Computer Animation: Outline It’s Past, It’s Present And its Future at UW A brief history of computer animation (animation appreciation) – Video! Michael Gleicher Overview of the Production Process Graphics Group Where motion comes from – Video! Department of Computer Sciences Animation at UW CS University of Wisconsin, Madison (what we do) – Video! www.cs.wisc.edu/graphics Graphics and Animation Classes (what you can do) – Video! Goals Caveats Give you some idea of what This talk is skewed toward 3D Computer Animation is about Animation for film and video Give you some idea of where (some That ignores lots of interesting stuff of) the hard problems are 2D and image effects Games, Visualization, Simulation, ... Give you an idea of we do Focus on character animation Try to get you excited about doing it Over-emphasize my heroes Show some fun video This is a rehash of some old stuff Little (or no) technical content Timeline Pioneer Days (pre-1980s) What was happening: ComingComing EarlyEarly ModernModern Early pioneers (in research labs) PioneersPioneers OfOf DaysDays EraEra started making movies with computers AgeAge General Story: 1982 1987 1995 It was hard to make pictures with Phases of the history of animation computers, but people did it anyway Why it ended: Computer Animation becomes feasible 1 Early Days (early to mid- Early Days (early to mid- 1980s) 1980s) What was happening: Notable examples: Computer animation in film and video TRON (‘82), The Last Starfighter (’84) What it looked like: Many TV spots and commercials Computer graphics What it looks like today: Things computers could draw well Quaint Chrome! Flying Logos! Why it ended AUDIENCES grew more savvy Works Ant Last Starfighter Sexy Robot Flying Logos 2 Early Days (early to mid- 1980s) Luxo Jr Notable examples: TRON (‘82), The Last Starfighter (’84) Many TV spots and commercials What it looks like today: Quaint Why it ended AUDIENCES grew more savvy A critical moment in Computer Animation Comes of Age history… (late 80s – mid 90s) Computer Animation not just for Luxo Jr. computer animation’s sake Pixar, 1986 J. Lasseter (dir) First computer animation nominated for an Academy Award Notable character animation It’s the motion! (well, it looks good too) Beauty and the Beast, 1991 Jurassic Park, 1993 Glory Days of Computer Animation Another important film… What will they do next? Toy Story Notable examples Pixar, 1995 Tin Toy ’88 (and other Pixar Shorts) J. Lasseter (dir) Terminator 2 ’91 Beauty and the Beast ’91 Feature length, 3D animated film Jurrassic Park ’93 Financially and artistically successful … more and more and more … Everybody wants to copy 3 Why is Toy Story Different? End of the Glory Days? Tin Toy Toy Story No more firsts? 1988 1995 Glory is for good films, not cool effects Not just animation for animation’s sake Same basic technology as shorts Hackers are not the heroes anymore Different magnitude of problems Technology is generally available. How to deal with all the bits! (Kindof) Must hold attention for 90 minutes Artistic factors drive Toy Story++ Shrek More and more animated films Greater levels of complexity Antz, Bugs Life, Toy Story 2, … New artistic styles and possibilities Tarzan, Prince of Egypt Final Fantasy,… Current state of the art Final Fantasy The Modern Era (’95 - …) No more firsts? Don’t believe your eyes! Anything is possible! Seamless integration of CG and real Some landmarks Titanic ’97 What Dreams May Come ‘98 The Mummy, Episode 1, The Matrix ’99 Hollowman, Perfect Storm ’00 Pearl Harbor ’01 4 Hollowman The Modern Era (’95 - …) No more firsts? Don’t believe your eyes! Anything is possible! Seamless integration of CG and real Some landmarks Titanic ’97 What Dreams May Come ‘98 The Mummy, Episode 1, The Matrix ’99 Hollowman, Perfect Storm ’00 Pearl Harbor ’01 How do you do it? Design Post- Post- Design Modeling Animation Lighting Rendering Design Modeling Animation Lighting Rendering Production Production “Typical” or Traditional pipeline One of the most important pieces Divides tasks Deciding what animation is to be Variants exist made Modeling Animation Post- Post- Design Modeling Animation Lighting Rendering Design Modeling Animation Lighting Rendering Production Production What are the objects? Animate: to bring to life What do they look like? Making things move How do they move? 5 Lighting Rendering Post- Post- Design Modeling Animation Lighting Rendering Design Modeling Animation Lighting Rendering Production Production Making choices in how things look Let the computers color the pixels Term is a “Pixarism” The compute intensive part Catch-all for lots of appearance design Post-Production Why focus on