We propose an approach for real-time shallow water simulation, building upon the virtual pipes model with multi-layered heightmaps. Our approach introduces the use of extended pipes that are capable of resolving flows through fully flooded passages, which is not possible using current multi-layered techniques. We extend the virtual pipe method with a physically-based viscosity model that is both fast and stable. Our viscosity model is integrated implicitly without the expense of solving a large linear system. Despite the few simplifications necessary to achieve a real-time viscosity model, we show that our new viscosity model produces results that match the behavior of an offline fluid-implicit particle (FLIP) simulation for various viscosity values. The liquid is rendered as a triangular mesh surface built from a heightmap. We propose a novel surface optimization approach that prevents interpenetrations of the liquid surface with the underlying terrain geometry. To improve the realism of small-scale scenarios, we present a meniscus shading approach with a view-dependent adjustment of the liquid surface normals based on a distance field. Our implementation runs in real time on various scenarios of roughly 10 × 10 cm at a resolution of 0.5 mm, with up to five layers.

Fluid simulation, Meniscus, Shallow water, Surface optimization, Virtual pipes, Viscosity
Computers and Graphics (Pergamon)
School of Computer Science

Dagenais, F. (François), Vervondel, V. (Valentin), Guzmán, J.E. (Julián E.), Hay, A. (Alexander), Delorme, S. (Sébastien), Mould, D, & Paquette, E. (Eric). (2018). Extended virtual pipes for the stable and real-time simulation of small-scale shallow water. Computers and Graphics (Pergamon), 76, 84–95. doi:10.1016/j.cag.2018.08.005