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.

Additional Metadata
Keywords Fluid simulation, Meniscus, Shallow water, Surface optimization, Virtual pipes, Viscosity
Persistent URL dx.doi.org/10.1016/j.cag.2018.08.005
Journal Computers and Graphics (Pergamon)
Citation
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