SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation
description
Transcript of SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation
![Page 1: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/1.jpg)
SIGGRAPH Asia 2011
Preview Seminar
Session 11: Animation2011/11/25
Jun SaitoMarza Animation Planet, Inc.
![Page 2: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/2.jpg)
Session 11: AnimationFacial Animation
Artist Friendly Facial Animation Retargeting
Compression and Direct Manipulation of Complex Blendshape Models
Simulated Character
Controlling Physics-Based Characters Using Soft Contacts
Modal-Space Control for Articulated Characters
Skinning Stretchable and Twistable Bones for Skeletal Shape Deformation
![Page 3: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/3.jpg)
Artist Friendly Facial Animation Retargeting
Yeongho Seol∗, Jaewoo Seo†, Paul Hyunjin Kim‡, J.P. Lewis§, Junyong Noh¶
∗†‡¶KAIST, §Weta Digital
![Page 4: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/4.jpg)
Artist Friendly Facial Animation Retargeting
MotivationRetargeting from facial motion capture does not yield enough efficiency
Method Manual Key-framing Retargeting Edits
Total time 40 min. 36 min.Time required to edit 135 frames of animation
![Page 5: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/5.jpg)
Side Note:Facial Retargeting Efficiency
Technology X used at Marza
Method Manual Key-framing Retargeting Edits
Total time 24 hrs. 5 hrs.
![Page 6: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/6.jpg)
Artist Friendly Facial Animation Retargeting
System Overview
Automatic GUI
GenerationSequential Retargeting
Graph Simplificati
on
![Page 7: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/7.jpg)
Artist Friendly Facial Animation Retargeting
Automatic GUI Generation
• Facial rig w/ arrow-like GUIo Compute dominating motion vector of each blendshape target by
WPCA• Grouping of GUI to regions and layers
o Manually paint four regions: mouth, forehead, eyes, and otherso Three layers (large, mid, small) depending on the total
displacement from neutral face
![Page 8: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/8.jpg)
Artist Friendly Facial Animation Retargeting
RetargetingCompute marker correspondence (generic face to actor’s face)by RBF warping
![Page 9: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/9.jpg)
Artist Friendly Facial Animation Retargeting
RetargetingConventional (non-sequential) retargeting
Capturedmarker positions
Marker positionsof blendshapes
![Page 10: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/10.jpg)
Artist Friendly Facial Animation Retargeting
Sequential retargeting
• Solve NNLS for blendshape target starting with largest total displacement
• Mimics animators’ workflow (coarse posing, then fine tuning)
Retargeting
![Page 11: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/11.jpg)
Artist Friendly Facial Animation Retargeting
1. Find optimal salient points using dynamic programming
2. Find piecewise optimal Bezier curve
Graph Simplification
![Page 12: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/12.jpg)
Artist Friendly Facial Animation Retargeting
Results GUI Seq. Graph Test 1 Test 2 Avg. TimeFace 1 (a) Manual key-framing 36 42 39(b) Y N N 32 36 34(c) Y N Y 30 36 33(d) Y Y N 18 20 19(e) Y Y Y 15 19 17Face 2 (a) Manual key-framing 26 23 24(b) Y N N 18 18 18(c) Y N Y 17 15 16(d) Y Y N 9 7 8(e) Y Y Y 8 5 6
Minutes required to edit 135 frames of animation
![Page 13: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/13.jpg)
Compression and Direct Manipulation of Complex
Blendshape ModelsJaewoo Seo∗, Geoffrey Irving†, J.P. Lewis‡, Junyong Noh§
∗§KAIST, †‡Weta Digital
![Page 14: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/14.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
Facial Blendshapes @ Weta:o 42,000 verticeso 730 targetso Density close to 100%o 8 fps on 8 core CPU
![Page 15: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/15.jpg)
Generic model for feature-quality, semi-realistic character• 6,821 vertices• 96 targets• Average density: 10% (max 30%)
Perhaps sparse matrix implementation is enough?
