We present a prototype Mixed Reality (MR) system with a hybrid interface to support remote collaboration between a local
worker and a remote expert in a large-scale work space. By combining a low-resolution 3D point-cloud of the environment
surrounding the local worker with a high-resolution real-time view of small focused details, the remote expert can see a virtual
copy of the local workspace with an independent viewpoint control. Meanwhile, the export can also check the current actions
of the local worker through a real-time feedback view. We conducted a pilot study to evaluate the usability of our system by
comparing the performance of three different interface designs (showing the real-time view in forms of 2D first-person view, a
2D third-person view and a 3D point cloud view). We found no difference in average task performance time between the three
interfaces, but there was a difference in user preference
