- Number
- 9892539
- Published
- 2018-02-13
- Filed
- 2013-10-18
- Assignee
- DISNEY ENTERPRISES, INC.
- Inventors
- Thomaszewski; Bernhard; Sumner; Robert; Hahn; Fabian; Coros; Stelian; Gross; Markus; Martin; Sebastian
- CPC
- G06T13/20; G06T13/00; G06T13/40
- Verdict
- Medium Notable software
- Source
- Google Patents · FreePatentsOnline
The keeper's note
Rig-based physics simulation.
Abstract
A method is disclosed for applying physics-based simulation to an animator provided rig. The disclosure presents equations of motions for simulations performed in the subspace of deformations defined by an animator's rig. The method receives an input rig with a plurality of deformation parameters, and the dynamics of the character are simulated in the subspace of deformations described by the character's rig. Stiffness values defined on rig parameters are transformed to a non-homogeneous distribution of material parameters for the underlying rig.
Background
TECHNICAL FIELD(1) The present disclosure relates generally to computer animation, and, more particularly, to a method for performing physics-based simulations on an animator's rig.DESCRIPTION OF THE RELATED ART(2) Character animation is a vital component of contemporary computer games and film productions. Deformation is encoded in the rigging stage when artists carefully design the character's range of meaningful deformations in terms of a low-dimensional set of intuitive control parameters. The character's movement is determined during the animation phase, when animators set values for the control parameters over time in order to bring the character to life and make it act.BRIEF SUMMARY OF THE DISCLOSURE(3) A method is disclosed that brings the benefits of physics-based simulations to traditional animation pipelines. Equations of motion are formulated in the subspace of deformations defined by an animator's rig. The framework fits into the workflow typically employed by artists, as the output consists of animation curves that are identical in nature to the result of manual key framing. Artists are therefore capable of exploring the full spectrum between hand-crafted animation and unrestricted physical simulation. To enhance the artist's control, a method is provided that transforms stiffness values defined on rig parameters to a non-homogeneous distribution of material parameters for the underlying finite element method (FEM) model. In addition, automatically extracted hig
Claims
1. A method, comprising: receiving an animation rig with a plurality of rig parameters, the rig parameters defining a deformation space for an attached surface mesh, the attached surface mesh comprising a plurality of nodes, the animation rig further comprising a volumetric mesh comprising a plurality of internal nodes and a correspondence set defining the connectivity among the plurality of internal nodes and a plurality of surface vertices of the attached surface mesh; receiving material stiffness data on a subset of the rig parameters, the material stiffness data defining a stiffness scale value for each of the subset of the rig parameters, wherein the stiffness scale value is relative to a stiffness of a homogeneous material chosen for a finite element method model derived from the attached surface mesh; using the volumetric mesh to compute internal deformations and corresponding elastic energies; using the rig and the material stiffness data to influence a physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions, wherein the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions is constrained by the deformation space of the rig; and generating a plurality of keyframes on some or all of the parameters as a result of the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions; wherein the physics-based simulation comprises eliminating one or more of the plurality of surface vertices from the correspondence set such that a plurality of degrees of freedom required to compute the physics-based simulation are reduced to the subset of the rig parameters.
10. A non-transitory computer readable medium comprising an instruction set configured to cause a computing device to perform: receiving an animation rig with a plurality of rig parameters, the rig parameters defining a deformation space for an attached surface mesh, the attached surface mesh comprising a plurality of nodes, the animation rig further comprising a volumetric mesh comprising a plurality of internal nodes and a correspondence set defining the connectivity among the plurality of internal nodes and a plurality of surface vertices of the attached surface mesh; receiving material stiffness data on a subset of the rig parameters, the material stiffness data defining a stiffness scale value for each of the subset of the rig parameters, wherein the stiffness scale value is relative to a stiffness of a homogeneous material chosen for a finite element method model derived from the attached surface mesh; using the volumetric mesh to compute internal deformations and corresponding elastic energies; using the rig and the material stiffness data to influence a physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions, wherein the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions is constrained by the deformation space of the rig; and generating a plurality of keyframes on some or all of the rig parameters as a result of the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions; wherein the physics-based simulation comprises eliminating one or more of the plurality of surface vertices from the correspondence set such that a plurality of degrees of freedom required to compute the physics-based simulation are reduced to the subset of the rig parameters.