Real-Time 3D Fluid Interaction with a Haptic User Interface

Abstract

Imagine you are playing a videogame in which you impersonate a wizard who needs to create a potion in order to enchant your enemies. Through a desktop haptic probe, shaped as a baton, you are able to stir and feel the magical fluid inside a bowl. As you follow the potion recipe, you feel how the fluid changes its viscosity, density, velocity and other properties. Various hapto-visual user interfaces enable users to interact in three-dimensions with the digital world and receive realistic kinesthetic and tactile cues in a computer-generated environment. So far solid or deformable objects have been experimented for haptic-tactile feedback. In this paper we innovate by devising techniques that enable the haptical rendering of shape-less objects, such as fluids. Focusing on the real-time performance to enhance the user's experience, the system imitates the physical forces generated by the real-time fluid animation, stirring movements and fluid changes. We achieved real-time 3D fluid and overcame the challenges that arise during the integration of both haptics and graphics workspaces, the free-view visualization of 3D fluid volume, and the rendering of haptic forces. These fluid interaction techniques with haptic feedback have wide possible applications including game development and haptic communities. INTRODUCTIONHaptics, which refers to the technology which stimulates the users' sense of touch, has been increasing in popularity because of the powerful enhancements that it brings to the 3D humancomputer interaction experience. Haptics allow users to literally touch and feel characteristics about computer-generated objects such as texture, roughness, viscosity, elasticity, and many other properties, and research has mainly been oriented towards the modeling of solid structures. However, little research has targeted the haptic rendering of shape-less objects, such as fluids. Fluid animation is of great popularity in computer graphics and animation. However, it is difficult to achieve a real-time stable simulation due to the heavy computation required to solve the non-linear Navier-Stokes equation.Our goal is to combine both fields, fluid animation and its haptic rendering, to offer an interactive experience between 3D fluid and the user. Our motivation is to produce a system that brings human-computer interaction to real-time fluid animations, so that users can appreciate and feel the properties of a fluid simulation via a haptic interface.Several applications could rise from this integration. Videogames, for instance, could be brought to a higher degree of interaction by providing an interface that enables players to feel the stirring of fluids in order to achieve a game task. Nintendo's recent Wii games [23] are an example of the industry's interest for higher interactive applications. Haptics would allow players to feel the physical properties of in-game objects. In addition, medical applications could imitate the blood flow in a patient's cardiovascular system. In combination with audio and video displays, this te...

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