- Number
- 10733336
- Published
- 2020-08-04
- Filed
- 2016-01-15
- Assignee
- Disney Enterprises, Inc.
- Inventors
- Stomakhin; Alexey, Setaluri; Rajsekhar
- CPC
- G06F30/20
- Verdict
- Low Notable software
- Source
- Google Patents · FreePatentsOnline
The keeper's note
Adaptive material-point-method physics simulation (VFX).
Abstract
An adaptive material point method for simulating and rendering of solid materials is disclosed. During each time step, a simulation application splits and/or merges particles according to a resolution of a grid and assigns properties to the split/merged particles. The simulation application then rasterizes particle information, including masses and velocities, to the grid, on which forces and/or collisions are computed to obtain updated velocities. Grid information, including the updated velocities, is then transferred back to the particles. The transfer from particles to grid and back from grid to particles may employ different transfer functions. In particular, a quadratic transfer function may be used to transfer information from the particles to the grid, while a linear transfer function may be used elsewhere, including to transfer information back from the grid to the particles. After updated velocities are transferred to the particles, the simulation application advects the particles using the updated velocities.
Background
BACKGROUNDField of the Invention(1) This disclosure provides techniques for computer simulation and rendering of physical phenomena. More specifically, one aspect of this disclosure presents an adaptive material point method for computer simulation and rendering of solids.Description of the Related Art(2) Hybrid Lagrangian/Eulerian methods, in which particle and grid formulations are used in conjunction to simulate materials undergoing deformations, are commonplace in computer graphics simulations. The Material Point Method (MPM) is one such hybrid Lagrangian/Eulerian method, and the MPM has recently become a popular physically-based simulation tool in computer graphics and the movie effects industry, due to its ability to produce high fidelity visual results for wide ranges of materials properties. However, the high computational cost associated with MPM has limited its use.SUMMARY(3) One aspect of this disclosure provides a computer-implemented method of simulating a system. The method generally includes, for one or more iterations: transferring, via a first transfer function, information characterizing masses and initial velocities of particles in the system from the particles to a grid; computing forces and/or collision responses on the grid, using a second transfer function, to obtain updated velocities; transferring, via the second transfer function, the updated velocities from the grid to the particles; and advecting the particles based on the updated velocities(4) Fur
Claims
1. A computer-implemented method of reducing a computational overhead in simulating and rendering deformable solid materials, the computer-implemented method comprising, for one or more iterations: dynamically updating a topology of a grid in order to reflect a current geometric state of a simulation of a solid material being deformed over time, including decreasing a specified resolution for one or more non-surface regions of the solid material, the solid material having particles, each particle having a rasterization radius, wherein the grid having the updated topology comprises a non-uniform grid, which has a non-uniform resolution; merging, based on the decreased resolution, two or more particles in the one or more non-surface regions of the solid material into one or more larger particles relative to the two or more particles; rasterizing particle properties characterizing masses and initial velocities of the particles of the solid material, including the merged particles, by transferring, via a first transfer function, the particle properties from the particles to the non-uniform grid based on the rasterization radii of the particles; computing at least one of forces and collision responses on the non-uniform grid by operation of one or more computer processors in order to obtain updated velocities, wherein the updated velocities are transferred from the non-uniform grid back to the particles of the solid material via a second transfer function different from the first transfer function, wherein the second transfer function is determined based on a compatibility constraint associated with the non-uniform grid; and subsequent to advecting the particles of the solid material based on the updated velocities, rendering one or more images based at least in part on the advected particles, wherein a computational overhead of the simulation is reduced based on the merged particles, wherein the one or more images are output for display.
15. A non-transitory computer-readable medium storing a program executable to perform operations for reducing a computational overhead in simulating and rendering deformable solid materials, the operations comprising, for one or more iterations: dynamically updating a topology of a grid in order to reflect a current geometric state of a simulation of a solid material being deformed over time, including decreasing a specified resolution for one or more non-surface regions of the solid material, the solid material having particles, each particle having a rasterization radius, wherein the grid having the updated topology comprises a non-uniform grid, which has a non-uniform resolution; merging, based on the decreased resolution, two or more particles in the one or more non-surface regions of the solid material into one or more larger particles relative to the two or more particles; rasterizing particle properties characterizing masses and initial velocities of the particles of the solid material, including the merged particles, by transferring, via a first transfer function, the particle properties from the particles to the non-uniform grid based on the rasterization radii of the particles; computing at least one of forces and collision responses on the non-uniform grid by operation of one or more computer processors when executing the program, in order to obtain updated velocities, wherein the updated velocities are transferred from the non-uniform grid back to the particles of the solid material via a second transfer function different from the first transfer function, wherein the second transfer function is determined based on a compatibility constraint associated with the non-uniform grid; and subsequent to advecting the particles of the solid material based on the updated velocities, rendering one or more images based at least in part on the advected particles, wherein a computational overhead of the simulation is reduced based on the merged particles, wherein the one or more images are output for display.
22. A system of reducing a computational overhead in simulating and rendering deformable solid materials, the system comprising: one or more computer processors; and a memory including a program executable by the one or more computer processors to perform operations comprising, for one or more iterations: dynamically updating a topology of a grid in order to reflect a current geometric state of a simulation of a solid material being deformed over time, including decreasing a specified resolution for one or more non-surface regions of the solid material, the solid material having particles, each particle having a rasterization radius, wherein the grid having the updated topology comprises a non-uniform grid, which has a non-uniform resolution; merging, based on the decreased resolution, two or more particles in the one or more non-surface regions of the solid material into one or more larger particles relative to the two or more particles; rasterizing particle properties characterizing masses and initial velocities of the particles of the solid material, including the merged particles, by transferring, via a first transfer function, the particle properties from the particles to the non-uniform grid based on the rasterization radii of the particles; computing at least one of forces and collision responses on the non-uniform grid in order to obtain updated velocities, wherein the updated velocities are transferred from the non-uniform grid back to the particles of the solid material via a second transfer function different from the first transfer function, wherein the second transfer function is determined based on a compatibility constraint associated with the non-uniform grid; and subsequent to advecting the particles based on the updated velocities, rendering one or more images based at least in part on the advected particles, wherein a computational overhead of the simulation is reduced based on the merged particles, wherein the one or more images are output for display.