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Lecture 6 Animation

Lecture 6 Animation. Learning Outcomes By the end of this module, you will be able to explain: captured animation The meaning of image sequences Digital Cel & Sprite Animation Key Frame animation Motion graphics 3-D animation Virtual reality VRML

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Lecture 6 Animation

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  1. Lecture 6 Animation

  2. Learning Outcomes • By the end of this module, you will be able to explain: • captured animation • The meaning of image sequences • Digital Cel & Sprite Animation • Key Frame animation • Motion graphics • 3-D animation • Virtual reality • VRML • QuickTime and VR

  3. Introduction • Animation is creating moving pictures one frame at a time, • it also means the created sequence. • Started on 1890's • Cel animation • fixed background - Homer's living room • cel, drawn on transparent paper - Homaer's image • More complexity is created by overlaying more than one cel • long background for creating travelling through scene • Other means of animation • painting directly on the film, • sand or oil paint on glass • chalks on paper or card • back or front lit cut-outs • 3-D animation; stop motion animation • moving objects carefully between shots • malleable modelling material - clay animation • Hybrid animation - mixing cell with 3-D, Animation + live footage (stuart little) • All these have their digital counter parts 

  4. Captured Animation • Video camera connected to computer • Captures each frame of animation, to the hard disk, from: • paper, cel, 3-D Set,... • digital version of a single frame can be stored • This frame grabbing is provided by editing programs • This can be used for • checking the shot • capture a frame • To be stored as a still picture OR • Appended to AVI or QuickTime movie • Then next frame is grabbed • Unsatisfactory frames can be deleted to produce the required sequence • Digital animation can be combined with traditional to produce hybrid sequence • QuickTime allows for storing the frames as sequentially numbered image files • This is useful for manipulating individual images separately using image editors • However, managing of a collection of image files can be very complicated

  5. Captured Animation • Scanner can be instead of camera • Digital still camera can also be used • In both of these cases you are allowed to: • Work with higher resolution images • Larger colour gamut • Graphics editing program can be used to: • make your artwork • save your frames as individual images • Sequence of image files imported into video editing application to create the movie • Naming must conform with some specific conventions: • In Premiere *.001, *.002, *.003, ..

  6. Captured Animation • Movie editing programs provide support to modify individual frames. • For example, Painter: • Supports frame stack--a set of images with same dimensions & colour depth • Works on 4 ghost images

  7. Captured Animation • Computer programs help the animator in: • recording sequence of operations as a macro or script to: • draw repeated elements • apply filters to many frames • Also, framestack can be used to create animation by progressively altering one single image • Rotoscoping can also be implemented to: • create animation that accurately reproduce natural movement. (Any example?) • GIF animations are implemented by storing many frames in a single file • Painter, Premiere and Flash can produce animated GIF files • Also ImageReady and Fireworks can be used. • GIF file is played from the HD by the CPU • Require no plug-in • Sound not possible, only 256 colours and little compression. • Not for realistic use, but for stylised changing images (Example?) • Worst animations appeared due to ease of production. • QuickTime using video format is the standard for animations with sound  

  8. Digital Cell & Sprite Animation • Layers allow to create separate parts of a still image • A person • And a background • Animation can be created by keeping the background and changing the person • Addition of more static images produces depth illusion • The moving  object may only need reposition or transformation • Globe moving in stars background • This is called Sprite animation • Objects are called Sprites  • faces can also be used - for creating walking man • QuickTime support sprite tracks • key frame samples - most of the data • override samples - changed properties • can be generated by a program  • properties can be changed by user interaction - games

