1. Multimedia object types: animation
ISMT multimedia Dr Vojislav B Mišić

2. Animation Technically, similar to video – a sequence of still images
Images created artificially, as opposed to video (which presents something happening in the real world, maybe retouched)
Why? Because it is a good (and sometimes less expensive) way to show/say some things

3. What we are going to talk about?
Cel (and flipbook) animation
Sprite, path, vector animation
Key frames and tweening
Character animation
2D vs. 3D
… and other things

4. Flipbook animation
displaying a sequence of graphic files (e.g., a slide show)
problem: takes too much time (especially over the Internet)
solution: some form of compression (we will discuss this in more detail later)
compression techniques are usually proprietary (different type of images!)

5. Cel animation
animation created by a sequence of still images (as always)
different characters, objects, backgrounds overlaid to obtain the final image
final image is shot frame by frame
changes are made only to objects which move
multiplan camera (Disney): distance between layers in order to create an illusion of depth

6. Sprites and Paths
sprite: a part of the animation which moves independently of the rest
anything can be a sprite: ball, animal, human, …
a sprite can be attached to a path (or vice versa), so that successive sprite positions are located on a path
sprite can animate in-place, or move along a path, or both

7. Splines and Vectors paths can be linear, but that is unrealistic
more often, paths follow a spline curve
watch for gravity!
example: mixed feelings
sprites can be described as raster objects

8. Key frames most important frames are drawn first: key frames
establish the main dramatic poses,
define the flow of actions, and
create the overall graphic style of the animation

9. Tweening tweening: frames are inserted between the key frames
computer can do much of the tedious work

10. Motion interpolation Motion along an arbitrary line
Computer performs the interpolation
Special effects (rotation, resizing) can be specified along the line

11. Character animation
often the trickiest part – many simultaneous movements involved
faces are very difficult to animate
sometimes cutouts are used for body parts

12. Other design effects ease-in and ease-out velocity curves
line-of-action
secondary action and overlapping action
follow-through
hierarchical motion
exaggeration

13. Anticipation, action, reaction
Action/reaction is often anticipated before it actually happens
Sometimes aided by showing small movements immediately before the action
Reaction-recovery: small movements in the opposite direction immediately after the action
Fake: the action itself is not shown, only what happens before and immediately after

14. Kinematics
(in mechanical engineering) study of motion of rigid objects and structures
(in motion picture technology) study of motion of (rigid) objects and structures with joints
examples: men (objects) walking, running, falling down or apart
inverse kinematics: calculating the motion form predefined key positions, under the given set of constraints

15. Morphing transformation of one image into another
very popular a few years ago
a number of key points is set on both images
actual transformation is calculated on the basis of transformation (in both position and color) of key points
more key points + more intermediate steps = smoother transformation

16. Some rules to be obeyed …

17. Animated GIFs
a sequence of still images (actually GIF images according to GIF89a standard), packed for the Internet
suitable for simple animations
small size = short loading time
several tools available (including one from Microsoft)

18. Macromedia Flash Quickly becoming de facto standard
Compact export format, players
Ability to incorporate raster images as well as vector objects
Powerful 2D motion effects
Hotspots to support interactivity
More on Flash in the lab sessions …

19. 2D vs. 3D our perception of the world is three-dimensional
3D effects improve visual appearance
3D special effects can be added to 2D images (most drawing/painting programs can do it)
3D images can be generated from appropriate scene setups
… but: sophisticated applications are required

20. 3D effects adding depth to 2D images effects like extruding shadows
highlights
embossing
texturing
special lighting effects

21. Genuine 3D genuine 3D worlds rendered into 2D images
tasks in creating 3D: a brief overview according to Pixar

22. Step 1: Creating Storyboards
detailed storyboard drawings are created as the blueprint for the action and dialog
there can be as many as 3 to 4 thousand such drawings for a feature-length movie (which comes to about one drawing every two seconds or so)
they are revised many times during the creative development process

23. Step 2: Modeling
specialized animation software is used to create three-dimensional computer models of characters, props, and sets
computer models describe the shape of the object as well as the motion controls that the animators use to create movement and expressions

24. Step 3: Animation
specialized animation software allows animators to choreograph the motion in each scene by defining key frames or poses
computer automatically creates the "in-between" frames
animators neither draw, nor paint the scenes, as is required in traditional animation process

25. Step 4:
surface characteristics, including textures, finishes and colors, are added to every object in the scene
textures can simulate a wide variety of appearances
textures may be 2D images or procedural algorithms
additional properties: reflectivity, transparency …

26. Step 5:
Using "digital lights," every scene is lit in much the same manner as stage lighting
Key, fill and bounce lights and room ambience are all defined and used to enhance the mood and emotion of each scene

27. Lighting is the key Key light – the brightest
Fill light – opposite the key light, reduces contrast and shadows
Back light – reduces shadows, separates the subject from the background
Powder your nose

28. Step 6: Rendering
rendering software (Pixar's proprietary RenderMan) "draws" the finished image by computing every pixel of the image from the model, animation, shading, and lighting information
once rendered, final images are transferred to film, video, or CD-ROM

29. Summary Animation is often the simplest way to accomplish motion
If you want to go beyond what Flash can offer, be ready for surprises …