- See also: Positional tracking
Tracking volume is a term used to describe the size of the area within which the tracking camera is still able to capture user’s physical movements. Usually, the tracking volume is determined by camera’s horizontal and vertical field of view.
For practical reasons, most virtual reality experiences have been limited to just sitting. Most users simply do not have an area large enough to take advantage of all possibilities that large-scale tracking offers. Despite this fact, Oculus has successfully demonstrated a room-sized tracking volume experience at E3 2015. By using two cameras mounted on a wall a few feet away from each other, the company has managed to cover an area of approximately 12x12 feet. The tracking space extended from wall to wall and from floor to ceiling.
Tracking volume for each HMD
Default 15 feet by 15 feet room
Oculus Rift DK2
- See also: Oculus Rift DK2
72°H x 52°V (8.2 feet range)
Oculus Rift CV1
- See also: Oculus Rift CV1
100°H x 70°V (>18 feet range)
- See also: HTC Vive
120°H x 120°V (>21 feet range)
- See also: PlayStation VR
72°H x 45°V (15 feet range estimate)
Commonly used positional tracking technologies
There are many different positional tracking technologies used to determine the exact position of the user inside the tracking volume and change the viewpoint accordingly. Such tracking helps to blur the line between virtual experiences and the real world.
Magnetic tracking uses a magnetic field and its rotation and strength in relation to a base station to very accurately measure movement and rotation. This technology has already been successfully implemented in devices such as Razor Hydra. This device allows players to experience PC games in a new way and interact with the game world in three dimensions. The biggest downside to magnetic tracking is the relative ease with which it can be disrupted by conductive materials near sensors.
Acoustic tracking works with multiple speakers and receivers placed in the environment. Acoustic signals are sent in precisely timed bursts. This time is subsequently used to calculate changes in distance and orientation. This type of positional tracking is highly prone to interference due to ambient noise.
Marker-less Optical Tracking
In those cases where the geometry of scene or object is already known, it is possible to utilize various object recognition methods to determine changes in real-time without the need to place any markers on the object.