1. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE Motion Pattern Preserving IK Operating in the Motion Principal Coefficients Space Schubert R. Carvalho, Ronan Boulic and Daniel Thalmann Presented by Schubert R. Carvalho

2. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Overview Introduction Related Work A Model for Editing Experiments Conclusions and Future Work

3. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Introduction Challenges of Motion Editing Techniques –Preserve the characteristics of the original animation –Impose continuity between frames Motivation –How to edit a motion by constraining just one pose without adding discontinuities? 1 2

4. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Related work Traditional Motion Editing [Lee et. al. 1999] [Gleicher 2001] [Kulpa 2005] [Le Callennec and Boulic 2006] [Liu et. al. 2006] Principal Component Analysis in Computer Animation [Alexa and Müller 2000] [Safanova et. al. 2004] [Glardon et. al. 2004] [Urtasun and Fua 2004]

5. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 A Model for Editing Three basic issues –Motion Parameterization –Constraining a Single Posture in the Motion PC Space –Impose Continuity

6. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Motion Parameterization Principal Components Analysis (PCA) Motion Database Ψ M = [ Θ t 0,..., Θ t k,..., Θ t 1 ] Θ t k = [ Φ 1, P 1, Φ j,..., Φ n ] root Joints angles 0≤ k ≤ 1 Ψ 1, Ψ 2,..., Ψ M Pose PCA PCPCs m ≤ M Ψ D ≈ Ψ o + ∑α D i E i m I=1

7. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Constraining Formulation Constraining a Single Pose in the Motion PC Space Δα = J ( α ) t ε Δ x p=3; m=8; n=93; D=12276

8. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Imposing Continuity Continuity is enforced through the PCA parameters. While not converged do 1: Δα J(α) t ε Δ x 2: α D α D + Δ α D 3: Θ D Ψ o t k + α D E t k end while 4: Ψ D Ψ o + ∑ α D i E i m I=1 PC (E t k )Time (s)Nb. Of Iterations 24000019196 311000050214 44200019929 590004194 61625757 70.500235 80.484221 90.531247 Algorithm’s Convergence

9. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Experiments: Editing and Style (1) -5 0 5 10 15 20 25 30 35 40 -5 -4 -3 -2 -1 0 1 2 3 4 5 1st Component 2nd Component 1 2 3 4 5 Input Motion Golf Swing Database

10. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Experiments: Editing and Style (2) damping = 10; num. of iterations = 1500; tracked error = 0.01m.

11. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Experiments: Visual Comparison (1) f = 93f = 94

12. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Experiments: Visual Comparison (2) PIKOur Approach N. of Constraints51 Fr. Constrained111 Presented Artifacts Feet Sliding, Balance and Arms’ Inter Penetration Nothing Detected Computation Time1 sec.100 sec.

13. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Conclusions If the motion needs just an adjustment of one key event, our approach can provide faster and more realistic results than current approaches. Our approach provided quality results with less tuning from the user side. Future work Extend the current method to treat multiple constraints. Extend the current method to constrain multiple frames (if necessary).

14. MOTION PATTERN PRESERVING IK OPERATING IN THE MOTION PRINCIPAL COEFFICIENTS SPACE WSCG 2007 Thanks four your attention!