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Introduction
* The term computer animation refers to anytime sequence of visual changes in a
scene.
* In computer generated animation, various transformations, along with variations in
object color, transparency or surface texture are displayed with time variation.
* We can also produce computer animations by changing lighting effects or other
parameters and procedures associated with illumination and rendering.
* Rendering is generating an object from one model by means of computer program.
Design of animation sequences
* An animation sequence is designed with the following steps:
> Storyboard layout
> Object definitions
> Key frame specifications
> Generation of in between frames
Storyboard layout:
* It is the outline of the action. It defines the motion sequence as a set of basic
events that are to take place .
* Depending on the type of animation to be produced, the storyboard could consist
of a set of rough sketches or it could be a list of the basis ideas for the motion.
Object Definition:
* Each object participating in the action is given object definition, such as terms of
basic shapes, such as polygons or splines.
Frame:
* It is one of the many single photographic images in a motion picture. The
individual frames are separated by frame lines. Normally, 24 frames are needed for
one second of film.
Key frame:
* A key frame in animation and filmmaking is a drawing that defines the starting
and ending points of any smooth transition.
Key frame:
* A sequence of key frames defines which movement the spectator will see, but the
position of the key frames on the film, defines the timing of the movement. 2 or 3
key frames can be present for a span of a second.
In between:
* It is a process of generating intermediate frames between 2 images to give
appearance that the 1st image evolves smoothly into the second image. In –
betweens are the drawing between the key frames which help to create the illusion
of motion.
* Film requires 24 frames per second and graphics terminals are refreshed at a rate
of 30 to 60 frames per second.
* Apart from above 4, the other tasks required are:
> Motion verification
> Editing
> Production and synchronization of sound track.
General computer animation functions
* Animation packages, such as wave front, provide special functions for designing
the animation and processing individual objects.
* Some steps included in the development of animation sequence are
> Object manipulation and rendering
> Camera motions
> Generation of in betweens
* One function available in animation packages is provided to store and manage the
object database (object shapes and associated parameters are stored and updated in
the database)
Other object functions include:
> Object motion generation (2D or 3D transformations)
> Object rendering
* Another to identify visible surfaces.
* One function to simulate (observe) camera movements:
> Zooming
> Panning (rotating horizontally or vertically)
> Tilting
Raster Animations
* On raster systems, we generate real – time animation in limited application using
raster operation.
* Such as 2D or 3D transformations on objects.
* We can also animate objects along 2D motion paths using the color – table
transformation.
* The pixel values at successive positions along the motion path of an object are
stored in color – table and the pixel at 1st pixel is set on, we set the pixels at the
other object positions to the background color.
Computer Animation Languages
* A general – purpose language, such as C, LISP, Pascal, or FORTRAN, is often used
to program the animation functions.
* Animation functions include a graphics editor, a key – frame generator, an in –
between generator, and standard graphics routines.
* A graphics editor allows us to design and modify object shapes.
* A typical animation specification is scene description. It includes where to position
objects, light sources, camera parameters, etc.
* Another standard function is action specification, that involves the layouts and
motion paths for the objects and camera.
* Key – frame systems are specialized animation languages designed simply to
generate the in – betweens. Also explains about degrees of freedom of an object.
* As an example this arm can have a total of 12 degrees of freedom.
* The human body, in comparison, has over 200degrees of freedom.