39-Issue 8

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https://diglib.eg.org/handle/10.2312/2632936

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Browsing 39-Issue 8 by Subject "Applied computing"

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    A Hybrid Lagrangian/Eulerian Collocated Velocity Advection and Projection Method for Fluid Simulation
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Gagniere, Steven; Hyde, David; Marquez-Razon, Alan; Jiang, Chenfanfu; Ge, Ziheng; Han, Xuchen; Guo, Qi; Teran, Joseph; Bender, Jan and Popa, Tiberiu
    We present a hybrid particle/grid approach for simulating incompressible fluids on collocated velocity grids. Our approach supports both particle-based Lagrangian advection in very detailed regions of the flow and efficient Eulerian grid-based advection in other regions of the flow. A novel Backward Semi-Lagrangian method is derived to improve accuracy of grid based advection. Our approach utilizes the implicit formula associated with solutions of the inviscid Burgers' equation. We solve this equation using Newton's method enabled by C1 continuous grid interpolation. We enforce incompressibility over collocated, rather than staggered grids. Our projection technique is variational and designed for B-spline interpolation over regular grids where multiquadratic interpolation is used for velocity and multilinear interpolation for pressure. Despite our use of regular grids, we extend the variational technique to allow for cut-cell definition of irregular flow domains for both Dirichlet and free surface boundary conditions.
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    Interactive Sound Propagation For Dynamic Scenes Using 2d Wave Simulation
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Rosen, Matthew; Godin, Keith W.; Raghuvanshi, Nikunj; Bender, Jan and Popa, Tiberiu
    We present a technique to model wave-based sound propagation to complement visual animation in fully dynamic scenes. We employ 2D wave simulation that captures geometry-based diffraction effects such as obstruction, reverberation, and directivity of perceptually-salient initial sound at the source and listener. We show real-time performance on a single CPU core on modestly-sized scenes that are nevertheless topologically complex. Our key ideas are to exploit reciprocity and use a perceptual encoding and rendering framework. These allow the use of low-frequency finite-difference simulations on static scene snapshots. Our results show plausible audio variation that remains robust to motion and geometry changes. We suggest that wave solvers can be a practical approach to real-time dynamic acoustics. We share the complete C++ code of our ''Planeverb'' system.