Animation
What is animation?
• The computer animation refers to any time
sequence of visual changes in a scene.
• In addition to changing object position with
translations or rotations, a computer generated
animation could display time variations in object
size, color, transparency or surface texture.
• Animation is used in visualization to show the
time dependent behavior of complex object e.g.
multimedia projects and web pages
Application of Animation
Typical applications of computer generated
animation are
1.
2.
3.
4.
Entertainment
Advertising
Scientific and engineering studies
Training and education
Principles of Animation
• Animation is possible because a biological
phenomenon known as persistence of vision
and a psychological phenomenon called as phi.
• An object seen by human eye remains
chemically mapped on the eye’s retina for a brief
time after viewing.
• This makes it possible for a series of images that
are changed very rapidly to blend together into
illusion of movement.
Types of Animation
• The two main categories are:
1. Computer- Assisted Animation
2. Computer generated Animation
Computer Assisted Animation: refers to 2D
and 2 ½ D systems that computerize the
traditional animation process. Interpolation
between key shapes is the only use of
computer in this type of animation.
• Computer Generated Animation: is
basically concerned with motion control of
the objects. The motion specification for
computer generated animation is divided
into two categories:
• Low Level Techniques
• High Level Techniques
• Low Level Techniques: these techniques
aid the animator in precisely specifying
motion. While using low level techniques
the animator usually has a fairly specific
idea of the exact motion that he or she
want.
• High Level Techniques: these techniques
are algorithms or models used to generate
a motion using a set of rules or
constraints.
• The animator sets up the rules of the
model or chooses an appropriate
algorithm and selects initial values or
boundary values.
Animation Tools
• There are two categories of animation tools
1. Hardware Tools
2. Software Tools
Hardware Tools: Hardware comes in many
shapes, size and capabilities. Some
hardware's are specialized to do only certain
tasks. Other kind of hardware do a variety of
things.
Most commonly used hardware in
animation
•
•
•
•
SGI
PC’S
MACINTOSH
AMIGA
SGI (SILICON GRAPHICS)
• SGI platforms are one of the most widely used hardware platform in
professional or broadcast quality computer animation production.
They have following features
• Extremely fast
• Produce excellent results
• Operate using the wide spread UNIX Operating System
SGI’s are produced by silicon graphic. They come in variety of types,
ranging from general purpose INDY to the high power “Indigo 2
Extreme” used to produce the animation.
Almost all major production studios use SGI’s state of he art software
like Wavefront, Alias.
PC’s (Personal Computer)
•
PC’s are very versatile machines. They
are favorite of various users because of
the following features it has:
1. Combination of flexibility and power
2. Less expensive
3. Provide good quality for their price.
Applications such as 3D studio and
animator studio are used on PC’S to
make animations.
Macintosh
• Mac’s were originally designed to be graphic and
desktop publishing machines. Mac’s did not
become widely known. Many people consider
Mac’s slow and inefficient but that is not true.
Mac is pretty useful for small scale companies
wishing to do nice looking applications.
• Many software companies are using Mac for
producing graphic application software like
Adobe with the products Photoshop, Premiere
and Strata with Strata Studio Pro.
Amiga
• Originally owned by Commodore. Amiga
computers have hold a position in the
computer animation industry for a number
of years. There are two software packages
that Amiga’s are basically known for: Video
Toaster and Light Wave 3D.
• Many Television shows use Amiga’s for
their special effects and animations.
Software Tools
•
1.
2.
3.
4.
The some of the most popular software's
packages used by the companies,
schools and individuals all round the
globe are :
3D Studio Max
5. Adobe Premiere
3D Studio
6. Alias/Wavefront
Light Wave 3D
7. Animator Studio
Adobe Photoshop
8. Elastic Reality
Design of Animation Sequence
•
In general an animation sequence is
designed with the following steps:
1.
2.
3.
4.
Storyboard layout
Object definitions
Key- frame specifications
Generation of in-between frames
• For frame -by –frame animation each
frame of the scene is separately generated
and stored. Later the frames can be
recorded on film or they can be
consecutively displayed in real time playback mode.
Storyboard Layout
• The storyboard layout Is an 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 sketched or it
could be a list of the basic ideas for the
motion.
Object Definition
• An object definition is given for each
participant in the action. Objects can be
defined in terms of basic shapes, such as
polygons or splines. In addition the
associated movements of each object are
specified along with the shape.
Key- Frame Specifications
• A key frame is a detailed drawing of the
scene at a certain time in the animation
sequence. Witching each key frame each
object is positioned according to the time
for that frame. Some key frames are
chosen at extreme positions in the action
others are spaced so that the time interval
between key frames is not too great.
Generation of in-between frames
• In-between frames are the intermediate
frames between the ky frames. The
number of in-between needed is
determined by the media to be used to
display the animation.
• If the motion is not too complicated, we
could space the key frames a little farther
apart.
Raster Animations
• We can generate real-time animation in
limited applications using raster
operations. Sequence of raster operations
can be executed to produce real-time
animation of either two dimensional or
three dimensional objects as long as we
restrict the animation to motions in the
projection plane.
Color Table Transformation
• We can also animate the objects along two
dimensional motion paths using the color table
transformations.
• Here we can predefine the object at successive
positions along the motion path and set the
successive blocks of pixel values to color table
entries. We set the pixels at the first position the
object on values and we set the pixels at the
other object positions to the background color.
The animation is achieved by changing the color
table values so that the object is on at
successively positions along the animation path.
Computer Animation Languages
• A general purpose languages such as C, Lisp,
Pascal or FORTRON is often used to program
the animation functions, but several specialized
animation languages have also been developed.
• Animation functions include a graphic editor, a
key frame generator ,an in-between frame
generator and other graphics routines.
• Scene description is a typical task in an
animation specification. This includes the
positioning of objects and light sources, defining
the photometric parameters (light source
intensities and surface illumination) and setting
the camera parameters (position, orientation,
and lens characteristics).
• Other standard functions of graphics are “Action
Specifications”. This includes the layout of
motion paths for the objects and camera. And
we need the routines like : viewing and
perspective transformations, geometric
transformations to generate object movements
as a functions of accelerations or kinematics
path specifications and visible surface
identification.
Key Frame Systems
• Key frame systems are specialized animation
languages designed simply to generate the inbetweens from the user specified key frames.
Usually each object in the scene is defined as a
set of rigid bodies connected at the joints and
with a limited number of degrees of freedom.
• E.g.. Single-arm Robot has six degrees of
freedom, which are arm sweep, shoulder swivel,
elbow extension, pitch, yaw and roll.
• Human body as over 200 degrees of freedom
Parameterized Systems
• Parameterized Systems allow object
motion characteristics to be specified as
part of the object definitions. The
adjustable parameters control such object
characteristics as degrees of freedom,
motion limitations and allowable shape
changes.
• E.g. Morphing in advertising.