Bouncing Ball Tutorial

This is a simple exercise to show you how you can create more "believable" motion. A key to effective animation is to imply that there is some "real world" physics at work. Anim8or imposes SOME simulation of physics, but others, you have to customize yourself.

In this exercise, we just want it to appear that a rubber ball falls to the floor and bounces a few times. Start with a brand new ANIM8OR file and name it "Bouncing Ball". Then go to OBJECT mode to build your "actor"
Anim8or-Ball01.png
1. Create your Actor
Create a primitive ball at the center of your 3D Universe - the size can be 70 units
Anim8or-Ball02.png
2. Set the Scene
Build the ball into a new scene at the center of the stage.
Hit the QUAD VIEW by tapping the DELETE KEY (or period key) on the NUMERIC KEYBOARD

Set TOP, FRONT and LEFT views with 8 5 and 4
Set the CAMERA view in the bottom right (1)

Set up these other conditions
  • The ball should start 200 units off the "ground"
    (Double click the ball and set it's y-value to 200)
  • The scene should run at 30 frames per second
    (VIEW - PREFERENCES - 30 FPS & Limit Playback)
  • The scene should be 10 seconds long
    (SETTINGS - SCENE - LENGTH=300 frames)

Once it's placed, you can start the animation process:

  • Turn on the KEYFRAME GENERATOR (the Green Key)
      • Open up the TIMELINE so you can see the eobject
        (Click the little "plus signs")
  • Be sure you're at frame 00
  • Use the MOVE tool to "touch" the ball and set a keyframe at 00 in the current position
Anim8or-Ball03.png
3. Let it Fall
  • Click on frame 30 and "touch" the object to lock it into the same location for the first second
  • At 2 seconds (Click on frame 60) move the ball to the ground level. You may want to turn off the X and Z axes so the ball can only fall straight down, and double click the ball to set it's Y location to exactly 35 (half it's height = ground level)

Bouncing Back
The "physics" of a bouncing ball is that in about as much time as it took to fall, it will return ALMOST to the same height. * Go to frame 85 and set the height of the ball to 180
  • Frame 110 should go back to 35
  • Frame 130 should go to 160
  • Frame 150 = 35
  • Frame 168 = 130
  • Frame 186 = 35

Now try copying (ctrl-c) the frame in 186... you can actually paste that keyframe to return the ball to the "ground level"

  • Frame 200 = 100
  • Frame 215 paste the "ground keyframe" (ctrl-v)
  • Frame 228 = 80
  • Frame 241 paste the "ground keyframe"

You can stop here - hopefully you get the idea, and you can come back to add more keyframes to continue the motion - but NOW it's time to refine the motion to make it more believeable:
Anim8or-Ball04.png
4. Refining the keyframes
If you go back and play the animation, you may notice the movement looks more like the pistons of an engine, than the bouncing of a rubber ball. This is because Anim8or imposes a bit of "momentum" on movement - "wind up" before a motion, and "follow through" after. We need to correct this to simulate the ball hitting a hard surface.

Use OPTIONS - GRAPH EDITOR to turn on the graph editor interface
  • Click on the "position.Y" label on the left hand side so you highlight the "path" of the y values
  • Double click the point at 01 seconds - turn it into a "Corner" point
  • Adjust the LEFT tangent handle so that it "flattens" out the START of the event - this way you won't have a "wind up" before the ball starts to fall. The RIGHT handle should be horizontal to impose a bit of "acceleration" as the ball starts to fall
Anim8or-Ball05.png
5. Fix the first "Bounce"
At 02 seconds, we DON'T want the ball to slow down before it hits the ground.
  • Double click the point at 20 it and turn it into a "Corner"
  • Adjust the handles so they point along the curves that they came from

You should see the "shape" of curve look more like what you'd expect to see in a bouncing ball.

The "PEAK" values at the top of the bounces are probably fine, creating believable deceleration as the ball travels up to the crest, and acceleration as it begins to fall back down again.

Refine the BOTTOM points along the ball's path (ie at 3.5 and 5 seconds etc.) and see if you can make the animation behave believably!

6. Complete the Animation
After you've gotten the idea, see if you can COMPLETE the "bouncing ball" until it "decays" to a resting state within the 10 second animation time.
  • Try Copying and pasting keyframes to see if you can animate more quickly that way
  • Try estimating where keyframes should go to create believable motion
  • Try cutting and moving keyframes if need be to refine timing of the bounces

IF time permits
  • Adjust the camera and add subtle camera motion
  • Render the final product ALIASED first, then ANTIALIASED
  • Dress up the set!
  • Add a "texture map" to the sphere
  • Hand your final piece in to the appropriate folder for show and tell!

Good Luck!

EVALUATION

Level
Level 4: Exemplary
Level 3: Competent
Level 2: Fair
Level 1: Poor
Animation Timing and Path Curves
The animation is precisely the right length, and the intervals between bounces appears particularly realistic; The Graph Editor has been effectively employed to create a believable "bounce"; Rendering is accurate to the specifications.
The animation appears complete and generally accurate.
The animation shows some control over the timing and paths, but appears incomplete
The animation shows little or no control over the timing and paths
Enhancements
Skills from earlier units (such as Materials, Environment Settings, Lighting and Camerawork) have been used exceptionally well to create an outstanding product
Skills from earlier units have been used appropriately to create an enhanced product
The animation is particularly simple without much enhancement
The animation indicates that earlier skills are lacking