Lecture 1: introduction

Transcription

1 Lecture 1: introduction

2 PhD in Computer Science, MIRALab, University of Geneva, First post-doc, HCI Group, EPFL, Lausanne, Second post-doc, Institute for Media Innovation, Nanyang Technological University,

3 (Expressive) Character animation Facial animation Body gestures/emotions Gaze behavior Motion synthesis Multi-character interactions Virtual humans in VR and (Serious) Games Social robots and AI

4 Christyowidiasmoro (Chris) PhD Student (He will give the motion capture and motion synthesis lectures) Guillermo Ibañez de Aldecoa Marin (GMT Student) (Ask questions for help at the mocap lab)

5 Introduction to basic techniques in Computer Animation Motion capture & synthesis, facial & body animation, Introduction to research topics Giving presentations Reading and evaluating research papers Writing an essay about an animation topic Hands-on experience with motion capture Short animation movie production

6 Grading: Presentation (P) Animation movie (M) (and an Oscar for the winning movie ) Essay (E) Final grade = 0.3*P + 0.3*M + 0.4*E Condition: E >= 5

7 Attendance of the sessions is overall mandatory, but.. You are allowed to skip 2 lectures (by the teachers) and 2 lectures with presentations (by the students). The re-visit to the mocap lab on 25th May is optional. Attendance to the first motion capture visit, previz movies and movie festival is mandatory

8 Papers/presentations: Papers are presented in teams of two Multiple presentations per session (2 or 3) minutes per presentation divide slides over team members 10 minutes evaluation/discussion Last slide should contain 2-3 discussion points Audience should read the papers before the presentation Evaluation forms Send your slides to me one week in advance for feedback/or ask for an appointment to discuss the slides (if necessary)

9 Presentation should discuss the contents of the paper What is it about, what is the contribution, what are the drawbacks of the proposed method Some of the papers are older papers that are important for understanding an animation topic Refer to the future papers to show how the topic evolved Some of the papers will be based on rather recent techniques Refer to the previous papers to show how the topic started

10 Presentations will be evaluated by all using a grading and evaluation form. Content Visual aids Delivery Ability to answer questions Presentation grade will be given to you the next session.

11 Introduction Background Paper content Contributions of the method Drawbacks of the method Conclusion Discussion points

12 Preparing the presentation Read the paper thoroughly Read a few of the background papers to place the research or refer to future work to show how the research evolved over years Identify advantages, drawbacks, and discussion points Collect images/movies Contact the author in case of specific questions!

13 Do a test-drive at home to check the presentation is not too long or too short Please make sure that your movies work properly on your laptop! You may also use the computer in the lecture room instead, but check that your presentation works as it should!

14 To be done in teams of 4-5 Assignment: short animation movie Make a storyboard and a previz movie Record the animations in the mocap lab Animate one or more characters and make a nice rendering Tools: Vicon Blade, MotionBuilder, Maya, 3dsMax, Blender, Unity, Unreal Engine We have a number of links for 3D Models Look on the Internet for additional resources

15 Planning of the motion capture lab visit BBG building, room K62 (basement) 4 May: Introduction to motion capture lab (Chris and Guillermo) 25 May: Re-visit motion capture lab (Optional: if you have any questions) We will have a motion capture reservation schedule for each team. If you need extra hours, send an to me. If you need help for the mocap assignment, send an to Guillermo. Show previz movies! (30 May) Show movies during last session! (29 June)

16 There will be two external experts (one industry-oriented) Criteria: Quality & complexity of animations Quality & complexity of rendering Story (engaging, fun..) Use of other supportive media (music, audio)

17 Essay: Between words, including references Can be on any topic related to animation Motion capture Motion synthesis (graphs etc.) Facial animation Hand animation Animation & interaction (gestures etc.) Animation & emotions Skinning Automatic Rigging There are two examples on the course website Attention: they are good but not perfect

18 Choose at least three papers with different but related techniques Describe the techniques in your essay, compare them in terms of pros and cons, advantages and limitations Show what the possible application areas are Describe the techniques in enough depth Write the essay in your own words! You can start writing it anytime during the course. The early the better! Deadline 29 June until midnight! 0-24 hours late: 1 point deduction hours late: 2 points deduction >48 hours late: submission rejected

19 You can do a retake essay If you did all the assignments If your grade is at least 4 You may improve the essay you originally handed in, taking into account the feedback from the teacher or choose a new topic and write an essay about that.

20 Computer Animation, Rick Parent Siggraph and Eurographics tutorials Research papers

21 Check the website regularly for updates: For all other questions, ask during the lecture, after the lecture or send me an !

