A Semi-Implicit Material Point Method for the Continuum Simulation of Granular Materials

Gilles Daviet, Florence Bertails-Descoubes We present a new continuum-based method for the realistic simulation of large-scale free-flowing granular materials. We derive a compact model for the rheology of the material, which accounts for the exact nonsmooth Drucker-Prager yield criterion combined with a varying volume fraction. Thanks to a semi-implicit timestepping scheme and a careful spatial […]

Surface-Only Liquids

Fang Da, David Hahn, Christopher Batty, Chris Wojtan, Eitan Grinspun We propose a novel surface-only technique for simulating incompressible, inviscid and uniform-density liquids with surface tension in three dimensions. The liquid surface is captured by a triangle mesh on which a Lagrangian velocity field is stored. Because advection of the velocity field may violate the […]

Drucker-Prager Elastoplasticity for Sand Animation

Gergely Klar, Theodore Gast, Andre Pradhana, Chuyuan Fu, Craig Schroeder, Chenfanfu Jiang, Joseph Teran We simulate sand dynamics using an elastoplastic, continuum assumption. We demonstrate that the Drucker-Prager plastic flow model combined with a Hencky-strain-based hyperelasticity accurately recreates a wide range of visual sand phenomena with moderate computational expense. We use the Material Point Method […]

Resolving Fluid Boundary Layers with Particle Strength Exchange and Weak Adaptivity

Xinxin Zhang, Minchen Li, Robert Bridson Most fluid scenarios in graphics have a high Reynolds number, where viscosity is dominated by inertial effects, thus most solvers drop viscosity altogether: numerical damping from coarse grids is generally stronger than physical viscosity while resembling it in character. However, viscosity remains crucial near solid boundaries, in the boundary […]

Ebb: A DSL for Physical Simulation on CPUs and GPUs

Gilbert Bernstein, Chinmayee Shah, Crystal Lemire, Zachery DeVito, Matthew Fisher, Philip Levis, Pat Hanrahan Designing programming environments for physical simulation is challenging because simulations rely on diverse algorithms and geometric domains. These challenges are compounded when we try to run efficiently on heterogeneous parallel architectures. We present Ebb, a domain-specific language (DSL) for simulation, that […]

Liquid boundaries for implicit incompressible SPH

Jens Cornelis, Markus Ihmsen, Andreas Peer, Matthias Teschner We propose a novel unified particle representation for fluids and solid boundaries in Implicit Incompressible SPH (IISPH). In contrast to existing particle representations, the proposed concept does not require a separate processing of fluid and boundary particles. On one hand, this results in a simplified solver implementation […]

A Practical Method for High-Resolution Embedded Liquid Surfaces

Ryan Goldade, Christopher Batty, Chris Wojtan Combining high-resolution level set surface tracking with lower resolution physics is an inexpensive method for achieving highly detailed liquid animations. Unfortunately, the inherent resolution mismatch introduces several types of disturbing visual artifacts. We identify the primary sources of these artifacts and present simple, efficient, and practical solutions to address […]

Narrow Band FLIP for Liquid Simulations

Florian Ferstl, Ryoichi Ando, Chris Wojtan, Rudiger Westermann, Nils Thuerey The Fluid Implicit Particle method (FLIP) for liquid simulations uses particles to reduce numerical dissipation and provide important visual cues for events like complex splashes and small-scale features near the liquid surface. Unfortunately, FLIP simulations can be computationally expensive, because they require a dense sampling […]

Solving the Fluid Pressure Poisson Equation Using Multigrid—Evaluation and Improvements

Christian Dick, Marcus Rogowsky, Rüdiger Westermann In many numerical simulations of fluids governed by the incompressible Navier-Stokes equations, the pressure Poisson equation needs to be solved to enforce mass conservation. Multigrid solvers show excellent convergence in simple scenarios, yet they can converge slowly in domains where physically separated regions are combined at coarser scales. Moreover, […]

Implicit Incompressible SPH on the GPU

Prashant Goswami, André Eliasson, Pontus Franzén This paper presents CUDA-based parallelization of implicit incompressible SPH (IISPH) on the GPU. Along with the detailed exposition of our implementation, we analyze various components involved for their costs. We show that our CUDA version achieves near linear scaling with the number of particles and is faster than the […]