1 CNM 190 CNM 190 Advanced Digital Animation Advanced Digital Animation Lec Lec 12 : Walk Cycles & Autonomous Motion 12 : Walk Cycles & Autonomous Motion Dan Garcia Dan Garcia, EECS (co-instructor) , EECS (co-instructor) Greg Niemeyer, Art (co-instructor) Greg Niemeyer, Art (co-instructor) Jeremy Huddleston Jeremy Huddleston, EECS (TA) EECS (TA) John John Cleese Cleese “Silly Walk Silly Walk” animated using SPAM software animated using SPAM software 2/24 Walk Cycles & Autonomous Motion http://inst.eecs.berkeley.edu/~selfpace/ CNM190 Overview Overview Walk Cycles Walk Cycles Definition, History Definition, History References References What makes a What makes a great walk cycle? great walk cycle? Examples Examples SPAM demo SPAM demo UCB Research UCB Research Autonomous Motion Autonomous Motion Definition Definition Flow Chart Flow Chart Finite State Machines Finite State Machines Brian Brian Mirtich Mirtich Demo Demo 3/24 Walk Cycles & Autonomous Motion http://inst.eecs.berkeley.edu/~selfpace/ CNM190 Walk Cycles : Definition & History Walk Cycles : Definition & History Definition Definition A sequence of frames capturing a walk movement A sequence of frames capturing a walk movement History History Since the early days of hand-drawn animation, Since the early days of hand-drawn animation, these have been used to get characters from A to B these have been used to get characters from A to B and, most importantly, to and, most importantly, to capture & convey emotion capture & convey emotion www.idleworm.com/how/anm/02w/walk1.shtml 4/24 Walk Cycles & Autonomous Motion http://inst.eecs.berkeley.edu/~selfpace/ CNM190 References (1) References (1) The Illusion of Life The Illusion of Life : : Disney Animation Disney Animation by Frank by Frank Thomas & Ollie Thomas & Ollie Johnston Johnston Two of Disney Two of Disney’s “Nine Old Men Nine Old Men” “… “… gives many glimpses gives many glimpses into the workings of the into the workings of the animation masters at animation masters at Disney's during the Disney's during the Golden Age of animation Golden Age of animation” On every professional On every professional animator animator’ s bookshelf s bookshelf 576 Pages 576 Pages Disney Editions, 1995 Disney Editions, 1995 Out-of-print! ~$40 Out-of-print! ~$40 en.wikipedia.org/wiki/The_Illusion_Of_Life 5/24 Walk Cycles & Autonomous Motion http://inst.eecs.berkeley.edu/~selfpace/ CNM190 References (2) References (2) The Animator The Animator ’ ’ s Survival Kit s Survival Kit by Richard Williams by Richard Williams 352 pages 352 pages Faber & Faber, 2002 Faber & Faber, 2002 ~$20 new, ~$15 used ~$20 new, ~$15 used Cartoon Animation Cartoon Animation by Preston Blair by Preston Blair 144 pages 144 pages Walter Foster, 1994 Walter Foster, 1994 ~$15 new, ~$10 used ~$15 new, ~$10 used www.amazon.com 6/24 Walk Cycles & Autonomous Motion http://inst.eecs.berkeley.edu/~selfpace/ CNM190 References (3) References (3) Principles of Traditional Principles of Traditional Animation Applied to Animation Applied to 3D Computer 3D Computer Animation Animation , Computer , Computer Graphics, pp. 35-44, Graphics, pp. 35-44, 21:4, July 1987 21:4, July 1987 (SIGGRAPH 87). (SIGGRAPH 87). by John by John Lasseter Lasseter He shared the secrets of the He shared the secrets of the kingdom with 3D animators kingdom with 3D animators There There’ s an abridged version s an abridged version online (URL above) online (URL above) www.siggraph.org/education/materials/HyperGraph/animation/character_animation/principles/prin_trad_anim.htm
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CNM 190CNM 190Advanced Digital AnimationAdvanced Digital Animation
