Real time crying simulation using fluid particles interaction technique

Abstract

The enhancement of emotional expression of virtual human in extreme situation such as, crying or sweating required physics effect that involved fluid behavior. The aim of this research is to utilize Facial Action Coding System (FACS) and Smooth Particle Hydrodynamic (SPH) methods to effectively provide an efficient display in computer facial animation. This research presents two techniques for generating extreme expression in 3D facial animation, the facial action coding system is employed to describe and create facial expressions. It breaks down facial actions into minor units known as Action Units (AU’s). Emotion facial expressions generated are based on independent action unit’s combination. The SPH method technique is used to generate crying teardrops according to rules of physics. Each particle in tears drop is simulated and controlled by SPH rule. The created expressions include sadness and happiness by FACS then add the tears that followed the SPH method rules to provide an avatar tears displaying affectively as an extreme expression. The enforcement of the proposed system is able to fuse both FACS & SPH used in facial animation and fluid simulation, to create a system able to express, and implement the extreme expressions in facial animation. The results obtained in this research, were generated tears consist of 100 particles and achieved an average 55.5 Frame per Second (FPS) and were considered it as the final result, the values that used in this research is 0.0108 N./m2 for pressure, 1 kg/(m·s) for viscosity, 1 m/s2 for Gravity as a physics parameters that affect the tears, the position of the tears source is set at the middle and outer end of each eye. Modeling the muscles movement for extreme expressions such as, crying or the rest of expressions. In future work, this research seeks to reveal what kinds of muscle actions are important in crying and laughter in order to work on providing more detailed features in facial animations, while maintaining real-time execution.