Rig-based physics simulation

Patent metadata

Field	Value
Publication number	US-9659397-B2
Application number	US-201313843856-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Jan 11, 2013
Publication date	May 23, 2017
Grant date	May 23, 2017

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. In certain embodiments, the present disclosure provides a method that transforms stiffness values defined on rig parameters to a non-homogeneous distribution of material parameters for the underlying rig.

First claim

The invention claimed is:

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;
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 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 on the subset of the rig parameters, 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 for some or all of the rig parameters of the animation rig as a result of the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions on the subset of the rig parameters.

2. The method of claim 1 , further comprising analyzing the simulation to create a set of high-level rig parameters, each high-level rig parameter being a combination of two or more of the rig parameters.

3. The method of claim 2 , further comprising using one or more of the high-level rig parameters to influence a second physics-based simulation; and
generating keyframes on the animation rig as a result of the second simulation.

4. The method of claim 1 , further comprising using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig.

5. The method of claim 4 , wherein the rig parameters can be used to calculate an elastic energy, and
further wherein, using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig comprises
receiving position values for a subset of the surface mesh nodes, and
calculating the remaining surface mesh node position values such that the elastic energy in the deformation space is substantially minimized.

6. 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;
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;
performing a physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions on the subset of the rig parameters, wherein the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions is constrained by the deformation space; and
generating a plurality of keyframes for the rig based on the results of the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions on the subset of the rig parameters.

7. The method of claim 6 further comprising receiving material stiffness data relating to the parameters,
wherein the simulation is both constrained by the deformation space and influenced by the material stiffness data.

8. The method of claim 7 , further comprising analyzing the simulation to create a set of high-level rig parameters, each high-level rig parameter being a combination of two or more of the rig parameters.

9. The method of claim 8 , further comprising using one or more of the high-level rig parameters to influence a second physics-based simulation; and
generating keyframes on the animation rig as a result of the second simulation.

10. The method of claim 6 , further comprising using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig.

11. The method of claim 10 , wherein the rig parameters can be used to calculate an elastic energy, and
further wherein, using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig comprises
receiving position values for a subset of the surface mesh nodes, and
calculating the remaining surface mesh node position values such that the elastic energy in the deformation space is substantially minimized.

12. 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;
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 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 on the subset of the rig parameters, 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 for some or all of the rig parameters of the animation rig as a result of the physics-based simulation of the effects of one or more of gravity, inertia, and penalty-collisions on the subset of the rig parameters.

13. The non-transitory computer readable medium of claim 12 , wherein the instruction set is further configured to cause a computing device to perform analyzing the simulation to create a set of high-level rig parameters, each high-level rig parameter being a combination of two or more of the rig parameters.

14. The non-transitory computer readable medium of claim 13 , wherein the instruction set is further configured to cause a computing device to perform:
using one or more of the high-level rig parameters to influence a second physics-based simulation; and
generating keyframes on the animation rig as a result of the second simulation.

15. The non-transitory computer readable medium of claim 12 , wherein the instruction set is further configured to cause a computing device to perform using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig.

16. The non-transitory computer readable medium of claim 15 , wherein the rig parameters can be used to calculate an elastic energy, and
further wherein, using one or more of the rig parameters to perform inverse kinematics calculations on the animation rig comprises
receiving position values for a subset of the surface mesh nodes, and
calculating the remaining surface mesh node position values such that the elastic energy in the deformation space is substantially minimized.

17. A non-transitory computer readable medium comprising an instruction set configured to cause a computer 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;
receiving mater

Assignees

• Disney Entpr Inc

Inventors

• Sumner Robert
• Hahn Fabian
• Coros Stelian
• Thomaszewski Bernhard
• Martin Sebastian
• Gross Markus

Classifications

• G06T13/40 Primary

  of characters, e.g. humans, animals or virtual beings · CPC title