22 Animate means to give life to according to Merriam-Webster Based on Latin word anima, meaning breath or sprit E.g. Animal Animation is the process of making the illusion of motion and the illusion of change by means of the rapid display of a sequence of images that minimally differ from each other. Pixar in a Box at Khan Academy -

23 Computer-based computation used in producing images intended to create the perception of motion Algorithms and techniques that process 3D graphical data Object s position and orientation But also shape, shading parameters, texture coordinates, light source parameters, camera parameters

24 Computer-assisted animation 2D & 2 1/2 D Inbetweening Inking, virtual camera, managing data, etc. Beauty and the Beast, Antz Computer generated animation Low level techniques Precisely specifying motion High level techniques Describe general motion behavior Toy Story, Frozen, Inside Out, Shrek

25 Low-level techniques Shape interpolation Helps the animator fill in the details of the motion given enough information Animator has a fairly specific idea of target motion High-level techniques Generate a motion given a set of rules or constraints Object motion is controlled by a model/algorithm Fairly sophisticated computation, such as physically-based motion

26 Very low-level: animator colours every pixel individually in every frame Very-high level: tell the computer make a movie about a dog Challenge lies in developing tools that allow animators to animate on different levels

27 Special Effects (Movies, TV) Video Games Virtual Reality Simulation, Training, Military Medical Robotics, Animatronics Visualization Communication

28 Artistic animation Animator crafts the motion Keyframing and interpolation Data-driven animation Digitizing live motion and applying to 3D objects Motion capture Procedural animation Computational models of motion By setting initial conditions for physical and behavioral simulation

29 while (!finished) { UpdateEverything(); DrawEverything(); } Interactive vs. Non-Interactive Real Time vs. Non-Real Time

30 Animation tools: Maya 3D Studio Max MotionBuilder Blender Game/graphics engines: OGRE3D Unity Unreal

31 Applications of animated characters Health Analyzing walking styles Analyzing muscle activations Analyzing joint movement limits Ergonomics Usability of devices Measuring comfort Safety Simulated worlds for crisis management Entertainment Games, movies

32 Different levels of character motion

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34 Siggraph (ACM Transactions on Graphics) Eurographics (Computer Graphics Forum) ACM/Eurographics Symposium on Computer Animation Motion in Games Computer Animation and Social Agents IEEE Computer Graphics and Applications IEEE Transactions on Applied Perception (perception of animation) Computers & Graphics (Elsevier) Computer Graphics International (Visual Computer) Industry-oriented: Game Developers Conference, FMX

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36 Eye/brain assembles images and interprets them as continuous movement Persistence of vision: sequence of still images shown at a fast enough rate to induce sensation of continuous imagery Eye retains visual imprint once stimulus is removed positive afterimages

37 Persistence of motion is the sensation that something is moving. It is not the same as the persistence of vision. Motion is perceived but not necessarily due to a succession of still images, e.g., lights on a movie marquee

38 Phi phenomenon is the optical illusion that when two lights are rapidly turned on and off in succession something appears to move backwards and forwards between them while the lights stay stationary Beta Movement is an optical illusion whereby a series of static lights on a screen creates the illusion of a smoothly flowing scene. Max Wertheimer, 1912 One of the co-founders of Gestalt psychology

39 Flicker: the image flickers when persistence of vision does not occur When the perception of continuous imagery fails to be created, the display is said to flicker. Critical flicker frequency is the rate at which the images must be shown in order to maintain persistence of vision. Different things that affect it are: room lighting, viewing distance, etc. The critical flicker frequency determines the lower bound on the playback rate.

40 Lower bound: Critical flicker frequency: lower limits for establishing the perception of continuous imagery Playback/refresh rate: number of images displayed per second Upper bound: Upper limits the eye can perceive motion, if an object moves too quickly Motion blur: the receptors in the eye will not be able to respond fast enough for the brain to distinguish sharply defined, individual detail and motion blur occurs.

41 In a sequence of still images, motion blur is produced by a combination of the object s speed and the time interval over which the scene is sampled. movement changes the color of a pixel as a function of time. If the temporal frequency of a pixel s color function is too high, then the temporal sampling can miss important information.

42 Sampling rate 0 1/30 sec Reality 0 1/60 sec 1/30 sec

43 Entire motion of the object is missed because sampling rate is too low to capture the fast motion of the object Displaying a rapidly moving object by a single instantaneous sample results in jerky motion similar to that of live action under a strobe light (and this is often called strobing).

44 Conventional animation has developed its own techniques for representing fast motion. Speed lines can be added to moving objects Objects can be stretched in the direction of travel, or both speed lines and object stretching can be used

45 Two important rates: Playback/refresh rate: number of images displayed per second Related to flicker Sampling/update rate: number of distinct images that occur per second How jerky the motion will appear e.g. Saturday morning cartoons have a sampling rate of 6 frames per second (fps) but each image is repeated five times, so the playback rate is 30 fps.