Side Note:Blendshapes @ Marza
![Page 16: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/16.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
Make humongous blendshapes more tractablewith lossy matrix compression using
hierarchical semi-separable (HSS) representation
Technique can be applied to compression and speed-up of large matrix multiplication
Contributions
![Page 17: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/17.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionPreparation: reordering
o Place high-rank blocks on “diagonal,” low-rank blocks on “off-diagonal”o Exact permutation is NP hardo Find bisection by minimizing crossing weight below, use heuristic in [Kernighan
and Lin 1970]
![Page 18: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/18.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHierarchical Semi-Separable (HSS) Representation
Tree of orthogonal matrices to compresssignificant off-diagonal structure
![Page 19: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/19.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHSS Construction [Xia et al. 2010]
![Page 20: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/20.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHSS Construction [Xia et al. 2010]
![Page 21: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/21.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHSS Construction [Xia et al. 2010]
![Page 22: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/22.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHSS Construction [Xia et al. 2010]
![Page 23: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/23.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
CompressionHSS Construction [Xia et al. 2010]
![Page 24: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/24.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
Compression• Perform SVD on matrix blocks, drop singular
values
• Optional: represent rotation using banded Householder factorization [Irving 2011]
![Page 25: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/25.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
Parallel ProcessingGPU-optimized HSS-compressed matrix multiplication
![Page 26: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/26.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
More Applications• Direct manipulation
[Lewis and Anjyo 2010] with local influence
• Cage deformation
![Page 27: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/27.jpg)
Compression and Direct Manipulation of Complex Blendshape Models
Matrix Size Dense Sparse PCA Local PCA HSS HSS+BandedCharacter # Rows # Cols MB % MB % MB % MB % MB % MB %Dumb 127173 730 354 100% 348 98.3% 138.7 39.2% 87.4 24.7% 46.8 13.2% 25.4 7.2%Dumber 155187 625 370 100% 317 85.7% 164.6 44.5% 104.7 28.3% 46 12.4% 28.1 7.6%Armadillo 106289 284 115.2 100% 173.2 150.3% 114.8 99.7% 10.4 9.0% 8.6 7.5%
τ=1e-2 for PCA, τ=1e-3 for HSS
ResultsMemory
Speed (in milliseconds) Sparse HSS HSS+BandedCharacter 8 CPUs 8 CPUs GPU 8 CPUs GPUDumb 124.21 11.22 1.47 10.73 2.18 Dumber 113.65 11.01 1.41 10.76 2.12 Armadillo 28.78 3.62 0.82 4.22 1.18
![Page 28: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/28.jpg)
Controlling Physics-Based Characters Using
Soft ContactsSumit Jain and C. Karen Liu
Georgia Institute of Technology
![Page 29: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/29.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Motivation
VIDEO
![Page 30: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/30.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Contributions• Coupling of articulated rigid body and soft
body with practical contact model
• Experiments to show soft contact model stabilizes physically simulated characters
![Page 31: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/31.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Coupled Dynamics• Articulated rigid body
Massmatrix
Coriolismatrix
Gravity Generalizedforces
Jacobianat contact
Contactforce
![Page 32: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/32.jpg)
Controlling Physics-Based Characters Using Soft Contacts
• Deformable bodyo Vertex deformation – tries to keep vertices at their rest positions
o Edge deformation – tries to keep the relative positions of the vertices
Coupled Dynamics
Stiffnessmatrix
Dampingmatrix
![Page 33: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/33.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Coupled Dynamics• Rigid + Deformable
• Adaptive deformable modelo P-ring neighborhood of contact points are
simulated, rest are treated as rigido Mass matrix is pre-computed at the rest positions
![Page 34: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/34.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Coupled Dynamics• Discretize with time step h
![Page 35: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/35.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Contact Model• Contact with friction as Linear Complementarity
Problem (LCP) [Anitescu and Potra 1997]o Advantages over penalty-based methods:
• Enforces work-less normal force, no penetration, and realistic slipping
