681 - Introduction to Computer Graphics

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Human Figure - Overview
Tasks Reaching Grasping Walking Talking Motor
Skills
Layered Construction Bone Muscle Skin
Intelligent behavior
Other Motions Facial Expression Gestures Idiosyncr
atic Secondary Motion
Reactionary Motions Clothes Hair
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Modeling the Human Form
Artistic Anatomy Anatomy related to surface
appearance versus Medical Anatomy Well-developed
literature
Forensic Science Facial Reconstruction
Plastic Surgery Surface Appearance Reconstruction
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Layered Bone-Muscle-Skin
Muscle Tendons
Fatty Tissue
Bone
Skin
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Modeling - Layered
FFD muslces
John Chadwick, ABD
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Modeling - Thalmann, EPFL
Implicit surfaces
From http//ligwww.epfl.ch/
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Modeling
Embed polyhedra in implicit surface Implicits
used for approx. collision detect
respond Polyhedra used for display
Use M.-P. Cani technique to distort implicits
based on collisions
Karan Singh, PhD
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Human Figure
Ferdi Scheepers, PhD
Use artistic anatomy to design muscles
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Human Figure
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Human Figure
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Figures - Wilhelms, UCSB
http//www.cse.ucsc.edu/wilhelms/fauna/Monkeys/5m
onk_parts.gif
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Reaching Grasping
Inverse Kinematics
What is human-like motion?
Path planning
Holding and manipulating tools
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Reaching
Arm - 7 DoF
Or 2 at elbow, 2 at wrist
Or 1 at elbow, 2 at wrist, add one at mid-forearm
Shoulder 3 DoF
Wrist 3 DoF
Elbow 1 DoF
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Reaching - heuristic
Decide on reasonable plane for arm based on task
Reduce problem to 2D arm position hand
configuration
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Reaching
Joint limits are a function of joint position
Collision avoidance with body, other limbs
Strength a function of joint position
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Whats human-like ?
Depends on orientation and task
straight-line path
Minimize total torque
Minimize maximum velocity, acceleration, jerk
Maximize comfort
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In obstacle-filled environment
Dave Miller PhD
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Grasping
Standard methods of grasping
By handle
Two finger
Wrap around
Two hand
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Walking
Gravity
Simplify dynamics Decouple reduce DoFs
Maintain balance (static)
Hip 3 DoF
Knee 1 DoF
Ankle 3 DoF
Toes 1 DoF
but usually not independent (free)
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Walking
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Walk Cycle
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Run Cycle
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Walking - Hip Angles v. Time
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Walking - Jessica Hodgins, CMU
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Facial Animation
Complex surface
Very familiar structure
Deformable surface
Very important - Principal means of communication
Facial expressions, lip-synch, prosodic facial
animation
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Facial Animation by Texture Maps
Ebert - from Getting Into Art
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Facial Animation
http//mambo.ucsc.edu/psl/sig97/siggraph97-panel.h
tml
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Facial Action Units (FACs)
From Eckman and Friesen
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Facial Animation
Fred Parke model
http//mambo.ucsc.edu/psl/sig97/siggraph97-panel.h
tml
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Digitizing Faces
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Facial Modeling - Surface Springs
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Facial Animation - Structural
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Facial Animation
Terzopolous, NYU
http//mambo.ucsc.edu/psl/sig97/siggraph97-panel.h
tml
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Facial Animation
www.cis.ohio-state.edu/research/graphics/research/
FacialAnimation/
Scott King, PhD
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Behavior
AI, Spatial reasoning, human-like reaction
Intelligent interaction with user
Engage in conversation w/gestures
Cooperation w/ other agents
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Behavior
Daniel Thalmann, LIG, EPFL
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Cloth and Clothes
Texture maps
draping
flowing
Full collision detection and response
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Simulate at what level?
Fold level - catenary curves between points of
support
Patch level - triangles or higher order patches
Weave level - warp and weft
Thread level - property and structure of thread
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Tight Fitting Clothes
Daniel Thalmann, EPFL
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Cloth
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Cloth
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Cloth
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Cloth
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Cloth
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Cloth
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Cloth
Nadia Magnenat-Thalmann, MIRALab
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Clothes
http//cs-people.bu.edu/jingbinw/Clothsim_Submit.P
DF
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Hair
Texture map
Rigid object
Model each strand
Model by clumps
Rigid underlayment w/ strands over top
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Hair
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Standards Resources
H-anim - human animation working group
http//www.h-anim.org/
MPEG-4 - Moving Pictures Expert Group
http//mpeg.telecomitalialab.com/standards/mpeg-4/
mpeg-4.htm http//ligwww.epfl.ch/mpeg4/
The Visible Human Project http//plum.ia.polsl.gli
wice.pl/DIP/visible/visible_human.html
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The Major Players
Daniel Thalmann - The Computer Graphics Lab (LIG)
at the Swiss Federal Institute of Technology
(EPFL) in Lausanne http//ligwww.epfl.ch/
Nadia Thalmann - MIRALab research group at the
University of Geneva http//www.miralab.unige.ch/
MIRAhtml/mirahome.htm
Norm Badler - Center for Human Modeling and
Simulation athe University of Pennsylvania http//
www.cis.upenn.edu/hms/
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The Major Players
Jane Wilhelms - UCSC www.cse.ucsc.edu/wilhelms/
Demitri Terzopolous - NYU mrl.nyu.edu/dt/
Michiel van de Panne - Vancouver,
B.C. www.dgp.utoronto.ca/people/van/van.html
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The Major Players
Tom Calvert - Simon Fraser www.cs.sfu.ca/people/Fa
culty/Calvert/index.html
Marie-Paule Cani - iMAGIS www-imagis.imag.fr/Membr
es/Marie-Paule.Cani/index.gb.html
Michael Cohen - MicroSoft Research www.research.m
icrosoft.com/cohen/
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The Major Players
Michael Gleicher - Wisconsin www.cs.wisc.edu/gle
icher/
Jessica Hodgins - CMU www.ri.cmu.edu/people/hodgin
s_jessica.html www.cc.gatech.edu/gvu/animation/Are
as/humanMotion/humanMotion.html