motion? Post- Design Modeling Animation Lighting Rendering Production It is the heart of animation It’s the most unique aspect of animation Put the pictures into final form It’s the thing we have the least experience with It’s the thing I am most interested in What is a character? (for the purposes of motion) What parameters? Some “object” (geometry) It depends! Configuration or Pose given by a set of numbers Parameters Enough controls to be expressive Control knobs Process to (or draw) Few enough to be easy geometry given parameters Articulation: define how parameters drive geometry Standard methods for gross motion Anything goes for details 6 What are those parameters? Fortunately, we don’t care How do we model a human? about details Humans are quite “Gross Body Motion” complex… Overall movement Small details hidden Under clothing Under simplified drawing models View from far enough away Chains of rigid segments Animation Apreciation 101 Abstractions Brilliance (Sexy Robot) Robert Abel and Associates, 1985 Early motion capture Early computer graphics look (chrome) Final Fantasy Square Studios, 2001 206 bones, 206 bones, 53 bones Realistic, animated, human characters muscles, fat, complex joints Kinematic organs, joints Hollowman clothing, … Sony Imageworks (effects), 2000 Complex human models, terrible dialog Abstractions vs. Reality Abstraction of Human (skeletons vs. humans) Motion Representation of complex human structure with varying degrees of simplification Simple Pin Joint Question of Approximating DOF’s Some number of connected, rigid pieces (usually) Complex tendon and Kinematic joints bone system 7 What is a motion (2) Why is this so hard? A motion maps times We are good at looking at motion! to configurations Motion is very expressive m(t) ∈ℜ ⇒ ℜn Mood, activity, personality, … Vector-valued, time- varying signal But those attributes are subtle Representation comes from creation What makes a motion sad? Realistic? typically interpolation We lack vocabulary may not be convenient for editing Talk about motion with metaphor signal (p) Time (t) Three main ways to make Creating Motion by Hand: motion Keyframing Create it by hand Skilled animators place “key” poses Compute it Computer “in-betweens” Capture it from a performer Requires incredible amounts of talent But can be done extremely well Re-use an existing motion (don’t make it at all) Verdict: Produces the highest quality results, at a very high cost Computing Motion: Procedural and Simulation Atlanta in Motion Define algorithms to create motions Ad-hoc rules, or simulate physics Physics provides realism But how do you control it? Verdict: Good for secondary effects, not for characters (yet) 8 Computing Motion: Baraff Horse Procedural and Simulation Define algorithms to create motions Ad-hoc rules, or simulate physics Physics provides realism But how do you control it? Verdict: Good for secondary effects, not for characters (yet) Motion Capture and Performance Animation Spacetime Swing Use sensors to record a real person Get high-degree of realism Which may not be what you want... Possibility for real-time performance Verdict: Good for realistic human motions. Scary to animators. Motion Capture and DD Ghosts Performance Animation Use sensors to record a real person Get high-degree of realism Which may not be what you want... Possibility for real-time performance Verdict: Good for realistic human motions. Scary to animators. 9 Motion Capture Technology: Motion Capture Technology: Optical Tracking Video User markers and special cameras An interesting and open problem… Tracking + Math Limited information But seemingly enough Problem can be arbitrarily hard Or easy – if you make assumptions Video is surprisingly bad So now you have motion... Problem: Motion is Specific Transform Motion to new uses Specific Action Specific Character different sized hand is character not here doesn’t fit Edit motion to Retarget motion to meet new needs new character Retargetting Motion to Transformation Basics New Characters Change what isn’t important, retain what is Goal: Hard to define what is important one motion, high-level properties a cast of motion specific characters Stick to what’s easy to define Similar geometric constraints structure signal characteristics framework for better metrics later 10 Transformation as Constrained Optimization Spacetime Constraints Find a motion that… 1. Meets any specific requests 2. Keeps any specific characteristics of the original 3. Is as similar as possible to the original Naturally posed as constrained optimization Consider all constraints simultaneously subject to meeting the constraints (1 and 2) NOT frame at a time minimize