Below I will try to show the theory of the assignment as well as the technical aspect for Maya

 
 

THEORY:
Extremes, Keyframes, Squash and Stretch, & Timing

 

-Timeline & other important terms-

Back in the 20's and 30's animators drew out their entire animation on sheet of paper. They would draw a line of action
that represented the movement of the character or object and draw several ticks along that line to represent the timing
of the object along that line of action. This sketching became the forerunner to the animation chart which became the
forerunner of the animation timeline we see on our computer screens in various programs. The line represented the
animation from start to end (of that particular action/animation), and the ticks represented the position of the animating
object in the animation at a given point in time.

Since it takes 24 pages of drawings to visually represent 1 second of animation it is impossible to draw ticks for
every page. So very often the ticks are based off of seconds but are at the animators discretion.
This means the ticks can be miliseconds, or minutes. The point is that the ticks represent where the drawing
(animating object) will be along the length of time, between the start and end.

Take for example if you had a sphere animating from left to right in 1 second. This is how an animator might draw
out his animation:

 

-Extremes, In-Betweens, Breakdowns & Tweening-

In the 1920's animators used to have to draw every single drawing in an animation. In order to speed up the process,
famous animator, Grim Natwick suggested to his employers that if they could give him another animator to just draw
the frames in-between the the important action defining frames that he could get twice as much done.
Thus the the in-betweener animator was developed. Eventually the process of developing the imagages in between each
important image went from being known as the in-betweens to tweens. The action of drawing them became known as
tweening. The important images are known as extremes and the reason why they are called so is because they define
a change in dirrection, an end of the current action. The mid point between two extremes is known as the breakdown
because it is the passing point. Also known as the passing position.


-Keyframes-

These are drawings or frames of the animation that are so important they define the entire animation. If you were to
just look at a string of keyframes you would be able to understand absolutley everything about the animation from the
the movement to the emotion. A key is a storytelling drawing that shows what is happening in the shot. Very often
extremes will be keys. Keys are meant to "read what occurs" in an animation. Since you will be working with frames
on your computer, instead of pieces of paper, you will be keying them for your animation. Hense the term keyframe.


-Timing-

It is how fast or slow an object moves from point A to B. Not everything moves at an even pace. Some things are slow to
begin movement, others are slow to end. Sometimes an object flung into the air slows and hangs for a bit before coming
crashing to the earth. There are many factors of force, velocity, and gravity that effect the time it takes for an object
to traverse. Animators used to draw their line of action and indicate with ticks where the position of the object would be
during that moment, during that time between A and B, during start and end.


-Squash & Stretch-

Everything has a bit of squash and stretch. Squash and stretch is deforming the animating object in order to express the
action or movement. Often you will see in cartoons a character walk off a cliff and his lower body falls and stretches
pulling his head with him. Usually the character will hit the ground and bounce as if made of rubber. This is called
squash and stretch. Not every object has the consistency of a rubber ball so use it when appropriate. If you take a
bouncing rubber ball and slowed it down so you could see how it deforms it might look a little like the diagram below.
Animators push the squash and stretch theory to the extreme to add excitment and make the animation interesting.
Falling from the sky or being shot up into it an object will tend to stretch due to gravity. Once collision with another
object occurs it will often squash into itself. It is important to note that the mass of the object does not change. Imagine
a balloon filled with water. If you squeez it, it will deform, however it does not get bigger or smaller. The water is just
shifted into a different formation. The amount of mass remains the same though the shape changes drastically. Take
a look at the bouncing ball diagram below to understand squash and stretch better.


 

TECHNICAL:
Extremes, Keyframes, Squash and Stretch, & Timing
 

 

1. SETUP: Create a sphere and align it so it's pivot point is onthe 0,0 axis point on the grid plane. Align the very bottom of the sphere so that it is "kiss touching" the grid plane.

 


1.1a. Create a sphere by clicking CREATE - POLYGON PRIMITIVES - SPHERE

OR

1.1b. Click the Polygons Tab, Click the Sphere Icon

1.2. Click with left mouse button and drag to create sphere in scene.
Click on it to make sure it is selected (Should be highlighted) and then click on the Move Tool:

OR Shortcut Key 'W'. Use the move tool to align the sphere properly.

 

 

2. KEYFRAMING EXTREMES: Key your extremes. Adjust any auto features the 3D package may be employing.

 

2.1. Click on frame 1 in the time line, make sure your object is selected, and manually set a key on the first frame.
Click on the Animation tab and then click on the Set Key Icon.

OR press the shortcut key 'S'

2. Click on the last frame 24 and set a key there as well.

2.2. Click on frame 12 and then click the autokey icon. You can use set key here but I'd like to introduce autokey.
In a lot of ways it can make your life easier.
Autokey will automatically make a key frame for you on the frame you have selected when you manipulate the object
(Depends on settings why get's Keyed)


2.3. Make sure you are on frame 12 and move the sphere up on the Y axis.
You will notice that a key is automatically made for you.
Your scene should have 3 keyframes (extremes) now. It should look something like the image below.
Notice the red lines indicating keyed frames.


