Mass Preserving Multi-Scale SPHPixar Technical Memo #13-04

We present a method for performing very high resolution, incompressible fluid simulations at multiple resolutions of detail, simultaneously. The particle-based method supports user-defined regions of refinement and can handle complex collision boundary conditions while remaining smooth and stable. Conservation of mass in refined detail levels is handled explicitly, overcoming mass-loss problems of previous multi-scale SPH techniques. By restricting fine-resolution particles to regions defined relatively near to the fluid surface and close to an observer, the computation time and storage requirements for large simulations are significantly reduced. Compared to an equivalent single-scale simulation, our method reduces the computational costs up to a factor of twelve. CR Categories: I.3.3 [Computer Graphics]: Three-Dimensional Graphics and Realism—Display Algorithms I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Radiosity;