CGMB113/ CITB 123: MULTIMEDIA TECHNOLOGYCHAPTER EIGHT

MULTIMEDIA BUILDING BLOCKS IVANIMATION

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SARASWATHY SHAMINI

Adapted from Notes Prepared by:Noor Fardela Zainal Abidin

© UNITEN 2004/2005

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Objectives

At the end of this chapter, students should be able to:

• identify the terms and concept related to animation• describe how animation can be used in multimedia

systems• understand some of the common animation

techniques

Introduction to Animation• To animate can be thought of as, “to bring

to life”• Animation = An illusion of movement

created by sequentially playing still image frames with different movements at the general rate of 15 - 30 fps (frames per second)

• Animation = rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement.

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A little bit of history• The earliest form of animation is a 5,200 year old earthen

bowl found in Iran in Shahr-i Sokhta which has five images painted along the sides.

• When the bowl is spun, it shows a goat leaping up to a tree to take a pear.

• Early examples of attempts to capture the phenomenon of motion drawing can be found in paleolithic cave paintings, where animals are depicted with multiple legs in superimposed positions, clearly attempting to convey the perception of motion

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How Animation Works• Animation is achieved by adding motion to still image/object.• May also be defined as the creation of moving pictures one

frame at a time.• Few types of animation▫ Layout transition▫ Process/ information transition▫ Object movement

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This animation moves at 10 frames per second.

This animation moves at 2 frames per second. At this rate, the individual frames should be discernible

Introduction to AnimationAnimation is possible because of •a biological phenomenon known as persistence of

vision ▫An object seen by human eye remains chemically mapped

on the eye’s retina for a brief time after viewing•a psychological phenomenon called phi▫Human’s mind need to conceptually complete the

perceived action i.e. translating the action

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How Animation Works

• Combination of these two (persistence of vision + phi) make it possible for a series of images that are changed very slightly and very rapidly, one after another, to seemingly blend together into a visual illusion of movement.

• E.g. a few cells or frames of rotating logo, when continuously and rapidly changed, the arrow of the compass is perceived to be spinning.

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Still images are flashed in sequence to provide the illusion of animation

How Animation Works

•Still images are flashed in sequence to provide the illusion of animation

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How Animation Works

•The speed of the image changes is called the frame rate.

•Film is typically delivered at 24 frames per second (fps)• In reality, the projector light flashes twice per frame,

thus increasing the flicker rate to 48 times per second to remove any flicker effect.

•The more interruptions per second, the more continuous the beam of light appears, the smoother the animation.

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Traditional Animation Types and Techniques• Cel animation - The animation artist

draws or paints on sheets of celluloid film. The cels are layered over the background, then photographed frame by frame.

• Stop-motion animation. Stop-motion animation is a film technique that involves shooting one frame of film at a time. A stationary camera is pointed at the object or scene. Each frame of motion picture film is exposed individually. Between exposures, the object or scene is manipulated or changed.

• Rotoscoping - is the technique of re-drawing live-action images on paper in order to capture natural motion in one's illustrations.

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"The Lost World", 1925, animation by Willis O'Brien, one of the early masters of stop-motion.

Animation Technique: Cel AnimationMade famous by Disney 1) A series of progressively different graphics are used for

each frame of film2) Elements in a scene that might move, for example

Kluang man, are drawn on sheets of transparent material called ‘cel’, and laid over a background which is drawn separately (kampung scenery for example)In producing a sequence, only the moving elements on the cel need to be redrawn for each frame, the fixed part of the scene need only be made once.

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Animation Technique: Cel Animation• Animation is drawn between keyframes.

▫ Key frames identify the start and end of some action▫ The process of filling in the action is called

tweening.

• Tweening is a process which requires calculating the number of frames between keyframes and the path the action takes, and then actually sketching on to a cel the series of progressively different outlines.

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•This image shows how two transparent cells, each with a different character drawn on them, and an opaque background are photographed together to form the composite image.

Animation Techniques - Cel Animation

http://en.wikipedia.org/wiki/Traditional_animation

Animation Technique: Stop Motion• Miniatures three-dimensional sets are used (stage,

objects)• Objects are moved carefully between shots.• Objects may include articulate figures, whose limbs

can be repositioned, or solid figures whose parts are replaced, or substitute between shots, to produce an effect of gesture, walking, and so on.

• Plasticine may be used for objects, to be manipulated between shots to produce both natural movement, and otherwise impossible changes and transformations.

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http://wallbond.org/uploaded_images/PierceStopMotion-788581.jpg

Stop-motion animation

Computer Animation – Digital cel & sprite animation•Employ the same logic and procedural concept of cel

animation.•Objects are drawn using 3D modeling software•Objects and background are drawn on different

layers, which can be put on top of one another.• Layers allow you to create separate parts of a still

image, for example, a person and the background of a scene they are walking through – so that each can be altered or moved independently.

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Computer Animation – Digital cel & sprite animation•Sprite animation – animation on moving object

(sprite).•A set of images, called faces is associated with

each sprite.•Example, a walking man, can be created by

advancing the position of the sprite (the man) and cycling through the faces (walking motion), the man can be made to walk.

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Computer Animation – Key Frame Animation• Keyframes : ▫Are drawn to provide the pose a detailed characteristic of

characters at important points in the animation.▫Example, specify the start and end of a walk, the top and

bottom of the fall.• 3D modeling and animation software will do the

tweening process▫ It fill in the gaps between the keyframes and create a

smooth animation.▫You just set the value of frames per second (fps) for your

animation.

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Example of a claymation Example of a computer animationhttp://en.wikipedia.org/wiki/Image:Pyramid_of_35_spheres_animation.gifhttp://www.dbprescott.com/girlanim.gif

Animation Techniques – Claymation And Computer Animation

http://www.cadtutor.net/dd/bryce/anim/anim.html

Basic Concepts of Tweening

Computer Animation – Hybrid Animation•Mixing cel and 3D computer

animation.•May as well include life footage.

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Animation Techniques - Kinematics

• The study of motion of jointed structure (such as people)

• Realistic animation of such movement can be complex.

• Latest technology use motion capture for complex movement animation.

• Inverse kinematics is the process of linking objects, and defining their relationship and limits.

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http://dictionary.zdnet.com/definition/motion+capture.html

Animation Techniques - Morphing

•The process of transitioning from one image to another

•When morphing, few key elements (such as a nose from both images) are set to share the same location (one the final image).

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Animation File Formats•Windows Media files : .avi, .asf or .wmv•Apple QuickTime files: .qt or .mov•Motion video files : .mpeg or .mpg•Flash files : .swf•Shockwaves files : .dcr•Animated GIF : .gif

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Creating Animation•Use digital camera to capture each drawn frame.•Scan the drawn image/frame.•Video camera (connected through video capture

card) is connected directly to computer to capture each frame of animation on disk – let it be on paper, cel, constructed on 3D set or by any other techniques discussed.

•Software tool can help create object

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References

•Vaughan Tay, Multimedia: Making It work. 7th Edition. McGraw Hill

•S. McGloughlin, “Multimedia: Concept and Practice”, Prentice Hall, 2001

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