Character articulation through profile curves

Patent metadata

Field	Value
Publication number	US-12450835-B2
Application number	US-202218067380-A
Country	US
Kind code	B2
Filing date	Dec 16, 2022
Priority date	Dec 16, 2022
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

Techniques for computer animation are disclosed. These techniques include receiving a plurality of curvenet segments relating to a computer animation model comprising a surface mesh, and generating a cut-mesh that cuts the surface mesh using the curvenet segments. The techniques further include computing a deformation of the plurality of curvenet segments to the surface mesh using the cut-mesh, and displaying the computer animation model in a pose based on the deformation.

First claim

What is claimed is:

1. A method, comprising:
receiving a plurality of curvenet segments relating to a computer animation model comprising a surface mesh, wherein the plurality of curvenet segments are detached from the surface mesh and agnostic to connectivity and topology of the surface mesh, and wherein receiving the plurality of curvenet segments comprises:
identifying a set of control points located on a surface of the surface mesh; and
receiving splines connecting the set of control points and generated based, in part, on profiles of the surface mesh;

generating a cut-mesh that splits one or more polygons of the surface mesh that are crossed by at least one of the plurality of curvenet segments into a set of sub-polygons of the surface mesh;
computing a deformation of the plurality of curvenet segments to the surface mesh using the cut-mesh; and
displaying the computer animation model in a pose based on the deformation.

2. The method of claim 1 , wherein computing the deformation of the plurality of curvenet segments to the surface mesh further comprises:
estimating a respective deformation gradient matrix for each side of each of the plurality of curvenet segments.

3. The method of claim 2 , wherein each respective deformation gradient matrix quantifies an amount of at least one of: (i) rotation or (ii) stretching relating to deforming a rest segment for the computer animation model to a corresponding posed segment in the pose.

4. The method of claim 1 , wherein generating the cut-mesh comprises:
projecting a plurality of samples, relating to the plurality of curvenet segments, to the surface mesh;
incorporating the plurality of curvenet segments into the cut-mesh; and
updating the cut-mesh connectivity.

5. The method of claim 1 , further comprising:
discretizing the generated cut mesh using a plurality of matrices.

6. The method of claim 5 , wherein the plurality of matrices comprise a Laplacian matrix, the method further comprising:
factorizing the Laplacian matrix.

7. The method of claim 1 , further comprising:
rearranging one or more deformation gradients into a constraint matrix;
solving for deformation gradients at vertices relating to the surface mesh;
computing a first matrix relating to deformed cut-face polygons and a second matrix relating to displaced curvenet samples; and
solving for deformed vertex positions.

8. The method of claim 1 , wherein displaying the computer animation model in the pose is based on a hybrid rigging approach that includes both the plurality of curvenet segments and additional surface deformations.

9. The method of claim 1 , wherein the displaying the computer animation model in the pose is further based on a plurality of blend shapes.

10. The method of claim 1 ,
wherein the plurality of curvenet segments relate to a plurality of Bézier splines created by a user,
wherein the cut-mesh is pre-computed, prior to a runtime, and stored in an electronic repository, and
wherein computing the deformation occurs during the runtime and comprises retrieving the cut-mesh from the electronic repository.

11. A non-transitory computer-readable medium containing computer program code that, when executed by operation of one or more computer processors, performs operations comprising:
receiving a plurality of curvenet segments relating to a computer animation model comprising a surface mesh, wherein the plurality of curvenet segments are detached from the surface mesh and agnostic to connectivity and topology of the surface mesh, and wherein receiving the plurality of curvenet segments comprises:
identifying a set of control points located on a surface of the surface mesh; and
receiving splines connecting the set of control points and generated based, in part, on profiles of the surface mesh;

generating a cut-mesh that splits one or more polygons of the surface mesh that are crossed by at least one of the plurality of curvenet segments into a set of sub-polygons of the surface mesh;
computing a deformation of the plurality of curvenet segments to the surface mesh using the cut-mesh; and
displaying the computer animation model in a pose based on the deformation.

12. The non-transitory computer-readable medium of claim 11 , wherein computing the deformation of the plurality of curvenet segments to the surface mesh further comprises:
estimating a respective deformation gradient matrix for each side of each of the plurality of curvenet segments.

13. The non-transitory computer-readable medium of claim 12 , wherein each respective deformation gradient matrix quantifies an amount of at least one of: (i) rotation or (ii) stretching relating to deforming a rest segment for the computer animation model to a corresponding posed segment in the pose.

14. The non-transitory computer-readable medium of claim 11 , wherein generating the cut-mesh comprises:
projecting a plurality of samples, relating to the plurality of curvenet segments, to the surface mesh;
incorporating the plurality of curvenet segments into the cut-mesh; and
updating the cut-mesh connectivity.

15. The non-transitory computer-readable medium of claim 11 , the operations further comprising:
discretizing the generated cut mesh using a plurality of matrices, the plurality of matrices comprising a Laplacian matrix; and
factorizing the Laplacian matrix.

16. A system, comprising:
a processor; and
a memory having instructions stored thereon which, when executed on the processor, performs operations comprising:
receiving a plurality of curvenet segments relating to a computer animation model comprising a surface mesh, wherein the plurality of curvenet segments are detached from the surface mesh and agnostic to connectivity and topology of the surface mesh, and wherein receiving the plurality of curvenet segments comprises:
identifying a set of control points located on a surface of the surface mesh; and
receiving splines connecting the set of control points and generated based, in part, on profiles of the surface mesh;

generating a cut-mesh that splits one or more polygons of the surface mesh that are crossed by at least one of the plurality of curvenet segments into a set of sub-polygons of the surface mesh;
computing a deformation of the plurality of curvenet segments to the surface mesh using the cut-mesh; and
displaying the computer animation model in a pose based on the deformation.

17. The system of claim 16 , wherein computing the deformation of the plurality of curvenet segments to the surface mesh further comprises:
estimating a respective deformation gradient matrix for each side of each of the plurality of curvenet segments.

18. The system of claim 17 , wherein each respective deformation gradient matrix quantifies an amount of at least one of: (i) rotation or (ii) stretching relating to deforming a rest segment for the computer animation model to a corresponding posed segment in the pose.

19. The system of claim 16 , wherein generating the cut-mesh comprises:
projecting a plurality of samples, relating to the plurality of curvenet segments, to the surface mesh;
incorporating the plurality of curvenet segments into the cut-mesh; and
updating the cut-mesh connectivity.

20. The system of claim 16 , the operations further comprising:
discretizing the generated cut mesh using a plurality of matrices, the plurality of matrices comprising a Laplacian matrix; and
factorizing the Laplacian matrix.

Assignees

• Pixar

Inventors

• De Goes Fernando Ferrari
• Fleischer Kurt W
• Sheffler William F

Classifications

• G06T13/40 Primary

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

• G06T19/20

  Editing of three-dimensional [3D] images, e.g. changing shapes or colours, aligning objects or positioning parts · CPC title

• G06T2219/2016

  Rotation, translation, scaling · CPC title

• G06T17/205 Primary

  Re-meshing · CPC title