Computer Animationgraphics.hallym.ac.kr/teach/2005/cga/src/09ani.pdf · 2008. 9. 10. · Computer Graphics Sun-Jeong Kim sunkim/teach/2005/cga Computer Animation December 07, 2005
Post on 02-Feb-2021
0 Views
Preview:
Transcript
Computer Graphics
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Computer Animation
December 07, 2005
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Computer Animation
“Animation”making objects change over time according to scripted actions
“Simulation”predicting how objects change over time according to physical laws
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Contents
Principles of animation
Keyframe animation
Articulated figures
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Principle of Traditional Animation – Disney –
Squash and stretchSlow in and outAnticipationExaggerationFollow through and overlapping actionTimingStagingStraight ahead action and pose-to-pose actionArcsSecondary actionAppeal
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Squash and Stretch
Squash
Stretch
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Slow In and Out
Slow
Slow
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Anticipation
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Animation Pipeline
3D modeling
Motion specification
Motion simulation
Shading, lighting, & rendering
Post-processing
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Contents
Principles of animation
Keyframe animation
Articulated figures
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Keyframe Animation (1)
Defining character poses at specific time steps called “keyframes”
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Keyframe Animation (2)
Interpolating variables describing keyframes to determine poses for character “in-between”
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Inbetweening (1)
Linear interpolationusually not enough continuity
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Inbetweening (2)
Spline interpolationmaybe good enough
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Inbetweening (3)
Spline interpolationmaybe good enoughmay not follow physical laws
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Inbetweening (3)
Spline interpolationmaybe good enoughmay not follow physical laws
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Inbetweening (4)
Inverse kinematics or dynamics physical laws
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Contents
Principles of animation
Keyframe animation
Articulated figures
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Articulated Figures (1)
Character poses described by the set of rigid bodies connected by “joints”
Base
Arm
Hand
Scene Graph
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Articulated Figures (2)
Well-suited for humanoid characters
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Articulated Figures (3)
Inbetweeningcomputing joint angles between keyframesconsidering the length constancy
Right Wrong
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Example: Walk Cycle (1)
Articulated figure:
Hip
Knee
Foot
Upper Leg
Ankle
Lower Leg
Hip Rotate
Hip Rotate + Knee Rotate
Upper Leg (Hip Rotate)
Foot (Ankle Rotate)
Lower Leg (Knee Rotate)
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Example: Walk Cycle (2)
Hip joint orientation:
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Example: Walk Cycle (3)
Knee joint orientation:
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Example: Walk Cycle (4)
Ankle joint orientation:
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Challenge of Animation
Temporal aliasingmotion blur
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Temporal Ailasing
Artifacts due to limited temporal resolutionstrobingflickering
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Temporal Ailasing
Artifacts due to limited temporal resolutionstrobingflickering
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Temporal Ailasing
Artifacts due to limited temporal resolutionstrobingflickering
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Temporal Ailasing
Artifacts due to limited temporal resolutionstrobingflickering
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Motion Blur
Compositing weighted images of adjacent frames
removing parts of signal under-sampled in time
Sun-Jeong Kim http://www.hallym.ac.kr/~sunkim/teach/2005/cga
Summary
Animation requires ...modelingscriptinginbetweeninglighting and shadingrenderingimage processing
top related