- Number
- 10210287
- Published
- 2019-02-19
- Filed
- 2014-07-03
- Assignee
- Disney Enterprises, Inc.
- Inventors
- Selle; Andrew, Teran; Joseph, Stomakhin; Alexey
- CPC
- G06F30/20
- Verdict
- Medium Notable software
- Source
- Google Patents · FreePatentsOnline
The keeper's note
Augmented material point method simulating phase changes/materials.
Abstract
The disclosure provides an approach for simulating and rendering materials across different states and undergoing phase transitions. In one configuration, a simulation application generates video frames depicting a material phenomenon using an augmented material point method (MPM). Traditional MPM does not handle incompressible materials such as fluids. Techniques disclosed herein augment the MPM with a Chorin-style projection technique to enable simulation of arbitrarily incompressible materials. In one configuration, this is achieved with a marker-and-cell (MAC) grid based MPM solver, a splitting of stress used in the simulation into elastic and dilational parts, a projection-like implicit treatment of the Eulerian evolution of the dilational part of the stress, and particular techniques for rasterizing and updating quantities on the MAC grid. In addition, a heat model may be coupled to the MPM solver, allowing material changes to be driven with temperature and phase changes.
Background
BACKGROUND(1) Field(2) This disclosure provides techniques for simulating and rendering materials in computer animation.(3) Description of the Related Art(4) In computer animation physics engines, “solvers” are used to simulate physical behavior of objects (e.g., the physical response of an object to a collision with another object). These solvers typically employ numerical techniques to approximate the physics so that simulations can be efficiently performed on a computer. Specialized solvers have been used to simulate a variety of phenomena in graphics and computational physics. Such solvers include fluid simulators, rigid body simulators, and cloth simulators, among others, each of which is suited to simulate behavior of a particular type of material. For example, fluid simulators are suited for simulating liquids which deform with no memory, while rigid body simulators are suited for simulating destruction and debris where there is no deformation (e.g., glass shattering).(5) Such traditional simulators have difficulty simulating materials across different states and undergoing phase transitions, such as ice melting into water, lava solidifying into pāhoehoe, butter melting in a pan, and the like. The difficulty lies in achieving robust, accurate, and efficient simulation of a wide variety of material behaviors without requiring overly complex implementations. Explicit coupling between solid and fluid solvers has been proposed, but such coupling typically requires complex
Claims
1. A computer-implemented method for simulating and rendering a material while avoiding material point method locking, comprising: for each of a plurality of time steps of a simulation of the material undergoing a phase transition between two states of the material: transferring states of particles representing the material to a grid, determining intermediate grid velocities using a material point method computation, wherein the material point method computation discretizes deviatoric forces, including shear forces, that affect the material using a deviatoric component of a constitutive model, the constitutive model dictating forces that affect the material and splitting into the deviatoric component and a dilational component, applying a projection over the grid, wherein applying the projection includes solving for pressure and correcting the intermediate grid velocities to projected grid velocities using the pressure, and wherein the projection discretizes dilational forces, including at least one of mean volumetric and spherical forces, that affect the material using the dilational component of the constitutive model, and updating the states of one or more of the particles based on at least the projected grid velocities; and rendering one or more images depicting the material using at least the updated states of the one or more of the particles at the plurality of time steps.
10. A non-transitory computer-readable storage medium storing a program, which, when executed by a processor performs operations for simulating and rendering a material while avoiding material point method locking, the operations comprising: for each of a plurality of time steps of a simulation of the material undergoing a phase transition between two states of the material: transferring states of particles representing the material to a grid, determining intermediate grid velocities using a material point method computation, wherein the material point method computation discretizes deviatoric forces, including shear forces, that affect the material using a deviatoric component of a constitutive model, the constitutive model dictating forces that affect the material and splitting into the deviatoric component and a dilational component, applying a projection over the grid, wherein applying the projection includes solving for pressure and correcting the intermediate grid velocities to projected grid velocities using the pressure, and wherein the projection discretizes dilational forces, including at least one of mean volumetric and spherical forces, that affect the material using the dilational component of the constitutive model, and updating the states of one or more of the particles based on at least the projected grid velocities; and rendering one or more images depicting the material using at least the updated states of the one or more of the particles at the plurality of time steps.
18. A system, comprising: a processor; and a memory, wherein the memory includes an application program configured to perform operations for simulating and rendering a material while avoiding material point method locking, the operations comprising: for each of a plurality of time steps of a simulation of the material undergoing a phase transition between two states of the material: transferring states of particles representing the material to a grid, determining intermediate grid velocities using a material point method computation, wherein the material point method computation discretizes deviatoric forces, including shear forces, that affect the material using a deviatoric component of a constitutive model, the constitutive model dictating forces that affect the material and splitting into the deviatoric component and a dilational component; applying a projection over the grid, wherein applying the projection includes solving for pressure and correcting the intermediate grid velocities to projected grid velocities using the pressure, and wherein the projection discretizes dilational forces, including at least one of mean volumetric and spherical forces, that affect the material using the dilational component of the constitutive model; and updating the states of one or more of the particles based on at least the projected grid velocities, and rendering one or more images depicting the material using at least the updated states of the one or more of the particles at the plurality of time steps.