Original subtitles

- [Instructor] Before we start animating the squirrel,

we need to talk about overlapping,

follow through and overshoot.

We talk about overlapping motion

when a part of a moving object

is delayed compared to the rest of the object.

So when we have a look at the current animation,

we can see that the ball is leading the motion

while the tail is trained to follow.

If we track the tip of the tail,

we can see that its position is offset

compared to the position of the ball.

This is something we will use a lot for tails, clothes,

whatever is hanging on our character,

but it can be used on any part of the body,

a relaxed arm on a walk cycle

or even on this crab character,

the eyes and the crab claws are currently following

the body motion with a slight delay

so it's also an overlapping motion.

We can also say that those parts are dragging

behind the body motion.

A very important thing is those overlapping motion

will communicate weight and stiffness of the material

or the character you are animating.

The more overlapping motion you will have,

the heavier it will feel.

The more overlapping motion you have,

the smoother it will feel also.

So it can also communicate

if your character is relaxed or stressed.

Follow through is a bit like overlapping motion.

It defines the fact that some parts of our character

are still moving after the character stops,

so their motion is offset compared to the character.

So basically an overlapping motion

generates a follow through.

And as explained before, it will communicate

the weight and stiffness of your character.

We generally use overshoot when a motion

has a dramatical change in its orientation

or when it's stopping.

It's accelerating until it reaches its destination

and we can see that it's going a little beyond

its final position and get back.

And this is what we call an overshoot.

Curve wise, it's pretty easy to identify

in the graph editor.

We have those two key frames that have the same value

so they are aligned on the y-axis

and we have an additional key frame

that goes a little beyond this threshold

and create the overshoot motion.

This is something we are going to use a lot

because it convey weight, but also speed, impact, balance,

a lot of things.

It can be very interesting for a punch, for example,

or to give extra appeal to a fast motion.

And when you combine overshoot with overlapping motion

or follow through, you can get very interesting animations.

In this case, there is an overshoot on the first punch

and some overlapping motion as the claws jiggle.

Here, I just want to show you a quick example

on how you can build

convincing overlapping motion very fast.

When opening the blender file,

you will be directly on the action to do this exercise.

With the first bone of the tail selected,

I will try to spot the frame

where the ball is currently moving the fastest

and it's frame 10.

I will select the x rotation curve of the tail,

duplicate the frame and switch them to auto cleanse

so that it's clean,

and move the key value up

so that the tail is dragging back.

Since the animation is looping on 40 frame,

there are great chance that on frame 30

I get the fastest motion of the ball the other way.

So I will duplicate my current frame

and move it on the negative side

so that the tail is dragging the other way.

Then as we are walking on a cycle,

the first and the last key frame must be the same,

so I would press shift D it to duplicate

and to make a proper blending,

I need to rotate to those two key frame

using individual origin

to align the starting and ending point

with the current shape of the curve.

Now to make it a little more stylish and interesting,

I will select those two extreme and scale them up a bit.

Since the overlapping motion is an offset

of the current motion,

I can select all the point of the curve

and press control C to copy them.

Then I will select the next tailbone in the hierarchy,

make sure I only have the x rotation curve selected

and I will press control V to paste the curve.

Then to slightly offset the motion,

I will press shift D to duplicate the whole curve

and move it before the frame zero.

This way I have twice exactly the same motion.

And if I now move the whole curve

by one or two frames to the right so I'm delaying it,

I will get a dragging motion for free.

From there, I can copy this curve,

select the next joint or the next bone in the tail hierarchy

and repeat the process.

Select the X curve, press control V to paste the curve,

I will align it with its original shape

and then offset it a bit by three frames.

So the idea is to use the same curve for each joint

but offset it in time by one or two additional frames.

Then you can play with the shape of the tail

by changing the shape of the curve.

Since I have a symmetrical motion

I can use the 2d cursor as a pivot point.

Its position is represented by the crossing blue lines

and as seen in the previous chapter,

you can place it wherever you want by shift right clicking,

or going into the view option and set its value, here zero.

Now I can press S and Y with all my key frames selected

to increase the amplitude of the curve

because I'm scaling the curve only on the Y axis

so we will have a broader motion of the tail

making it look more relaxed or heavier.

This is a fast, easy and cheap way

to get this kind of overlapping motion done.

It will sure be a little more complex on full characters

but that's a good tip.