Particle upsampling as a flexible post-processing approach to increase details in animations of splashing liquids

• Published in: Computers & graphics 2020-05, Vol.88, p.57-69
• Main Authors: Roy, Bruno, Paquette, Eric, Poulin, Pierre
• Format: Article
• Language: English
• Subjects: FLIP; Intersections; Liquids; Multi-resolution; Multi-scale; Post-processing; Post-processing approach; Procedural method; Splash modeling; Surface tension; Velocity distribution
• ISSN: 0097-8493; 1873-7684
• DOI: 10.1016/j.cag.2020.03.001

•Determine and upsample a splash volume for induced splash dynamics.•Special particles to infer surface tension behavior on upsampled particles.•Sparse implicit linear wave formulation to couple our model with input particles.•Offer a trade-off between realistic and artistic splash effects.•Following pre-computation steps, allow interactive splash editing. [Display omitted] Realistic and detailed liquid splashes require costly fine-scale discretization. We present an efficient post-processing approach for particle-based methods to locally improve the behavior of splashes on coarser liquids. Our method first computes a splash volume over time from the intersections between an identified upsampling volume and colliding volumes. We then upsample particles inside cells of the splash volume; these cells are pre-computed using a likelihood score based on criteria favoring emerging particles. In addition to the advection scheme, enhanced realism is achieved by applying a localized artificial pressure on upsampled particles in order to mimic surface tension in critical regions of splashes. Finally, we propagate waves using a novel implicit model that couples the impact of upsampled particles on the coarser liquid by updating the velocity field at these locations. Our implicit wave model can produce detailed swirls by solely applying velocity updates directly on the underlying particles from the coarse liquid, and prevents from using a high density of surface points. As a result, our approach can generate localized and parameterizable high-resolution splashes from solid-liquid and liquid-liquid interactions, and thus can simulate a wide range of unique and customizable splashes on top of an animated coarse liquid.