Biomedical Engineering Reference
In-Depth Information
14.3.3 Designing Experiences for Redirected Walking
The effectiveness of redirected walking depends largely upon the users' motions—the
virtual world can be rotated faster to redirect the user's walking path during turns
of the head or body. Unfortunately, user behavior in immersive simulators is often
unpredictable, and if the user chooses to follow an unexpected route, the redirected
walking technique may fail to prevent them from exiting the tracking space. How-
ever, the content of the virtual world can be designed to support redirected walking
by subtly influencing and guiding user behavior. We have identified three design
mechanics that can be leveraged to maximize the effectiveness of redirected walk-
ing: attractors, detractors, and distractors. We further suggest that in the context of
immersive training, these mechanics should be ecologically valid and seamlessly
merged into the content of the training scenario, so that the redirection will be as
unintrusive as possible.
Attractors
are designed to make the user walk towards a specific location or
direction. For example, an environment to train soldiers how to search for improvised
explosive devices may include suspicious objects or containers that attract users to
come investigate them. Alternatively, avatars also have shown to be highly promising
for supporting redirected walking (e.g. [
11
]). This may be especially useful in the
context of training, since soldiers typically operate in squads. A virtual squadmate
can move around the virtual environment and communicate with users to entice them
to walk towards locations that would be advantageous for redirection.
Detractors
are obstacles in the virtual environment that can be employed to prevent
users from approaching inaccessible areas or force them to take a less direct route
through the environment. For example, researchers have used partially opened doors
to elicit body turns while navigating through doorways instead of walking straight
through, thus allowing greater amounts of redirection to be applied [
2
]. Again, we
suggest that an avatar may be ideally suited for such a role. Studies of proxemics
have shown that people will attempt to maintain a comfortable distance from another
person, and this social behavior has also been replicated when interacting with a
virtual character [
8
]. If the user is approaching the boundaries of the tracking space,
a virtual squadmate might walk in front, thereby forcing the user to turn and providing
an opportunity for redirection.
Distractors
were first introduced by Peck et al. to capture the user's attention and
elicit head turns during reorientation [
12
]. This design mechanic has many potential
uses in training environments. For example, explosions, gunfire, and vehicles are
just a few events that might be encountered in a military combat simulator. These
phenomena provide opportune moments for redirection, while the user's attention
has been diverted away from the act of walking. We suggest that any practical training
scenario seeking to use redirected walking techniques should be designed to make
maximal use of these opportunities for distraction.
