Multimodal Rendering of Walking Over Virtual Grounds - Human Walking in Virtual Environments - page 282

Fig. 12.10 Example of a multimodal foot-floor interaction. ( Left ) The frozen pond scenario gen-
erates vibrotactile, acoustic and visual feedback. ( Right ) The snow field is modified according to
the user steps, providing multimodal feedback [ 57 ]
oscillation. A real-time fluid simulator based on Smoothed-Particle Hydrodynamics
and enhanced with bubble synthesis gathers the physical simulation process.
Based on the fluid vibrotactile model [ 12 ] and using the floor tile array described
in Sect. 12.3.4 , Cirio et al. [ 13 ] designed two multimodal scenarios generating haptic,
acoustic and visual feedback. An active shallow pool scenario allowed the user to
walk about a virtual pool with 20 cm of water, splashing water as they stepped
on the pool. A passive beach front scenario allowed users to stand still and feel
waves washing up at their feet on a sandy beach. The floor rendered the vibrotactile
feedback to the user's feet through the appropriate vibrotactile transducers. Acoustic
feedback was also be provided through speakers or headphones. The user's feet
were modeled as parallelepiped rigid bodies and tracked through the floor pressure
sensors. Visual feedback was generated by a GPU meshless screen-based technique
optimized for high frequency rendering [ 12 ] appropriate to the underlying particle
based simulation. The Fig. 12.11 shows the two scenarios.
Fig. 12.11 Interacting with water with multimodal feedback. ( Left ) a shallow water pool. ( Right )
a wave washing up on a beach [ 13 ]