AD: 0 1 0 153.645645"
You can recreate this and visualize the error easily.
Normally, vuforia would render the marker as a mask, which means that the virtual object behind the marker cannot be seen. Normally, the mask would align with the actual marker in the camera video view perfectly, but when a complicated rotation is used, the mask is not aligned with the actual marker in the camera!!
I really hope Vuforia can fix this or state this in the official documentation.
It you use quaternion in the XML, the rotation in XML won't be recognized in the editor but would appear exactly the same with an axis-angle rotation during runtime, both in the editor or on Android.
I have been trying to create the multi target for nearly two months. Would really appreciate some help!