UNIT VI: Animation

Uses of animationtypes of animation.Principles of animation, techniques of animation: Onion skinning, motion cycling, masking, flip book animation, rotoscoping and blue screening, color cycling,

morphing, animation on the web, 3D animation, Creating animation.

AnimationAnimate – to give life to

Rapid display of images in succession fools the eye into perceiving continuous motion due to 'persistence of vision'

It deals with graphics drawn by individuals either by hand or by using software.

It also involves a model which is changed by small amounts oat a time and then repeatedly photographed – called stop motion animation.

Animation sequences are created by 2 types of artists : 1. lead artists / experts (who draw frames where major changes take

place in a sequence called KEY FRAMES)2. Assistants draw a number of frames in between the key frames, a

process called TWEENING.

Key frames and tweening

Important / key frames are drawn by experts.

Intermediate frames are drawn by assistant animators. This process is called tweening (in between).

Animators find 18 increments of movement projected at 24 frames / sec give a life like result. Practically they draw nice motion increments and then photograph each frame twice.

Computers have made things easier.

Uses of animation

Entertainment Industry

Computer Games

Education

Industrial and Scientific applications

Types of Animation

1. Cel Animation

Comes from Celluloid and refers to the transparent piece of film that is used in hand drawn animation. Animation cels are generally layered one on top of the other to produce a single animation frame. Layering enables the animator to isolate and redraw only the parts of the image that change between successive frames.

Types of Animation

2. Path Animation (Sprite Animation)

Here animation does not exist as a collection of frames but rather as mathematical entities called vectors stored by the animation program.

It involves an image or a collection of images together called a sprite, that moves as an independent object like a flying bird, a rotating planet etc. The sprite moves along a motion path typically curved called splines.

The spline passes through a series of anchor points. Usually path animation takes up less disk space compared to cel animation.

Types of Animation

3. 2D vs 3D animation

2D animation programs do not consider depth of object and depict them on flat (X-Y direction) surfaces.

3D animation monitors objects by considering modeling, rendering(process of generating an image from a model, by means of computer programs) and adding surface properties, lighting and camera motions.

Principles of animation

1. Squash and Stretch

Example : Bouncing ball. An object that changes the shape as it strikes the ground and reverts back to the original shape as it rebounds; gives a good effect.

2. Anticipation

“Prepare to act before we act” - animation should make this clear.

3. Staging

To arrange things in each frame so that the action is clear and easy to see. Staging means to give emphasis to main characters and to integrate them with the background.

Principles of animation

4. Follow-through and overlapping actionFollow through is the complement of anticipation. Eg – throwing a flying disc action makes the arm move in a long continuous arc even after the disc has been thrown. Anticipation and follow through combine in overlapping action.

5. Slow in and slow outA good effect of a bouncing ball would be to see it slow down when it is rising and momentarily stop at the topmost point.

6. ArcsThe overall movement of characters in an animation should follow an arc as well.

7. Secondary ActionEach part of a character might not move at the same rate.

Principles of animation

8. TimingSpeed of action is an important way to show a character's intent.

Rapid movement for emergencies and slow movement implies deliberation. Timing also indicates weight.

9. ExaggerationExaggerating the important elements makes them stand out and

brings them closer to the viewer.

10. AppealCharacters that are visually intriguing are more likely to hold an

audience's attention than characters whose appearance is predictable or mundane.

techniques of animation

1. Onion Skinning

It is a drawing technique borrowed from traditional cel animation that helps the animator create the illusion of smooth motion. It is an easy way to complete sequence of frames at a glance and to see how each frame flows into the frames before and after.

techniques of animation

2. Motion Cycling

Human motion such as walking, running and flying is a repetitive action that is best represented by a cycle.

3. MaskingA mask in a computer program is in a sense a model of the plastic masks – it protects part of a frame from effects of other editing tools. This technique can be used to make an animated object move behind the

protected area. Suppose the frame of the TV is masked, so that the scrolling text do not appear in front of the frame, but is only visible within the TV screen.

