Robust attribute transfer for character animation

• US 20170032560A1
• Filed: 07/21/2016
• Published: 02/02/2017
• Est. Priority Date: 07/27/2015
• Status: Active Grant

• Current Assignee: Autodesk, Inc.
• Original Assignee: Autodesk, Inc.
• Inventors: Dionne, Olivier, De Lasa, Martin, Ramachandran, Srinivasan, Fallhdoust, Sahel, Paquette, Eric, Ghafourzadeh, Donya, Avril, Quentin
• Granted Patent: US 10,489,956 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 13/40 of characters, e.g. humans, animals or virtual beings
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation
• CPC Class Codes: G06T 19/20 Editing of 3D images, e.g. changing shapes or colours, aligning objects or positioning parts
• CPC Class Codes: G06T 2219/2016 Rotation, translation, scaling

Abstract

One embodiment of the invention disclosed herein provides techniques for transferring attributes from a source animated character to a target character. A character attribute transfer system identifies a first set of markers corresponding to the source animated character. The character attribute transfer system identifies a second set of markers corresponding to the target character. The character attribute transfer system generates a geometric correspondence between the source animated character and the target character based on the first set of markers and the second set of markers independent of differences in geometry between the source animated character and the target character. The character attribute transfer system transfers a first attribute from the source animated character to the target character based on the geometric correspondence.

Claims

1. A method for transferring attributes from a source animated character to a target character, comprising:

identifying a first set of markers corresponding to the source animated character;

identifying a second set of markers corresponding to the target character;

generating a geometric correspondence between the source animated character and the target character based on the first set of markers and the second set of markers independent of differences in geometry between the source animated character and the target character; and

transferring a first attribute from the source animated character to the target character based on the geometric correspondence.

2. The method of claim 1, wherein the first attribute comprises a joint hierarchy, and further comprising performing a pose normalization process on the source animated character to align a first joint hierarchy associated with the source animated character with a second joint hierarchy associated with the source animated character.

3. The method of claim 1, wherein the first attribute comprises a joint hierarchy, and further comprising:

determining a first location of a first joint included in a first joint hierarchy associated with the source animated character; and

computing a second location at which to place the first joint within a second joint hierarchy associated with the target character.

4. The method of claim 1, wherein the first attribute comprises a joint hierarchy, and further comprising:

determining a first rotation angle of a first joint included in a first joint hierarchy associated with the source animated character; and

computing a second rotation angle for the first joint within a second joint hierarchy associated with the target character.

5. The method of claim 4, wherein the first attribute comprises a set of skinning weights, and further comprising:

computing a first skinning weight associated with a first mesh representation related to the target character based on one or more skinning weights associated with a second mesh representation related to the source animated character; and

attaching a first vertex included in the first mesh representation to a joint hierarchy associated with the target character based on the first skinning weight.

6. The method of claim 1, wherein the first attribute comprises a set of skinning weights, and further comprising:

determining that a first resolution of a first mesh representation associated with the source animated character is less than a second resolution of a second mesh representation associated with the target character;

performing a linear interpolation on a subset of skinning weights included in the set of skinning weights to generate a set of resampled source skinning weights; and

determining a first skinning weight associated with the target character based on the resampled skinning weights.

7. The method of claim 1, wherein the first attribute comprises a set of skinning weights, and further comprising:

determining that a first resolution of a first mesh representation associated with the target character is less than a second resolution of a second mesh representation associated with the source animated character;

selecting one or more vertices included in a first mesh representation associated with the source animated character;

applying a filter to a plurality of skinning weights associated with the one or more vertices to generated a filtered skinning weight; and

assigning the filtered skinning weight to a first vertex included in a second mesh representation associated with the target character.

8. The method of claim 1, wherein the first attribute comprises a set of skinning weights, and further comprising:

after transferring the first attribute to the target character, determining that a first skinning weight included in the set of skinning weights has changed; and

transferring the first skinning weight from the source animated character to the target character based on the geometric correspondence.

9. The method of claim 4, wherein the first attribute comprises a rig control that includes a set of controllers and one or more constraints that define how the source animated character can pose and move.

10. The method of claim 1, wherein the first attribute comprises a rig control and a set of (u, v) coordinates that defines positions of one or more textures that are projected onto a source mesh representation associated with the source animated character.

11. A non-transitory computer-readable storage medium including instructions that, when executed by a processor, cause the processor to transfer attributes from a source animated character to a target character by performing the steps of:

identifying a first set of markers corresponding to the source animated character;

identifying a second set of markers corresponding to the target character;

generating a geometric correspondence between the source animated character and the target character based on the first set of markers and the second set of markers independent of differences in geometry between the source animated character and the target character; and

transferring at least one of a joint hierarchy and a set of skinning weights from the source animated character to the target character based on the geometric correspondence.

12. The non-transitory computer-readable storage medium of claim 11, wherein the first attribute comprises a joint hierarchy, and further comprising performing a pose normalization process on the source animated character to align a first joint hierarchy associated with the source animated character with a second joint hierarchy associated with the source animated character.

13. The non-transitory computer-readable storage medium of claim 11, wherein the first attribute comprises a joint hierarchy, and further comprising:

determining a first location of a first joint included in a first joint hierarchy associated with the source animated character; and

computing a second location at which to place the first joint within a second joint hierarchy associated with the target character.

14. The non-transitory computer-readable storage medium of claim 11, wherein the first attribute comprises a joint hierarchy, and further comprising:

determining a first rotation angle of a first joint included in a first joint hierarchy associated with the source animated character; and

computing a second rotation angle for the first joint within a second joint hierarchy associated with the target character.

15. The non-transitory computer-readable storage medium of claim 11, wherein generating a geometric correspondence between the source animated character and the target character comprises deforming a source mesh representation associated with the source animated character to generate a deformed source mesh representation that matches a target mesh representation associated with the target character.

16. The non-transitory computer-readable storage medium of claim 15, wherein generating a geometric correspondence between the source animated character and the target character further comprises extracting a dense correspondence based on closest locations between the deformed source mesh representation and the target mesh representation.

17. The non-transitory computer-readable storage medium of claim 15, wherein each vertex included in the deformed source mesh representation is bijectively linked to a barycentric coordinate on a polygon of the target mesh representation.

18. The non-transitory computer-readable storage medium of claim 15, wherein each vertex included in the target mesh representation is bijectively linked to a barycentric coordinate on a polygon of the deformed source mesh representation.

19. A system, comprising:

a processor; and

a memory coupled to the processor and including a geometric correspondence engine and a transfer engine;

wherein, when executing the geometric correspondence engine, the processor is configured to;

identify a first set of markers placed on a source mesh representation associated with a source animated character,

identify a second set of markers placed on a target mesh representation associated with a target character, and

generate a geometric correspondence between the source animated character and the target character based on the first set of markers and the second set of markers independent of differences in geometry between the source animated character and the target character; and

wherein, when executing the transfer engine, the processor is configured to transfer a first attribute from the source animated character to the target character based on the geometric correspondence.

20. The system of 19, wherein the geometric correspondence is generated independent of a first number of geometry primitives included in the source mesh representations relative to a second number of geometry primitives included in the target mesh representation.