Walk CyclesWalk Cycles Definition, HistoryDefinition, History ReferencesReferences What makes aWhat makes a
great walk cycle?great walk cycle? ExamplesExamples SPAM demoSPAM demo UCB ResearchUCB Research
Autonomous MotionAutonomous Motion DefinitionDefinition Flow ChartFlow Chart Finite State MachinesFinite State Machines Brian Brian Mirtich Mirtich DemoDemo
Walk Cycles : Definition & HistoryWalk Cycles : Definition & History
DefinitionDefinition A sequence of frames capturing a walk movementA sequence of frames capturing a walk movement
HistoryHistory Since the early days of hand-drawn animation,Since the early days of hand-drawn animation,
these have been used to get characters from A to Bthese have been used to get characters from A to Band, most importantly, to and, most importantly, to capture & convey emotioncapture & convey emotion
The Illusion of LifeThe Illusion of Life : :Disney AnimationDisney Animation by Frankby Frank Thomas & OllieThomas & Ollie
JohnstonJohnston Two of DisneyTwo of Disney’’ss
““Nine Old MenNine Old Men”” “…“… gives many glimpses gives many glimpses
into the workings of theinto the workings of theanimation masters atanimation masters atDisney's during theDisney's during theGolden Age of animationGolden Age of animation””
On every professionalOn every professionalanimatoranimator’’s bookshelfs bookshelf
Principles of TraditionalPrinciples of TraditionalAnimation Applied toAnimation Applied to3D Computer3D ComputerAnimationAnimation, Computer, ComputerGraphics, pp. 35-44,Graphics, pp. 35-44,21:4, July 198721:4, July 1987(SIGGRAPH 87).(SIGGRAPH 87). by John by John LasseterLasseter He shared the secrets of theHe shared the secrets of the
kingdom with 3D animatorskingdom with 3D animators ThereThere’’s an abridged versions an abridged version
What makes a great walk cycle? (1)What makes a great walk cycle? (1)
Four distinct posesFour distinct poses Contact Contact –– feet at furthest extension of walk (start here) feet at furthest extension of walk (start here) Recoil Recoil –– where the character impacts the ground where the character impacts the ground Passing Passing –– an an ‘‘in-betweenin-between’’ of of Recoil and High PointRecoil and High Point High PointHigh Point –– character character’’s body stretched to maxs body stretched to max
What makes a great walk cycle? (2)What makes a great walk cycle? (2)
Depending on theDepending on theemotion to convey,emotion to convey,these four basicthese four basicposesposes may changemay change No 2-pt contact poseNo 2-pt contact pose
for run cyclesfor run cycles E.g., skipping requiresE.g., skipping requires
more thanmore than 4 poses4 poses
Note several thingsNote several things Path of headPath of head Lean ofLean of body, headbody, head ArmsArms & hands matter!& hands matter!
What makes a great walk cycle? (3)What makes a great walk cycle? (3)
Four-legged figuresFour-legged figuresare similar, but moreare similar, but morecomplicatedcomplicated Are legs in phase?Are legs in phase? Horses have vastlyHorses have vastly
different cyclesdifferent cyclesdepending on speeddepending on speed
This is relevant forThis is relevant forboth teamsboth teams Elephants, GiraffesElephants, Giraffes Robot DogRobot Dog
What makes a great walk cycle? (5)What makes a great walk cycle? (5)
The walk cycleThe walk cycleshould have good,should have good,consistent transverseconsistent transversemotions (L-R)motions (L-R) E.g., Note arms; theyE.g., Note arms; they
dondon’’t just rotate int just rotate indirection of walkdirection of walk
Walk Generation Walk Generation –– Use Use MoCapMoCap!!
