Computer
animation is the art of creating moving images via the use of computers.
It
can be described as an art form that involves bringing still images to life using
computer technology. Animation in this form can apply to images on a computer
or to those in film. When computer animation is used for movies, it is often called
computer-generated imagery (CGI). It
is a subfield of computer graphics and animation. Increasingly it is created by
means of 3D computer graphics, though 2D computer graphics are still widely used
for stylistic, low bandwidth, and faster real-time rendering needs. Sometimes
the target of the animation is the computer itself, but it sometimes the target
is another medium, such as film. It is also referred to as CGI (Computer-generated
imagery or computer-generated imaging), especially when used in films.
To
create the illusion of movement, an image is displayed on the computer screen
then quickly replaced by a new image that is similar to the previous image, but
shifted slightly. This technique is identical to how the illusion of movement
is achieved with television and motion pictures.
Computer
animation is essentially a digital successor to the art of stop motion animation
of 3D models and frame-by-frame animation of 2D illustrations. For 3D animations,
objects (models) are built on the computer monitor (modeled) and 3D figures are
rigged with a virtual skeleton. For
2D figure animations, separate objects (illustrations) and separate transparent
layers are used, with or without a virtual skeleton. Then the limbs, eyes, mouth,
clothes, etc. of the figure are moved by the animator on key frames. The differences
in appearance between key frames are automatically calculated by the computer
in a process known as tweening or morphing. Finally, the animation is rendered.
For
3D animations, all frames must be rendered after modeling is complete. For 2D
vector animations, the rendering process is the key frame illustration process,
while tweened frames are rendered as needed. For pre-recorded presentations, the
rendered frames are transferred to a different format or medium such as film or
digital video. The frames
may also be rendered in real time as they are presented to the end-user audience.
Low bandwidth animations transmitted via the internet (e.g. 2D Flash, X3D) often
use software on the end-users computer to render in real time as an alternative
to streaming or pre-loaded high bandwidth animations. Hope
that helps, 
Cody Landon
Software and Graphics Engineer
www.3DMagix.com | 
