Biomedical Engineering Reference
In-Depth Information
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Virtual worlds do not always have real-world counterparts; without affordances,
how do you cast spells or work alien technology?
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Full body interaction is not always fun: exhaustion, injury and boredom need to
be avoided (or incorporated!).
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Technology limitations may not be able to detect player actions to the levels of
accuracy you desire: occlusion, accuracy, delay, etc.
Therefore, tomeet these challenges, important questionsmust be addressed. These
include: What full body actions are needed? What full body actions are usable? How
can we build natural and compelling full body video game interfaces when we don't
always have the data we desire?
16.4.2 Controlling Travel
Whenever users need to travel through a virtual space, whether with expensive high-
end equipment or common video game controllers, the strategy the user uses to move
through the environment must be addressed. The user needs to be able to indicate
the beginning of travel, the continuation of travel, the cessation of travel, steering
and possibly even define the rate of travel. Traditional controllers simply gave the
user a joystick, where these actions are easily mapped and easily recognized. Natural
gestures complicate the interface design, as there is not a simple mapping between
gesture and result. However, there is a benefit to using natural gestures, such as real
walking or walking in place, which Whitton et al. showed [
25
] was better in several
areas over joystick movement. Real walking in movement are the most preferred,
but can only cover the relatively small ranges of sensors, with walking in place an
accepted substitute for navigating very large areas.
There are a range of options available to you in how you achieve natural travel. In
[
27
], a singleWiimote attached to a hat provided sufficient data to give real movement
within the range of the infrared SBC and to recognize a walking in place gesture.
This approach used Kalman Filters to merge accelerometer, infrared and gyroscope
data into a position vector and orientation quaternion while heuristic recognition
determined if the user was stepping up and down with their feet. In [
28
], a Kinect
provided skeletal data capable of giving real time movement representations in the
sensor's field of view. For walking past this area, a walking in place gesture was used
and determined by user's leg joints. Full-body interaction is a widely studied subject
and while simple game controllers are limited in their data, they are still entirely
capable of providing a natural interface.
