SPH haptic interaction with multiple-fluid simulation

Physics-based fluid interaction plays an important role in computer animation, with wide applications in virtual reality, computer games, digital entertainment, etc. For example, in virtual reality education and games, we often need fluid interactions like acting as an alchemist to create a potion by stirring fluid in a crucible. The traditional input devices such as a mouse and keyboard can basically input 2D information without feedback. In recent years, the continuous development of haptic device not only can achieve six degrees-of-freedom input, but also can calculate the force in virtual scenes and feedback to the user to make a better virtual experience. How to use haptic device in different kinds of virtual fluid scenarios to provide better experience is an important issue in the field of virtual reality. On the other hand, the researches on multiple-fluid interaction especially based on smoothed particle hydrodynamics (SPH) method are very lacking. Therefore, we study the key techniques of haptic interaction with SPH multiple-fluid to compensate this defect in computer graphics community. Different from the single-phase flow, interaction with multiple-fluid flow has difficulties in the realization of properties of different phases. After adding the multiple-fluid simulation, it is also important to keep haptic interaction real time. Our research is based on the mixture model. We guarantee the authenticity of multiple-fluid mixing effect while changing the drift velocity solver to improve efficiency. We employ a unified particle model to achieve rigid body–liquid coupling, and use FIR filter to smooth feedback force to the haptic device. Our novel multiple-fluid haptic simulation can provide an interactive experience for mixing liquid in virtual reality.