1.The Challenge of Interactivity 2.Parametric Blending -Building Blend-Spaces -Using Virtual Example Grids for Param

2. 1.The Challenge of Interactivity 2.Parametric Blending -Building Blend-Spaces -Using Virtual Example Grids for Parameterization -Combined and Layered Blend-Spaces 3.Comparison with Academic Research 4.Procedural Animations Talk Overview

5. Issues with Animation Blending • 1 – Blend-Weights can be complex to calculate • 2 – Blend-Weights are not intuitive • 3 – Blend-Weights can give unpredictable results • Is this always a problem? • When is it a problem?

6. Part 2 • Parametric Blending

7. 1. What is it? An extension of animation blending A method to create predictable blending-results 2. How does it work? It uses the captured properties of a motion-clip directly It generates the blend-weights in relation to these properties 3. What can we use it for? Parametric Blending

12. Animation vsParametric Blending The hard part is to generate Correct Blend-Weights and Natural Results! Getting both at the same time can be an extremely difficult process

13. 1.Accurate Parameter Mapping 2.Artist-Directed Blending 3.Continuous-Control 4.Runtime Efficient 5.Memory Efficient Conclusion:if only one of these features is missing, then it’s very hard to use it in game-productions. The 5 Features a Parameterizer must have!

14. Building-Blocks for a Parameterizer

15. Virtual Example Grids • The Offline Process • The step-by-step process how to setup a • parametric group for locomotion.

16. Virtual Example Grids • The Offline Process • Step 1: • Asset Selection

17. Virtual Example Grids • The Offline Process • Step 2: • Parameter Extraction

18. Virtual Example Grids • The Offline Process • Step 3: • Setup of the Blend-Space

19. Virtual Example Grids • The Offline Process • Step 4: • Blending Annotations • Weird Issue: • Different combinations of Blend-Weights, • can give you a blended motion with Identical Parameter, • but totally different Visual Poses

20. Virtual Example Grids • The Offline Process • Advantages of Annotations • 1.Artist Directed Blending • 2.No “Scattered Data Interpolation” Problem • 3.Continuous Control • 4.Control over Performance • 5.Simple, Precise and Easy to Debug

21. Virtual Example Grids • The Offline Process • Step 5: • Extrapolated Pseudo Examples

22. Virtual Example Grids • The Offline Process • Step 6: • Virtual Example Grids

23. Virtual Example Grids • The Runtime Process

24. Virtual Example Grids • The Runtime Process • Step 1: • Parameterization:

25. Virtual Example Grids • The Runtime Process • Step 2: • Time-Warping

26. Virtual Example Grids • The Runtime Process • Step 3: • Pose-Blending

27. Exponential Asset Explosion 1D - 3 assets for move-speed 2D - 9 assets for move-speed / turn left-right 3D - 27 assets for speed / turn left-right / uphill-downhill 4D – 27*8 assets for speed / turn left-right / uphill-downhill multiply by 8 move-directions ---------------------------------------------------------- =216 (for 1 parametric group) -This is the raw bare minimum for a full featured character, regardless of the blending method. -Our practical maximum was 34 assets per group Debugging Nightmare -More then 3 dimensions are hard to visualize & debug -Dimensionality-Problem is the Dead End for Parametric Blending Curse of Dimensionality

28. But 3D is not enough! -with 3D you have only 3 Parameters to control -in a game you will need much more What’s the Solutions? -build small Blend-Spaces and combine them -or we can layer Blend-Spaces Curse of Dimensionality

29. Combined Blend-Spaces • Our Blend-Spaces are limited to 3 dimensions • But it is possible to combine small blend-spaces

30. The Layer Model Types of Layered Animations - Overwrite Animations - Additive Animations - Combination of both Methods in one Asset Layered Blending

31. Parametric Weapon Aiming Parametric Blending used in Layers

32. Parametric Gaze-control (including eye-lids) Parametric Blending used in Layers

33. We used only small Blend-Spaces (max 3D) With combinations it was possible to control 4D With layering it was possible to control up to 8D Virtual Example Grids Summary

34. Part 3 • Comparison with Academic Research

35. Techniques for a Parameterizer

36. Virtual Example Grids vs Radial Basis Functions “Verbs and Adverbs: Multidimensional motion interpolation.” by Charles Rose, Bobby Bodenheimer and Michael Cohen (1998) “Artist directed IK using RBF interpolation.” by Charles Rose, Peter-Pike Sloan and Michael Cohen (2001)

37. Virtual Example Grids vs K-Nearest Neighbors “Automated extraction and parameterization of motions” by Lucas Kovarand Michael Gleicher (2004)

38. Combination of IK-solvers IK-Solvers (2B, 3B & CCD-IK) generate new poses Procedural Motion Warping Typical Applications Fix of Blending-Artifacts Ground Alignment Recoil Kinematic Methods

39. From RBF to VEG 1.We started with an RBF implementation -was slow, no control over blending 2.We combined RBF with KNN -faster, but now we had snaps in the motions 3.Smoothing of Blend-Weights to avoid snaps • -worked, but smoothing messed up the parameterization • 4.Manual Annotation • -this fixed all issues and made SDI redundant • 5.We used VEGs to maximize performance

40. Part 4 • Procedural Animations

42. Physically Based Animations • Just Ragdolls • Ragdolls & Animation Blending • Procedural Hit-Reactions • Animated Hit-Reactions • Inverse Dynamics

43. Summary • 1.Animation-Data is the foundation • 2.Blend-Spaces and Parametric Animations • 3.Annotations • -Annotations to improve the motion-quality • -Annotations to eliminate the SDI problem • -Annotations to accelerate the pose-blender • -Annotations with Pseudo-Examples to save memory • 4.Virtual Example Grids • 5.Combined and Layered Blend-Spaces • 6.Procedural Techniques

44. Special thanks for the Help with this Presentation: • Benjamin Block, Chris Butcher, Daniele Duri, Frieder Erdman, • IvoZoltan Frey, Mathias Lindner, Michelle Martin • Peter North, David Ramos, Sven van Soom, • Peter Söderbaum, Alex Taube, • KarlheinzWatemeier, • The Best is Yet to Come • You can find a more detailed comparison between different • Parametric Methods after the Q&A Slide

46. The Best is Yet to Come • You can find a more detailed comparison between different • Parametric Methods

47. Reference & Comparison

48. Accurate Parameter Mapping Artist-Directed Blending Continuous-Control Runtime Efficient Memory Efficient Requirements for a Parameterizer

49. Regular Grid Interpolation Synthesis “Interpolation synthesis for articulated figure motion” by Douglas Wiley and James Hahn (1997) 1.Accurate Parameter Mapping: YES(but depends mainly on the density of the grid) 2.Artist-Directed Blending: YES(but artist are forced to fill a grid with motions) 3.Continuous-Control: YES 4.Run-time Efficient: YES 5.Memory Efficient: NO(memory requirements and the amount of assets were insane)

50. Scattered Data Interpolation (1/5) Radial Basis Functions “Verbs and adverbs: Multidimensional motion interpolation.” by Charles Rose, Bobby Bodenheimer and Michael Cohen (1998) 1.Accurate Parameter Mapping: ???(For IK-tasks very inaccurate) 2.Artist-Directed Blending: NO (In many cases blend-poses were more or less random) 3.Continuous-Control: YES (RBFs are smooth) 4.Run-time Efficient: NO (The parameterizer was using interpolation per DOF) 5.Memory Efficient: YES (Only key-examples are needed)