• Explicit deformation at contact increases contact points• Low stiffness in penalty methods causes frequent penetration
![Page 36: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/36.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Locomotion Control:SIMBICON
1. Compute joint torque τs
2. Detect collisions3. Create contacts to be solved for in ODE4. Apply τs to character in ODE5. Advance one time step in ODE to get next state
![Page 37: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/37.jpg)
Controlling Physics-Based Characters Using Soft Contacts
Locomotion Control:SIMBICON + Proposed Method
1. Compute joint torque τs
2. Detect collisions3. Create contacts to be solved for in ODE
a. Convert τs to generalized torques τr
b. Convert state to generalized coordinatesc. Solve (qk+1, qk+1) and fc using LCPd. Apply fc to character in ODE
4. Apply τs to character in ODE5. Advance one time step in ODE to get next state
![Page 38: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/38.jpg)
Modal-Space Control for Articulated
CharactersSumit Jain and C. Karen Liu
Georgia Institute of Technology
![Page 39: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/39.jpg)
Modal-Space Control for Articulated Characters
MotivationArbitrary character simulation with both• long-term (anticipatory) planning• short-term (reactive) planningis prohibitively expensive to compute
?Externalforce
![Page 40: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/40.jpg)
Modal-Space Control for Articulated Characters
ContributionFormulation of modal-space character control capable of long-term planning and frequent re-planning for simulating“specific motion sequence”
Modal analysis provides:• Independent control: N-dimensional optimization to N
independent one dimensional problems• Model reduction: Allows construction of a small number of
strategies specific to certain frequencies of the dynamic system
![Page 41: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/41.jpg)
Modal-Space Control for Articulated Characters
Modal Analysis
Md and Kd are diagonal, thus
N independent 1d problems
![Page 42: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/42.jpg)
Modal-Space Control for Articulated Characters
Strategy For Modes1. Rigid modes (zero frequency)
o Corresponds to six eigenvectors in Φ with zero eigenvalueso Only affected by external forceso For long term planning
2. Low frequency modeso Corresponds to eigenvectors with
eigenvalues smaller than some thresholdo Visibly significant movements
by actuated system(see right)o For long term planning
3. High frequency modeso Less visually significanto For reactive planning
1st three principal componentsdominated by low frequency
![Page 43: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/43.jpg)
Modal-Space Control for Articulated Characters
Control Summary2. Low frequency
modes: estimate joint actuationo Solve unconstrained QP for
ideal actuation Ia* to match low frequency reference state
1. Rigid body modes: estimate contact forceso Solve QP, constrained by
Coulomb friction, for ideal contact forces f* to match rigid mode reference state
![Page 44: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/44.jpg)
Modal-Space Control for Articulated Characters
Control Summary4. Corrective forces
o Δf and ΔIa are computed to satisfy Coulomb friction
3. High frequency modes: track short-horizon plano Analytically compute high-
frequency actuation to match reference state
![Page 45: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/45.jpg)
Modal-Space Control for Articulated Characters
Results
VIDEO
![Page 46: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/46.jpg)
Stretchable and Twistable Bones for Skeletal Shape
DeformationAlec Jacobson∗ and Olga Sorkine†
∗New York University, †ETH Zurich
![Page 47: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/47.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
Motivation• Conventional bone skinning methods cause
unnatural deformation at the end of bones when scaled
![Page 48: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/48.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
Linear Blend Skinning (LBS)
• Weight for each bone
Resultingposition
Weight foreach bone
Rotation
Scale Originalposition
![Page 49: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/49.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
Stretchable, Twistable Bones Skinning
(STBS) • Weight for each bone and endpoint
o Naturally extends to use dual quaternion
Twist alongbone
Weight foreach endpoint
![Page 50: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/50.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
Results
![Page 51: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/51.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
• Manually paint• Automatic
o Bone Heat [Baran and Popovic 2007]o Bounded Biharmonic Weight [Jacobson et al. 2011]
Generating Weights
![Page 52: SIGGRAPH Asia 2011 Preview Seminar Session 11: Animation](https://reader036.fdocuments.in/reader036/viewer/2022062310/5681676e550346895ddc56b4/html5/thumbnails/52.jpg)
Stretchable and Twistable Bones for Skeletal Shape Deformation
Comparison:BH vs. BBW