Degrees of Freedom
Understanding Movement in XR
In spatial computing, it is essential to understand the possible movement a user can perform so we can plan the interactions based on that. This movement is referred to as the Degree of freedom. An object can move in six different ways within a space, which can be categorized into rotational and translational, i.e., three movements in each category, respectively.
Degrees of freedom (DoF) refer to the number of basic ways a rigid object can move through 3D space.
3DoF means we can track rotational motion but not translational. For the headset, that means we can track whether the user has turned their head left or right, tilted it up or down, or pivoted left and right. With 3DoF, users can’t move in space.
6DoF means we can track translational motion along with the rotational motion. That means we can track whether the user has moved forward, backward, laterally, or vertically along with other tracking options from rotational movements.
Rotational Movements:
Rotational movements are used to determine where a user is currently looking or pointing their controller.
The three possible rotational movements are Pitch, Yaw, and Roll.
Roll:
Roll is where the object rotated along the X-axis, which translated to pivoting your head to left or right or rotating the reticle in case of the controller.
Pitch:
Pitch is when the object is rotated along the Y-axis, which translates to looking up or down for the human head or moving the reticle up or down when using the controller.
Yaw:
Yaw is the movement in which the object is rotated along the Z-axis, which translates to looking left or right for the human head or moving the reticle sideways using the controller.
Translational Movements:
Translational movements are used to determine where the user or a controller is located in the 3D space.
The three possible translational movements are Elevating, Strafing, and Surging.
Surging:
Surging is the movement of an object along the X-axis, which translates to walking forward or backward for a human or moving the control front and back.
Strafing:
Strafing is the movement of an object along the Y-axis, which translates to stepping sideways for a human or moving the control to left or right.
Elevating:
Elevating is the movement of an object along the Z-axis, which translates to bending down or standing up for a human or rising a controller up or down.
Translational movements allow a user to move in a 3D space rather than just standing or sitting at a single spot.
To have a more immersive experience, 6DoF is mandatory in XR experiences so a user can move more naturally in the 3D space.
