Holo-remotes were extremely sophisticated and realistically rendered holograms used for self-defense training. To create a functioning holo-remote, a grid of computer sensors was set up within a room so that the computer controlling the holoprojector could track the movements of the user and simulate realistic hit detection on the part of the hologram that was being projected. Though the result would be a realistic depiction of an adversary, the hologram itself could do no harm to the user.