46 Film Imax NTSC TV PAL TV HDTV Computer 24 fps 48 fps 30 fps (interlaced) 25 fps (interlaced) fps >60 fps History of frame rate:

47 Persistence of vision: discovered in the 1800s. Zoetrope Flipbook Thaumatrope

48 Eadweard Muybridge Animal Locomotion Animals in Motion The Human Figure in Motion

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50 End of the 19 th century introduced moving image by using a projector. Magic Lantern and shadow puppets

51 Zoopraxiscope (zoetrope + projector)

52 Kinetograph/kinetoscope (Edison and Dickson, 1888) First motion picture camera/viewer

53 Cinematograph Lumiere brothers, 1895 Arrival of a Train at La Ciotat, 1896

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55 Animation movie pioneers J. Stuart Blackton (smoke effect, 1900) First animated cartoon in 1906 Used a chalkboard for drawing and erasing frames Emile Cohl (Fantasmogorie, 1908) Winsor McCay (Little Nemo, 1911) Each image redrawn on rice paper and then filmed

56 Major technical developments by John Bray (1910): compositing multiple layers of drawings into a final image (celluloid) using grayscale Drawing background on long sheet of paper for panning Max Fleischer (Betty Boop), Walter Lantz (Woody Woodpecker) Fleischer patented rotoscoping in 1915

57 First animated character: Felix the Cat (Otto Messmer) in early 1920s Disney came around end 1920s, introducing a number of innovations Storyboards Pencil sketches for reviewing motion Multiplane camera Using sound & colour

58 Move scene layers move independently of camera Six directions of movement for each plane

59 Powerful tool: More effective zoom Move foreground image to the side Parallax effect Moving planes at different rates Adding depth cues Blur the images on more distant planes Introduce motion blur by fast moving planes

60 Sound was added for the first time in Steamboat Willie (1928) Disney promoted idea that mind of the character was the driving force of the action Analysis of real-life motion

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62 Computer animation is often compared to stop motion animation Puppet animation Willis O Brian (King Kong) Ray Harryhausen (Mighty Joe Yong, Jason and the Argonauts)

63 Claymation Sand animation Physical object is manipulated, image captured, repeat

64 Preliminary story Story board Detailed story Key Frames Test shot Pencil test Inbetweening Inking Coloring

65 Conceptual Design Production Design Modeling Materials & Shaders Rigging Blocking Animation Lighting Effects Rendering Post-Production

66 John Lasseter, "Principles of Traditional Animation Applied to 3D Computer Animation", Computer Graphics, pp , 21:4, July 1987 (SIGGRAPH 87).

67 Squash and Stretch - defining the rigidity and mass of an object by distorting its shape during an action Timing and Motion - spacing actions to define the weight and size of objects and the personality of characters Anticipation - the preparation for an action Follow Through and Overlapping Action - the termination of an action and establishing its relationship to the next action Slow In and Out - the spacing of the in-between frames to achieve subtlety of timing and movement Arcs - the visual path of action for natural movement Exaggeration - Accentuating the essence of an idea via the design and the action Secondary Action - the action of an object resulting from another action Personality in character animation is the goal of all of the above.

68 Lasseter translated traditional principles of animation to computer animation (1980s) Lasseter is conventionally trained animator Worked at Disney before going to Pixar Chief creative officer Pixar Many celebrated animations Toy story, Wall-e, Frozen, Inside Out

69 Pixar Luxo Jr. (1986) Red's Dream (1987) Tin Toy (1988) first computer animation to win an Academy Award Knick Knack (1989)

70 In Research labs (from 1970s) New York Institute of Technology (NYIT) Gumby (Presented at SIGGRAPH '84 & '85 Electronic Theatres) Still frame from Gumby animation by Hank Grebe and Dick Lundin, 1984.

71 University of Utah Films on walking and talking figure Animated hand and animated face (Ed Catmull (president of Pixar now), 1972) (Fred Parke, Talking face, 1974) University of Pennsylvania Human figure animation (Norm Badler, 1975) MIRALab, Geneva Virtual Humans (Daniel & Nadia Thalmann, 1980s)

72 Ed Catmull: President of Pixar and Walt Disney Animation Studios

73 Future World (1976) Star Wars (1977) Tron (1982, MAGI) Supposed to look like a computer The Last Starfighter (1984) Use CG in place of models Willow (1988, ILM) Morphing video First digital blue screen matte extraction The Abyss (1989, ILM) Lawnmower man (1992, Xaos, Angel Studios) Hollywood s view of VR

74 Jurassic Park (1993, ILM) Forrest Gump (1994, Digital Domain) Insert CG ping pong ball Babe (1995, Rhythm & Hues) Move mouths of animals & fill in background Toy Story (1995, Pixar & Disney) First full length fully CG 3D animation

75 Reboot (1995, Limelight Ltd. BLT Productions) Similar intention of inside computer First fully 3D Sat. morning cartoon Babylon 5 (1995) Routinely used CG models as regular features Simpsons (1995 PDI)

76 Final fantasy (2001) Fully 3D simulated environment Lord of the Rings ( ) One of the first movies using crowds (Massive) Avatar (2009) Benjamin Button (2008) Prometheus (2012)

77 L.A. Noire HellBlade Senua s Sacrifiece Ready Player One Real Time Mike

78 Milestones of the animation industry in the 20th Century stones6.php3 Brief History of NYIT Computer Graphics Lab Rick Parent nimation/rick_parent/intr.html

79 Animation basics on Wednesday (May 2 nd )