Bouncing Ball

According to Scott Owen timing, or the speed of an action, is an important principle because it gives meaning to movement. The speed of an action defines how well the idea will be read to the audience.

Therefore when looking at the difference in timing when it comes to the weight of a bouncing ball, there are certain written principles that state that heavier objects take greater force and a longer time to accelerate and decelerate. For example, if a character picks up a heavy object, e.g., a bowling ball, they should do it much slower than picking up a light object such as a basketball. Similarly, timing affects the perception of the object size. A larger object moves more slowly than a smaller object and has greater inertia. These effects are done not by changing the poses, but by varying the spaces or time (number of frames) between poses. (Owen, 1999)

In How Things Work, Louis Bloomfield explains the physics of the bouncing ball, "When a ball bounces from a rigid surface, the ball's surface distorts inward and then pops back outward. During the inward motion, the ball stores energy--pushing its surface inward takes energy. During the outward motion, the ball releases that stored energy. But not all the energy invested in the ball emerges as useful work. Some of that energy is turned into thermal energy and never reappears. A properly inflated basketball returns a good fraction of the energy it receives while other balls may not. In fact, a bowling ball bounces pretty well from a hard surface such as cement. But when it hits a softer surface such as wood, the wood receives much of its energy and wastes that energy as thermal energy."

Squash and stretch is an animation technique that illustrates the effect of gravity and force on the volume and shape, creating a believable and interesting animation, which is achieved through maintaining a consistent even volume though the shape changes. This principle when applied in real life is observed in the flexing of the muscles, or when watching a rubber ball bounce. The arm in the muscle swells when the bicep is contracted and the ball flattens and widens as it hits the ground. (Skidgel p)














In conclusion the ball I chose to animate is a baseball. The weight of the ball is slightly heavy, yet the size of the ball is small resulting in it produces less bounces.

References:

http://www.siggraph.org/education/materials/HyperGraph/animation/character_animation/principles/timing.htm
G. Scott Owen, Timing and Motion, 1999

http://howthingswork.virginia.edu/bouncing_balls.html
Louis A. Bloomfield, How Things Work, 2008

John Skidgel, Design Menus With Encore Dvd.

http://www.mattornstein.com/images/downloads/ball_logo.jpg