  9. Key Frame Animation • Most powerful web animation is Shockwave Flash - supports vector & bitmapped graphics • Interpolations (tweenings in Flash)) are more easily applied for vector graphics • Flash - uses timeline • Flash usesstage (a sub-window) used to: • Create frames from objects • objects are hand drawn OR • pictures - jpg or png • preview animations • Objects can be stored in a library as symbols • Transformations can be applied on these symbols • Flash contains vector graphics drawing toolbox • Objects can be moved (motion tweening) along a path (of any shape) drawn on a layer • Flash supports shape tweening and complex animations • Flash uses easing in an easing out • Beizer curves can be used to ease abrupt velocity change • Flash also support scripting language (ActionScript) for user interaction • Native format of flash files is SWF (vector animation format) which contains: • Definitions of symbols, and • Control Items; instructions

  10. Motion Graphics • Simplest Animations can be made by repositioning layers of bitmapped images (cell animation) by: • Dragging them • Entering coordinates and interpolating between them • Combining layers and adding effects and time varying filters • AfterEffects supports both interpolations: • Linear and • Beizer • Temporal Interpolation is set of value graph for the property • The figure illustrate the frog velocity • To prevent gliding effect - separate parts of the frog should be put on separate layers 

  11. Motion Graphics • The figure shows time-varying Guassian blur in conjunction with varying brightness • Beizer interpolation is used for smooth fade-up • Adding temporal dimension to objects introduces the application of new effects

  12. 3-D Animation • 3-D models are a collection of numerical quantities • These quantities represent Object's: • Position in space • Rotation • surface characteristics • Shape • Numbers also represent: • Light source: • intensity • direction • Camera: • position • orientation • Therefore to animate in 3-D you have to: • Setup & render 1-st frame • make changes to parameters • render the next frame • You need interpolation to do these calculations • 3-D motion paths are Beizer splines

  13. 3-D Animation • Simple 3-D animations are easy to generate with dedicated software • Realistic 3-D animations require huge resources of: • CPU power • memory • software • Skilled personnel • 3 factors make 3-D animation hard: • Human difficulty in visualising 3-D objects • Therefore 4-D(also time) has to be visualised in 2-D screens • 3-D rendering (ray-tracing) requires immense processing even for single frame • You have to do all that for at least 12 frames/second • Behaviours of objects used in animation: • one object points to another • one object tracks another • following laws of physics - falling objects, acceleration, speed,..

  14. 3-D Animation • Kinematics: • motion study without reference to mass or force - human arm movement • Kinematics constraints - certain ways of moving the arm • Inverse Kinematics- moving foot to a step; work from step position • from effect to cause • Does not work in straightforward manner - how many ways can you touch you nose tip with your 1-st finger • Some 3-D animations can be done effectively using simple interpolation of object properties • Most successful - • Animation produced by interpolating between key frames • Similar to after effects • Animating a camera to obtain 'fly through' • Animating a camera to follow objects motion • Examples • terrain modelling • Moving clouds • Storm gathering - through colour and density manipulation • Rainbows - appear & fade • fog swirl & disappear

  15. Virtual Reality • Head-mounted dsiaplays • data gloves • High cost of the hardware limited its usage • Two VR technologies deserve mentionin • VRML • Created 1994; text base language • allows 3-D  objects & scenes to be described by a programming language • VRML 1.0 embedded hyperlinks in scenes • VRML 2.0 supports interactivity (ISO standard in 1997) Specifying objects in terms of geometry - Cylinder, cube,.. • Scenes can be lit in different ways • Object described by a grid constructed from points • It is more than modeller • Provides interactivity • incorporation in the web • The way objects are displayed • Once VRML file is downloaded the plug-in (or dedicated Browser), VRML allows the user to explore the 3-D world it describes • VRML must be rendered in real-time using 3-D accelerator • cards

  16. QuickTime VR - QTVR • Basic VR experience • Two types of VR movies: • Panoramic movies - 360 degrees of the scene • Object movies - examine object from different angles • Both contain hot spots -Active areas (links) • go through door • Generated from Bryce • made from photos • special rotating rig for camera • Productions can be combines with audio & video • can be viewed by QuickTime software • VR and QTVR implements VR with out special interface expensive devices

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