We sawWe saw a a MoCapMoCapdemo last weekdemo last week
With a talented actor,With a talented actor,you can create anyyou can create anyhuman motionhuman motion E.g., E.g., LoTR LoTR ““GollumGollum”” You can also use theYou can also use the
data as a startingdata as a startingpoint for editingpoint for editing
Might be lots of rawMight be lots of rawdata cleaning updata cleaning up
Walk Cycle SummaryWalk Cycle Summary……PersonalityPersonality
““The objective of the [Animation]The objective of the [Animation]principles previously discussed [inprinciples previously discussed [inhis SIGGRAPH paper] are to givehis SIGGRAPH paper] are to givethe characters in an animation the characters in an animation aapersonality that appeals to thepersonality that appeals to theviewersviewers..””
““The different principles should beThe different principles should beapplied in a fashion to produce aapplied in a fashion to produce aconsistent personality.consistent personality.””
““This means that This means that the animatorthe animatormust have a good idea of themust have a good idea of thedesired personality desired personality beforebeforebeginning the animationbeginning the animation..””
UCB Walk-Related ResearchUCB Walk-Related Research
There has been a lot ofThere has been a lot ofresearch done hereresearch done hererelating to walk cycles &relating to walk cycles &MoCap MoCap databasesdatabases Electronic Arts gave usElectronic Arts gave us
some of their some of their MoCap MoCap datadata Okan Arikan Okan Arikan (now a Prof(now a Prof
at U Texas) led charge,at U Texas) led charge,with Profs Owith Profs O’’Brien, ForsythBrien, Forsyth
Knowing When to PutKnowing When to PutYour Food DownYour Food Down
Pushing people aroundPushing people around Motion Synthesis fromMotion Synthesis from
More than simplyMore than simplyspacetime spacetime constraintsconstraints
This fieldThis field is VAST, foris VAST, forsome the Holy Grail!some the Holy Grail! Artificial intelligenceArtificial intelligence Artificial lifeArtificial life RoboticsRobotics Video gamesVideo games Crowd, herd & flockingCrowd, herd & flocking
simulationssimulations
Real-time >> BatchReal-time >> Batch In terms of $, interestIn terms of $, interest
Lots of questions ; this is hard!Lots of questions ; this is hard!
Why / Where,Why / Where,often in real timeoften in real time…… What behavior isWhat behavior is
generated /generated / issued?issued? Where do we go?Where do we go? What is the emotion?What is the emotion? WhatWhat’’s our motivation?s our motivation? What is our mood asWhat is our mood as
the result of the newthe result of the newmotion / location?motion / location?
When do we haveWhen do we havebirths / deaths?births / deaths?
How do we,How do we,often in real timeoften in real time…… select the animationsselect the animations
from DB? Orfrom DB? Or…… auto-generate theauto-generate the
animation?animation? blend the animationsblend the animations
we have with what iswe have with what isrequested?requested?
Brian Brian MirtichMirtich, 1996 UCB Ph.D., 1996 UCB Ph.D.
Thesis: Thesis: ““ImpulseImpulse - -based Dynamicbased DynamicSimulation of RigidSimulation of RigidBody SystemsBody Systems”” He focused onHe focused on
dynamic constraintsdynamic constraints Very cool work!Very cool work!
““Creature WarCreature War”” demo demo His purpose: show offHis purpose: show off
his simulatorhis simulator Great exampleGreat example ofof
Big idea : Give manyBig idea : Give manycharacters their own FSMcharacters their own FSM
Craig ReynoldsCraig Reynolds ““foundedfounded””first first Boids Boids in 1986; A-Lifein 1986; A-Life SeparationSeparation –– steer to avoid steer to avoid
crowding local crowding local flockmatesflockmates AlignmentAlignment –– steer towards steer towards
the average heading ofthe average heading oflocal local flockmatesflockmates
CohesionCohesion –– steer to move steer to movetoward the averagetoward the averageposition of local position of local flockmatesflockmates
Emergent Emergent behavoirbehavoir!! CrowdsCrowds just another just another