Bouncing Ball Tutorial:

Intro: short and sweet... I know what you're thinking... a boring bouncing ball.

But Even Dory can be abstracted to a ball...uh, sort of... ok it's a stretch but seriously:

This basic exercise will teach you the fundamentals of animation principles:

• Workflow
  Learn to move around Maya like a pro animator.... one day!

• Arcs
  A dropped ball will fall in arcs rather than straight lines. In fact, most things in nature move in arcs. We like arcs because they make for nice fluid motion.

• Timing/Spacing
  A ball moves slower at the top of it's bounce arc and fastest right before it hits the ground (acceleration due to gravity).

• Squash and Stretch
  The ball begins to stretch out as it falls to the ground to show exaggeration and to imitate motion blur. Upon impact, it squashes to exaggerate the force of impact. Too much squash and stretch can make something look very “mushy”. Make sure the overall volume is relatively the same. A good rule of thumb is that you “feel” squash and stretch... you don't see it.

• Patience and Practice
  Good animation takes A LOT of practice and patience... yes, even a simple bouncing ball!

Setting up your workspace:

First go into your preferences by clicking on the little button near the bottom right hand corner of the screen:

Setup your preferences as follows:

In Settings, set the frame rate to 30 fps, then in the subsection “animation” enable weighted tangents and change the default out tangents to “stepped”

To enable playback in real time, go under the Timeline subsection and change the playback speed to realtime.

1. Open up the file and you should see a ball rig with a ground plane. Go to your side view.

2. Position the initial position of the ball (the top of the arc on the first drop).

3. 
   
   Key (select a control(s), then press s) the main positions of your ball bounce in stepped mode (stepped out tangents) according to your REFERENCE. Make sure you're keying all the controls in your main positions/poses. After you're happy with all your ball poses go head and playblast (window->playblast) that sucker. This creates a video file of your animation that simply takes screenshots of every frame in your currently active camera view. It gives you an very accurate preview of what your animation looks like without the pain of rendering all the frames. PAY ATTENTION to the timing, it should look like a ball falling even if the keys are stepped. Some key points to keep in mind:
   
   - The ball begins to stretch as it increases velocity and squashes as soon as it hits the ground.
   - The ball travels slower at near the top of its arc and faster near the bottom.
   
   

4. No one gets timing down on the first try, select ALL the controls and move keys around accordingly to fix timing issues either in the dope sheet (window->animation editors-> dope sheet) or the time slider (hold shift + click the frame you want to move, then hold middle click and drag) You should have something that looks like this:

5. 
   

   After a number of playblasts and you're happy with the way your playblast looks, you can start splining! Select all your controls, open the graph editor (window->animation editors-> graph editor) and click the frame all button. The graph editor is a basically a plot of position(y-axis vs. time (x-axis) so you can see you're key layouts visually. Even if you hate math and graphs, you will loveee the graph editor! ... We want some nice smooth looking curves... because smooth curves in general leads to smoother motion.
   
   With all the keys selected.. press the spline button! At this time, you need to change your default out tangents to clamped. As shown in the setting up your workspace part of this tutorial, go into your preferences and go under the animation subsection to change this.
   
   Now go back to your side viewport and playblast! Mmmm.... smoooooth motion!
   
   You should have something like this:
   
   But there are still a few kinks... the ball is going under ground? Bumpy/abrupt motion? The graph editor will put them to shame.

6. We're most concerned with the the translate Y component of the ball's main control since that's what controls the height of our bounce with respect to time. So select the Y component of our ball's main control and frame it all like so:

As you can see, the arc's are a bit bumpy, start moving keys and playing with tangents to get some smooth arcs. At the bottom of each arc (where 2 of them meet), you need to break the key's tangents to make a nice sharp bounce. You do this by selecting the key and pressing the break tangent button like shown above. Move the tangents by middle click and dragging to get something like:

7. Make sure you go back to your animation and check the results! The graph editor is only a tool! Only use it to tweak your animation, don't spend all your time making your curves super smooth... it's unnecessary. Keep your eye on the animation and see if it looks right. If not keep moving keys, adjusting your spacing/timing, and messing with your curves until you get something awesome!