While I was browsing the internet and looking for a suitable VR headset, I came across some terminologies that I couldn’t understand like 3DoF and 6 DoF. So, I did some research and found some answers. Here’s my summary for you guys.

3 DoF

3 Degrees of freedom

6 DoF

6 Degrees of freedom

What is DoF (Degrees of Freedom)?

DoF (Degrees of Freedom), you’ll see that word a lot in terms of explaining the limitations or specs of the VR system.Also keep in mind Degrees in DoF doesn’t mean the angular degrees that measure of a plane angle, DoF refers to the movement of a body within space. DoF takes in account the movement of head in space or how we account for the heads position and orientation. It could be explained as possible ways in which an object can move.
So, what does that mean, it means that the VR device got to take into account the position of the body, that where the body is located within the virtual space it also got to take care of the orientation so it accounts for both position and orientation.

What is Position & Orientation ?

Position and Orientation are also known as Translational and Rotational Movement respectively. Orientation is the angle of that body within space. The position of the body is basically the X,Y,Z coordinates of that object in space.

Position/Translational Movement

  • Moving up and down (elevating)
  • Moving left and right (strafing)
  • Moving forward and backward(surging)

Orientation/Rotational Movement

  • Swivels left and right (yawing)
  • Tilts forward and backward (pitching)
  •  Pivots side to side (rolling)

3 DoF

The entry level head mounted display offers 3DOF, three degrees of freedom which allows one to rotate the head in three planes with pitch tilting forward and backward on the x-axis yaw turning left and right on the y-axis and roll tilting side-to-side on the z-axis. That is the basic form of body tracking in virtual reality and relies on the inbuilt sensors (accelerometers, gyroscopes and magnetometers) that phones use to measure movement. In essence, these tools allow a device to measure how it is moving in three types of directional rotation (ie 3DoF). Certain user movements are registered by these sensors and translated so that the VR program running on the phone or VR headset can respond in real-time.

Position & Orientation are also known as
Translational & Rotational Movement respectively.

6 DoF

A more sophisticated version of positional tracking is Six Degrees of Freedom (DoF), which incorporates the three rotational measurements (rolling, pitching and yawing) and adds three further directional movements “sway”move left and right on the x-axis “heave” move up and down on the y-axis and “surge” move front and back on the z-axis, that allow a person to physically move around in a virtual space, rather than simply standing in one spot.
6 DOF comes with more advanced head mounted displays and the higher freedom means that the user is able to engage with movement together with stereoscopic and spatial audio, that intensifies the sense of existence. The more movement the greater the experience in VR because a person can suspend disbelief from real world to the virtual world and engage with the content in a more immersive manner.
This type of tracking is crucial for whole-room VR experiences and gives the user a lot more room to explore locations, inspect details and (perhaps as crucial) to dodge virtual bullets.With Six Degrees of Freedom (6DoF) both the headset and the controllers worn by the user are tracked. This can be achieved either by using external sensors to capture movement (known as outside-in tracking) or using sensors attached to the headset itself (called inside-out tracking) which continuously relays the positions of the headset and controllers back to the computer.

Which headset is right for you ?

Deciding on which type of headset you buy will certainly depends on the application you or your business needs it for. For a stationary experience such as watching movies on Netflix or viewing a virtual scene, a 3DoF headset might be suitable. However, for any VR experience where the user needs the freedom to explore, 6DoF tracking becomes a necessity.
It is always worth looking online and watching reviews of the devices that suits you the most.