Infinite Walking in VR
In the ever-evolving landscape of virtual reality (VR) technology, a
number of key hurdles remain. But a team of computer scientists have
tackled one of the major challenges in VR that will greatly improve user
experience--enabling an immersive virtual experience while being
physically limited to one's actual, real-world space. The research team
will present their work at SIGGRAPH 2018.
A user wears the
researchers' experimental setup -- a Vive HMD augmented with SMI gaze
tracking. Superimposed are the top view of the recorded movements of the
physical path in a 3.5 m × 3.5 m real room and the virtual path in a
much larger 6.4 m × 6.4 m synthetic space. The team demonstrates that
saccades can significantly increase the rotation gains during
redirection without introducing visual distortions or simulator
sickness. Their new method can be applied to large, open virtual spaces
and small physical environments for room-scale VR.
Computer scientists from Stony
Brook University, NVIDIA and Adobe have collaborated on a computational
framework that gives VR users the perception of infinite walking in the
virtual world--while limited to a small physical space. The framework
also enables this free-walking experience for users without causing
dizziness, shakiness, or discomfort typically tied to physical movement
in VR. And, users avoid bumping into objects in the physical space while
in the VR world.
To do this, the researchers focused on manipulating a user's walking
direction by working with a basic natural phenomenon of the human eye,
called saccade. Saccades are quick eye movements that occur when we look
at a different point in our field of vision, like when scanning a room
or viewing a painting. Saccades occur without our control and generally
several times per second. During that time, our brains largely ignore
visual input in a phenomenon known as "saccadic suppression"--leaving us
completely oblivious to our temporary blindness, and the motion that our
"In VR, we can display vast universes; however, the physical spaces in
our homes and offices are much smaller," says lead author of the work,
Qi Sun, a PhD student at Stony Brook University and former research
intern at Adobe Research and NVIDIA. "It's the nature of the human eye
to scan a scene by moving rapidly between points of fixation. We
realized that if we rotate the virtual camera just slightly during
saccades, we can redirect a user's walking direction to simulate a
larger walking space."
Using a head- and eye-tracking VR headset, the researchers' new method
detects saccadic suppression and redirects users during the resulting
temporary blindness. When more redirection is required, researchers
attempt to encourage saccades using a tailored version of subtle gaze
direction--a method that can dynamically encourage saccades by creating
points of contrast in our visual periphery.
The team who authored the research, titled "Towards Virtual Reality
Infinite Walking: Dynamic Saccade Redirection," will present their work
at SIGGRAPH 2018, held 12-16 August in Vancouver, British Columbia. The
annual conference and exhibition showcases the world's leading
professionals, academics, and creative minds at the forefront of
computer graphics and interactive techniques.
To date, existing methods addressing infinite walking in VR have limited
redirection capabilities or cause undesirable scene distortions; they
have also been unable to avoid obstacles in the physical world, like
desks and chairs. The team's new method dynamically redirects the user
away from these objects. The method runs fast, so it is able to avoid
moving objects as well, such as other people in the same room.
researchers ran user studies and simulations to validate their new
computational system, including having participants perform game-like
search and retrieval tasks. Overall, virtual camera rotation was
unnoticeable to users during episodes of saccadic suppression; they
could not tell that they were being automatically redirected via camera
manipulation. Additionally, in testing the team's method for dynamic
path planning in real-time, users were able to walk without running into
walls and furniture, or moving objects like fellow VR users.
"Currently in VR, it is still difficult to deliver a completely natural
walking experience to VR users," says Sun. "That is the primary
motivation behind our work--to eliminate this constraint and enable
fully immersive experiences in large virtual worlds."
Though mostly applicable to VR gaming, the new system could potentially
be applied to other industries, including architectural design,
education, and film production.