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.Entertainment 2.Advertising 3.Scientific and engineering studies 4.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 The some of the most popular software's packages used by the companies, schools and individuals all round the globe are : 1.3D Studio Max5. Adobe Premiere 2.3D Studio6. Alias/Wavefront 3.Light Wave 3D7. Animator Studio 4.Adobe Photoshop8. Elastic Reality

In general an animation sequence is designed with the following steps: 1.Storyboard layout 2.Object definitions 3.Key- frame specifications 4.Generation of in-between frames Design of Animation Sequence

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 play- back 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 in- betweens 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.