Biomedical Engineering Reference
In-Depth Information
to the slope of the virtual ground. While the user walks on the flat real ground,
these camera effects are injected in the virtual environment and rendered through a
head-mounted display. Experimental results showed that these visual effects are very
efficient for the simulation of two canonical shapes: bumps and holes located on the
ground. Interestingly, a strong “orientation-height illusion” is found, as changes in
pitch viewing orientation produce perception of height changes (although camera's
height remains strictly the same in this case).
Other pseudo-haptic effects could be envisioned to improve the sensation of
walking over virtual grounds. One promising direction would be the simulation of
pseudo-haptic materials with the King-Kong effects: the current simple visual vibra-
tion patterns could give way to physically based patterns representing the impact
on different materials (wood, rubber, metal), as demonstrated in previous work in
a hand-based interaction context [
40
]. Extension of the pseudo-haptic walking has
also been performed for auditory rendering by Turchet et al. [
101
] for simulating
bumps and holes on different ground surfaces.
12.4 Conclusion
The present chapter proposed to review interactive techniques related to multimodal
rendering of walking over virtual ground surfaces. We successively detailed exist-
ing auditory, vibrotactile and then multimodal rendering approaches. As for today,
high-end VR setups and devices dedicated to multi-sensory walking in virtual envi-
ronments could succeed in providing realistic acoustic and haptic feedback cor-
responding to complex scenarios. It becomes indeed possible to walk over snow,
beaches, or dead leaves, and hear and feel the corresponding walking sensations
using sonic shoes or haptic floors. Besides, some cross-modal effects enable to fool
the senses and perceive changing ground properties.
Through the description of different rendering approaches, the chapter provided
some concrete examples of how sensations accompanying walking on natural ground
surfaces could be rich, multimodal and highly evocative of the settings in which they
occur. We believe including multimodal cues when exploring virtual environments
could bring major benefits in various applications, such as for medical rehabilita-
tion for gait and postural exercises, training simulations, and entertainment, for an
improved immersion within rich virtual environments and compelling interaction
with realistic virtual grounds.
References
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periodicity to randomness. In: EGS XXVII general assembly
2. Alava MJ, Nukala PKVV, Zapperi S (2006) Statistical models of fracture. Adv Phys
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