foundations of computer graphics (spring 2010) cs 184, lecture 24: animation cs184 many slides...
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![Page 1: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/1.jpg)
Foundations of Computer Graphics Foundations of Computer Graphics (Spring 2010)(Spring 2010)
CS 184, Lecture 24: Animation
http://inst.eecs.berkeley.edu/~cs184
Many slides courtesy Adam Finkelstein, James O’Brien, others
![Page 2: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/2.jpg)
To DoTo Do
Submit HW 4 (today)
Start working on HW 5 (can be simple add-on)
![Page 3: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/3.jpg)
These LecturesThese Lectures
3 classical prongs in graphics pipeline: Modeling, Rendering, Animation
We talk a little about animation or motion
Limited time, hence fun lectures, not covered in detail on final
Possibility for HW 5, but only if very motivated
Will also show historical videos
![Page 4: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/4.jpg)
History of Computer AnimationHistory of Computer Animation
Video (also shown first class)
![Page 5: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/5.jpg)
Computer AnimationComputer Animation
What is animation? Motion of objects (change
behavior with time) Often scripted with spline curve Trivial example animations for HW 3
What is simulation? Predict how objects move according to laws of physics Graphics animation often involves “directable” simulation Fracture video (O’Brien)
Geri’s game: Pixar
![Page 6: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/6.jpg)
2D and 3D Animation2D and 3D Animation
Homer 3DHomer 2D
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Principles of Traditional AnimationPrinciples of Traditional Animation
![Page 8: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/8.jpg)
Squash and StretchSquash and Stretch
![Page 9: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/9.jpg)
AnticipationAnticipation
![Page 10: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/10.jpg)
OutlineOutline
Keyframes
Articulated Figures
Kinematics
Dynamics
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Computer AnimationComputer Animation
Simplest idea: Keyframing or in-betweening
Character poses at specific keyframes Computer interpolates in-between frames
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How to Interpolate?How to Interpolate?
Linear interpolation not usually good enough
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Keyframe InterpolationKeyframe Interpolation
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KeyframingKeyframing
![Page 15: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/15.jpg)
Motion Capture (recorded)Motion Capture (recorded)
![Page 16: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/16.jpg)
Inverse KinematicsInverse Kinematics
Consider structure of articulated object
![Page 17: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/17.jpg)
OutlineOutline
Keyframes
Articulated Figures
Kinematics
Dynamics
![Page 18: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/18.jpg)
Articulated FiguresArticulated Figures
Rigid objects connected by joints
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Humanoid CharactersHumanoid Characters
![Page 20: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/20.jpg)
OutlineOutline
Keyframes
Articulated Figures
Kinematics
Dynamics
![Page 21: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/21.jpg)
Kinematics and DynamicsKinematics and Dynamics
Kinematics Consider only motion. Positions, velocity, acceleration
Dynamics Considers underlying forces. Initial conditions+physics
Articulated objects Forward and inverse kinematics Possibly forward and inverse dynamics Many links to robotics, mechanics and other fields
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Simple 2 link armSimple 2 link arm
2 links connected by rotational joints
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Forward KinematicsForward Kinematics
Specify joint angles, computer finds end-effector
![Page 24: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/24.jpg)
Forward KinematicsForward Kinematics
Then specify joint motions with spline curves
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Inverse KinematicsInverse Kinematics
Animator knows/specifies end-effector System must compute joint angles Harder, topic of next lecture, possible HW 5
![Page 26: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/26.jpg)
Summary of KinematicsSummary of Kinematics
Forward kinematics Specify joint angles, system computes end-effector
Inverse kinematics Easier to specify for most animations Animator specifies end-effector System computes joint angles (harder) “Goal-Directed” motion (animator specifies end-goals)
![Page 27: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/27.jpg)
OutlineOutline
Keyframes
Articulated Figures
Kinematics
Dynamics
![Page 28: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/28.jpg)
DynamicsDynamics
Consider underlying forces
Motion from initial conditions, forces
In graphics, include goals Optimization to satisfy goals and physics
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DynamicsDynamics
Simulation to ensure physical realism
Spacetime Constraints [Witkin and Kass 88] Goals (e.g. jump from here to there) Optimized motion (e.g. minimize energy or torque) Character’s physical structure (articulation) Other constraints (foot contact, floor etc.) Iterative optimization given constraint, objective
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Spacetime ConstraintsSpacetime Constraints
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Spacetime ConstraintsSpacetime Constraints
![Page 32: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/32.jpg)
Spacetime ConstraintsSpacetime Constraints
Advantages Directly specify goals, not low-level joint angles etc. Can easily edit and vary motions
Disadvantages Specifying constraints, objective functions Optimization, and avoiding local minima
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VideoVideo
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Dynamics: Physical SimulationDynamics: Physical Simulation
Rigid Bodies
Soft deformable objects
Cloth
Liquids (water)
Gases (smoke, fluids)
Wrinkle Synthesis Video
![Page 35: Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 24: Animation cs184 Many slides courtesy Adam Finkelstein,](https://reader033.vdocuments.us/reader033/viewer/2022051618/56649d385503460f94a118c0/html5/thumbnails/35.jpg)
History of Computer Animation 2History of Computer Animation 2
Part 2 of video