I'm doing an internship, in which I'm working on a rehabilitation game for amputated people (the goal is to help diminishing phantom pain).
The game is using a Kinect and an Oculus Rift, and developed on Unity3D. A virtual avatar is displayed in the Oculus as in a FPS and follow the movement of the user thanks to the Kinect. The goal being that the person with a missing limb can see himself with a full body. (AR is added later)
It is already kind of functional, but I have to improve the calibration. For that, I need to place in the virtual world a marker where the Kinect physically stands to allow the user to fix it when wearing the Oculus.
I didn't find clear enough documentation (for me at least) about the structures of the data send by the Kinect. I thing I should find the rotation of the user's body according to the Kinect, and use it to place the marker. For example, if the user is 45° from facing directly the Kinect, I should place the marker at -45° from the line of sight of the Oculus. Easy to say, but I'm not sure how to retrieve this information from the Kinect data.
According to this page, the kinect is located at the origin. I assume that you where able to read the users position from the kinect, since you say that you placed the avatar properly.
If the avatar is indeed placed by the kinect, then just put your maker in (0, 0, 0) and that should be the kinect's position