Techniques of animation

4. Adding Sound

Background music can evoke emotions. Sounds that arise from the actions being viewed can clarify what is happening and create an effect of realism. We can have synchronous and asynchronous sound.

5. Flip book animationIt is a book with a series of pictures varying gradually from one page to

the next so that when the pages are turned rapidly, the pictures appear to animate, simulating motion or some other change.

6. Rotoscoping and BluescreeningRotoscoping is an early animation technique which enabled animators

and video editors to trace the contour of objects on each frame of an animation and video sequence to create a silhouette called a matte.

Rotoscoping and Bluescreening

The traced contour is then replaced by something else to produce a special visual effect. For example : Original Star Wars movie which showed a glowing lightsaber effect by creating a matte based on sticks held by actors.

Bluescreening is a technique for shooting live action against a even coloured blue background and then replacing the background by another image. Blue is normally used for people but if scene itself contains objects with blue colour, then other colours like green and orange are used.

Techniques of animation7. Colour Cycling It allows to change colour of objects by cycling through a range of

colours. The software provides smooth colour transition from one colour to another.

8. MorphingIt is the process of smoothly interpolating between two different

images. When played back it appears that the first image gradually and seamlessly changes into the second image.

Animation on the webTypically web based animations involve computer files that must be

completely downloaded to the client machines before playback.

Limitations in use of animation on the web :1. Bandwidth2. Browser support3. Differences in platforms

Streaming technology is used in order to take care of large size of files.

Once animation has been delivered to the user, the user must have the proper helper application or plug in to display the animation. Several formats exist today likeGIF animation (extension to GIF specification)QuickTime Animation (based on QuickTime movie format)Shockwave animation (based on Macromedia Director / Flash file format etc)Java Animation (based on Java programming language)

Macromedia Director Macromedia's Shockwave technology for Director was one of the first plug ins for browsers. Director is a popular 2D animation and interactive multimedia authoring tool. To be played via the browser, the Director movie must be saved in the Shockwave format which uses the DCR file extension.

Macromedia FlashMacromedia Flash animation sequences can be saved in the Shockwave format which uses the SWF extension. SWF is an open format which means that anyone can implement players or application software to support SWF without paying royalties.

1. Shockwave Format

In Client Pull animation, an HTML page gives the browser instructions to request and load another document automatically which contains the next frame of the animation. This feature is like a slideshow.

2. Client Pull Animation

3. Server Push AnimationA server push animation requires a CGI (common gateway interface) script that tells the server when to automatically serve a new document or image. So the HTML tag gives directions to a CGI script that runs the animation instead of retrieving the image file, itself.

3D animation

Creating 3D animation involves a number of steps :

1. Modeling – creating 3D objects from 2D shapes through lofting (moving the object along a specific direction) and lathing (rotation of the object about its axis to create 3D shape).

2. Surface Texture – imparts a realistic appearance to the 3D models by applying textures over the object surface.

3. Lighting – involves placing the lights in the scene by specifying their intensities, direction and colour. The direction of shadows are also considered.

4. Camera – the placements determine how the scene should look like. Movement of camera can be used to produce zooming and panning effect.

3D animation ....

5. Animating – it involves the creation of key frames and tweening to produce intermediate frames. Tweening – the drawing of intermediate frames between key frames drawn by assistant animators.

6. Rendering – it produces the final output file and needs specifying the file type, frame size, frame rate etc.Rendering algorithms are :1 Ray casting algorithm2 Shading algorithm3 z buffer algorithm4 Ray tracing algorithm5 Polygon algorithm6 Aliasing

Creating animation

For producing a one hour film, 108000 frames are required. The computer serves as an assistant to the human animator.

Interpolations Camera Animation

Parameter Curve Editing Animating Lights and surface properties.

Hierarchical Animation

Inverse Kinematics (IK) Shape Changes

Motion Paths