WebXR getViewerPose ( referenceSpace )

What is the correct way to retrieve headset orientation data (x, y, z or matrix) in Three.js (Three.js/WebXR) with respect to referenceSpace?

(Reason: I need to modify textures and add/remove some objects whose presence needs to be conditioned by the exact orientation of the head of the user. There are no examples covering/demoing accessing headset orientation data)

Just for clarification: Why don’t you just use the orientation of your camera? When presenting, its world matrix is updated with the values from the internal VR camera.

what about the position, let say my simple camera is set in a world at center ( 9000,5,4500 ),
the webxr camera just sets whatever i do to 0,0,0, how to offset the webxr camera ? thx