Playing or rendering your scene will produce a result that looks like this:

 
Click here if the video doesn't auto load.

The ball bounces but does not look realistic. This is the point where we need to go in and add some squash and stretch.

2.4. Open up your Graph Editor by clicking on WINDOWS - ANIMATION EDITORS - GRAPH EDITOR



You will see something that looks like this:

Notice the lines conecting the points.
They are curved. This means maya is trying to smoth out the movement of the sphere as it moves through the keys.
It is trying to ease in and ease out or coushin how the sphere reaches its key and moves on.
Maya does a pretty good job of trying to inerpolate
and simplify our lives but we want to do this exercise manually to fully understand the theory behind it.
We want to tweak this animation to our exact liking.

2.5.Click and drag selecting all the points and lines. Once selected click on the Linear Tangents Icon.

Your Graph Editor should look something like this now:

Notice how the lines conecting the points are no longer curved. They are straight and rigid.
Playing or rendering your scene will produce a result that looks like this:

 
Click here if the video doesn't auto load.


 

3. SQUASH AND STRETCH: Create squash and stretch keyframes whenever your sphere changes direction, momentum, hits a surface, etc. Make it look like it is interacting with the environment. Make it adhere to the laws of gravity, etc.

 

3.1. Set a key 2-4 frames before before and after your extremes. You can manually do this or autokey.

Using the scale tool make the sphere look "squashed" on the key after the first frame.
Make sure to adjust the placemnt of the object so that it is still "kiss touching" the "ground"

If you have autokey on than it will key it for you, if not make sure you manually set the key.
Make sure your scale tool is set to object mode.
If not you will get an error like this one in the bottome right dialogue box:

// Warning: Non object-space scale baked onto components.

To have a better understanding of what this problem is please view this video.

Double click the scale tool icon to open up its options box. Make sure object is selected.

3.2 On the key before the sphere reaches its apex (maximum height from the bounce) use
the scale tool to make the sphere "stretch".
Make sure you move the sphere down on the Y axis a bit so that the stretched sphere
isnt higher or at the same height of the apex sphere.

3.3 Do the same for the key after the apex. Or you can right click on the key before the apex and copy it,
Then right click on the key after the apex and paste it.

3.4 Go into the Graph Editor, select all the points and lines and click on linear Tangent once again.
Your animation should look something like this:

 
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Here is a slower look at what is going on:

 
Click here if the video doesn't auto load.

 

 

 

4. TIMING: Play around with your keys adjusting them. Move them forward or backward to get the timing of the action to look natural. Make additional keys where needed to prolong areas like the apex of the bounce. Remember to always have movement. Nothing ever remains flat and rigid when in motion.

 

4.1 Prolong the time the sphere spends suspended at the apex of the bounce by copying the key
that is at the appex and pasting it beside it.
Adjust the two apex frames BY shifting them apart from each other.

If you SHIFT + CLICK a frame it will highlight in red. You can then drag the key to your desired frame.

If you want to select more than one frame and move them all at once or want to scale the distance between them you can
SHIFT + CLICK and drag your your cursor along the timeline.

On ether end of the red selection are arrows.
If you click and drag one of these arrows it will scale the time between each key starting from the furthest key.
The closest key drags out while the furthest key is anchored.

There are also two opposite facing arrows in the center of the red selection.
Clicking and draging on one of these arrows allows you to move the entire selection.
This option will not scale the time between keys. It will remain the same.

4.2 Create a key in between the apex(s). Nudge it up on the Y axis ever so slightly.
This will add a little realism to the sphere losing momentum and being overtaken by gravity.
Adjust it in the time line to be closer to apex key on the right.

4.3 Adjust each key frame as necessary.
Usually you will have to add some frames when the sphere is on the ground squashes and launches upward.
And usually you will have to reduce frames for when the sphere falls to the ground and squashes.

Check out the screen shot of the placement of keys, adjusted for timing.

Below is the result: A smooth reactive interesting bounce:

Linear Tangents

 
Click here if the video doesn't auto load.
PROJECT

 

Make a sphere bounce across the screen at least 3 times. Use squash, stretch, and timing.
Make sure to have a diminishing effect as the sphere moves across the screen.
Remember to set your keys using linear tangents and then once completed render out an AVI or MOV.
Make the image 320 x 240.
The point of these exercises is that you should be able to have the skill to
make genuine animation without the help of the computer (Autosmooth Tangents).
You should understand your squash, stretch, and timing.
The computer helps you achieve better animations but you yourself must create great animations
using time tested theories and practices. See the example below.

Linear Tangents

 
Click here if the video doesn't auto load.

Autosmooth Tangents