Method for motion simulation of an articulated figure using animation input

• US 20040169656A1
• Filed: 11/17/2003
• Published: 09/02/2004
• Est. Priority Date: 11/15/2002
• Status: Abandoned Application

• Current Assignee: Warner Bros Entertainment Incorporated (Warner Bros. Discovery, Inc.)
• Original Assignee: Warner Bros Entertainment Incorporated (Warner Bros. Discovery, Inc.)
• Inventors: James, Oliver, David Piponi, Daniele Paolo
• Application Number:
  US10/715,778
• Publication Number:
  US 20040169656A1
• Time in Patent Office: Days
• US Class Current: 345/473
• CPC Class Codes: G06T 13/80 2D [Two Dimensional] animation, e.g. using sprites
• CPC Class Codes: G06T 15/20 Perspective computation
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 2200/08 involving all processing steps from image acquisition to 3D model generation
• CPC Class Codes: G06T 2210/61 Scene description
• CPC Class Codes: G06T 7/55 from multiple images
• CPC Class Codes: H04N 5/262 Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects

Abstract

Motion of an articulated figure in response to an external force function and to a co-acting internal force function is simulated, for use in computer animation. The internal force function is defined by applying an inverse-dynamic method to solve for internal forces driving the articulated figure to conform to a predefined animation curve. The internal force function may be scaled in any desired way, an combined with the external force function as input for a forward-dynamics motion simulation. The resulting motion simulation models a combined effect of the external force function and the predefined animation curve on motion of the articulated figure.

Claims

1. A method for determining movements of an articulated figure for use in computer-generated animation, the method comprising:

accessing a pose sequence Q(t), wherein Q(t) comprises position values associated with segments of an articulated figure at sequential times of the pose sequence;

calculating an inverse-dynamics solution F(t), wherein F(t) comprises calculated torque values for the segments during sequential forward-looking intervals Δ

t, such as would result in movements of the articulated figure corresponding to Q(t);

accessing force data G(t), wherein G(t) comprises external force values for simulating a response of the articulated figure; and

simulating a dynamic response of the articulated figure in reaction to a sum of F(t) and G(t), thereby defining a simulated pose sequence P(t).

2. The method of claim 1, further comprising setting Δ

t equal to a user-determinable value, prior to the calculating step.

3. The method of claim 1, further comprising scaling F(t) by a scale factor s, whereby the simulating step defines P(t) by a simulated dynamic response of the articulated figure in reaction to a sum of F(t) scaled by s and G(t).

4. The method of claim 3, further comprising receiving user input defining a value of s, prior to the scaling step.

5. The method of claim 3, wherein the scaling step further comprises scaling F(t) by s, wherein s is less than one.

6. The method of claim 3, wherein the scaling step further comprises scaling F(t) by s, wherein s is greater than one.

7. The method of claim 3, wherein the scaling step further comprises scaling F(t) by s, wherein s comprises a time-dependent function.

8. The method of claim 1, further comprising calculating G(t) using P(t) as input to determine collision events between the articulated figure and other simulated objects, whereby impulse values for G(t) are determined.

9. The method of claim 1, wherein the calculating step and the simulating step are performed concurrently.

10. The method of claim 1, wherein the simulating step is performed after the calculating step has completed by defining F(t) over an animation sequence.

12. The computer-readable media of claim 1, wherein the instructions further comprise setting Δ

t equal to a user-determinable value, prior to the calculating step.

13. The computer-readable media of claim 1, wherein the instructions further comprise scaling F(t) by a scale factor s, whereby the providing step provides a sum of F(t) scaled by s and G(t).

14. The computer-readable media of claim 13, wherein the instructions further comprise receiving user input defining a value of s, prior to the scaling step.

15. The computer-readable media of claim 13, wherein the instructions further comprise scaling F(t) by s, wherein s is less than one.

16. The computer-readable media of claim 13, wherein the instructions further comprise scaling F(t) by s, wherein s is greater than one.

17. The computer-readable media of claim 13, wherein the instructions further comprise scaling F(t) by s, wherein s comprises a time-dependent function.

11. A computer-readable media encoded with instructions for determining movements of an articulated figure for use in computer-generated animation, the instructions comprising:

accessing a pose sequence Q(t), wherein Q(t) comprises position values associated with segments of an articulated figure at sequential times of the pose sequence;

calculating an inverse-dynamics solution F(t), wherein F(t) comprises calculated torque values for the segments during sequential forward-looking intervals Δ

t, such as would result in movements of the articulated figure corresponding to Q(t);

accessing force data G(t), wherein G(t) comprises external force values for simulating a response of the articulated figure; and

providing a sum of F(t) and G(t) suitable for input in simulating a dynamic response of the articulated figure using a forward-dynamics motion simulation to determine a simulated pose sequence P(t).

18. The computer-readable media of claim 11, wherein the instructions further comprise calculating G(t) using P(t) as input to determine collision events between the articulated figure and other simulated objects, whereby impulse values for G(t) are determined. The computer-readable media of claim 11, wherein the instructions further comprise performing the calculating step and the simulating step concurrently.

19. The computer-readable media of claim 11, wherein the instructions further comprise performing the simulating step after the calculating step has completed by defining F(t) over an animation sequence.