CHAPTER 7

ANIMATION

Animation possible due to biological phenomenon called persistence of vision and psychological phenomenon known as phi.

Object seen by human eye remains mapped on retina for the brief time after viewing and combined with mind need to conceptually complete the action.

This make possible after images changed very slightly and very rapidly, one after other to seemingly blend together into a visual movement.

Television and projector build frame or picture every second, the speed with which each frame is replaced by the next one makes the images appear to blend smoothly into movement.

Quickly changed the viewed image is the principle of an animatic, flip-book, or a zeotrope.

Change the shape and move or translate a few pixels for each frame to make object travel across the screen.

2-D
1. Visual change only on the flat Cartesian x and y.
2. A blinking word, color cycling logo, cel animation, button or tab that change state on mouse rollover to let user know it is active.
3. Path animations increase the complexity of an animation and provide motion, changing the location image along the predetermined path during the specified amount of time.
4. Ex. Flash and PowerPoint.

21/2-D
1. An illusion of depth (z axis) is added to an image through shadowing and highlighting, but the image still rest on the flats x and y axes in two dimension.
2. Embossing, shadowing, beveling, and highlighting provide a sense of depth by raising an image or cutting it into a background.

3-D
1. Creates a virtual realm in three dimensions, and changes (motion) are calculated along all three axes (x,y and z).
2. Allowing an image is created with a front, back, sides, top, and bottom to move towards.
3. Allowing viewer to wander around and get look at all object part of angles.

Cel animation artwork begin with keyframes which the first and last frame of action.

The series of frames in between keyframes called tweening. Tweening is an action that requires calculating the numbers of frame between keyframes and the path the action takes.

The action is checked by flipping through the frames and pencil frames are assembled and then actually filmed as a pencil test to check the smoothness, continuity and timing.

Kinematics
1. Study of movement and motion of the structures that have joints, such as a walking man.
2. Walking animation step is tricky, need to calculate the position, rotation, velocity and acceleration of all the joints and articulated parts involved knees, hips flex, shoulder and head.
3. Example software such as e-frontier’s Poser.
4. Inverse kinematics is the process by link object such as hand to arms and defines their relations and limit. It available in high 3-D programs like Lightwave and Maya.
Morphing
1. Is a popular effect in which one image transforms into another.
2. Transition not only between still images but also often between moving images.
3. Software like Black Belt’s Easy Morph and WinImages.

Rolling Ball
1. Create a new blank image and fill it with a sphere.
2. Create a new layer and place some white text on this layer at the center of the image.
3. To animate by rolling it across the screen, first need to make a number of rotated image. Rotate image by 45-degree increment to create a total of 8 images, rotating a full circle of 360 degrees.

Bouncing Ball
1. Need to flash a ball on the computer screen rapidly and in a different place each time to make it bounce up and down.
2. Gravity make bouncing ball accelerate on its downward course and decelerate on its upward course.
3. Simply figure that ball will uniformly accelerate and decelerate up and down the pixels of screen by the squares: 1,4,9,16,25,36, 49, 64, 81, 100.
4. For perpetual-motion bouncing ball, it goes up the same way it comes down because the up and down motion are symmetrical.