Scene-based Foveated Fluid Animation in Virtual Reality.

Physically-based fluid animation in Virtual Reality (VR) significantly enhances the user experience through visually engaging flow motions. Nonetheless, such simulations are often limited by their substantial computational demands. A tailored adaptive simulation algorithm is important for high-performance VR fluid simulations, which dynamically allocate degrees of freedom (DoF) while accounting for user perception in VR. This paper proposes a novel scene-based gaze-contingent fluid simulation system for VR, featuring a highly adaptive fluid simulator integrated with a VR perceptual model that accounts for the foveation and geometry of fluid. Our method leverages an eccentricity and curvature-dependent perceptual model to dynamically allocate computational resources, improving the efficiency and maintaining spatio-temporal stability of fluid animation in VR. A user study was conducted to measure the simulation resolution thresholds for fluid animations in VR, considering various levels of eccentricity and curvature. Our findings indicate notable differences in perceptual thresholds based on these metrics. By incorporating these insights into our adaptive fluid simulator as a unified sizing function, we maintain perceptually optimal particle resolution, achieving up to a 3.62× performance improvement while delivering superior perceptual realism and user experience, as validated by a subjective evaluation study.