Operating instructions

January 9, 2015 version
20 ©January 2015, Oculus VR, LLC
Appendix E - Motion
● The most comfortable VR experiences involve no self-motion for the user besides head
and body movements to look around the environment.
● When self-motion is required, slower movement speeds (walking/jogging pace) are most
comfortable for new users.
● Keep any form of acceleration as short and infrequent as possible.
● User and camera movements should never be decoupled.
● Don’t use head bobbing in first-person games.
● Experiences designed to minimize the need for moving backwards or sideways are most
comfortable.
● Beware situations that visually induce strong feelings of motion, such as stairs or
repeating patterns that move across large sections of the screen.
Speed of Movement and Acceleration
“Movement” here refers specifically to any motion through the virtual environment that is not the
result of mapping the user’s real world movements into VR. Movement and acceleration most
commonly come from the user’s avatar moving through the virtual environment (by locomotion
or riding a vehicle) while the user’s real-world body is stationary. These situations can be
discomforting because the user’s vision tells them they are moving through space, but their
bodily senses (vestibular sense and proprioception) say the opposite. This illusory perception
of self-motion from vision alone has been termed vection, and is a major underlying cause of
simulator sickness.
6
Speed of movement through a virtual environment has been found to be proportional to the
speed of onset for simulator sickness, but not necessarily the subsequent intensity or rate of
increase.
7
Whenever possible, we recommend implementing movement speeds near typical
human locomotion speeds (about 1.4 m/s walking, 3 m/s for a continuous jogging pace) as a
user-configurable—if not default—option.
For VR content, the visual perception of acceleration is a primary culprit for discomfort. This is
because the human vestibular system responds to acceleration but not constant velocity.
Perceiving acceleration visually without actually applying acceleration to your head or body can
lead to discomfort. (See our section on simulator sickness for a more detailed discussion.)
Keep in mind that “acceleration” can refer to any change over time in the velocity of the user in
the virtual world in any direction. Although we normally think of acceleration as “increasing the
6
Hettinger, L.J., Berbaum, K.S., Kennedy, R.S., Dunlap, W.P., & Nolan, M.D. (1990). Vection and simulator
sickness. Military Psychology, 2(3), 171-181.
7
So, R.H.Y., Lo, W.T., & Ho, A.T.K. (2001). Effects of navigation speed on motion sickness caused by an immersive
virtual environment. Human Factors, 43 (3), 452-461