Bouncing Ball

Animation: Bouncing Sponge Balls

How to animate 2 sponge balls which compress and

decompress on impact and make a sound while doing so Mr. Brunato

(Revised Nov 18, 2007)

  Original and printable version.

Step One: 

Animate the first sponge ball

• draw a ball

• use tweened animation to move it around the scene

• if it moves a short distance, use a small number of frames in between each keyframe

• if it moves a long distance, use a large number of frames in between each keyframe

• this keeps the ball moving at a consistent speed

Step Two:

 Animate the second ball

• after the first ball bounces 4 or 5 times, add another ball and animate it on its own layer

• make sure the ball is a different colour

• go to the menu and select Insert > New Layer

• animate the second ball using tweened animation, just like the first ball

• animate the sponge balls until they overlap in their respective paths

Step Three: 

The collision

• at some point the two sponge balls will overlap each other

• let’s say the overlap occurs on keyframe 70

• on layer one, right click on keyframe 70 and select Convert to keyframes

• on layer two, right click on keyframe 70 and select Convert to keyframes

Step Four

 - Change the direction

Please note that since the layers are acting independently of each other, you have to change the

direction of each ball after a collision.

• after the 2 sponge balls collide they should change direction

• put your finger on the screen where the ball should go

• click on the keyframe after the collision

• move the ball to where your finger is

• modify the timeline:

• if the ball moves a short distance, the number of frames in between the keyframes

should be small; if the ball moves a long distance after a collision, there should be

many frames inbetween each keyframe

• continue animating until the 2 sponge balls overlap again, keyframe the collision point as

in Step 3 and change the direction as in Step 4

• have the sponge balls collide 3 or 4 times

Step Five

 - Compress and decompress bounces and collisions

• There is a keyframe at every instance the ball bounces, either off each other or off the


• add a keyframe before and after each bounce

• let’s say the ball bounces at keyframe 20, add a keyframe at 19 and 21

• right click on frame 19 and select Convert to keyframes

• right click on frame 21 and select Convert to keyframes

• click on keyframe 20

• right click on the ball and select Free Transform

• squish the ball

• move it into position using the arrow keys on the keyboard

Step 6

 - Choosing a sound

• go to the menu and select Window > Common Libraries > Sounds

• a sound library will appear

• preview the sounds by clicking on the play button

• select a sound that you like

Step 7

 - Adding sound

• create a new layer

• double click where it says Layer, and rename the layer, Sound

• select a point when the ball collides or bounces off the side: let’s say keyframe 20

• on the Sound layer, right click keyframe 20 and select Convert to Keyframes

• click on the sound from the sound library and drag it onto the stage (the empty area where

you animate)

• do this for every bounce or collision

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