Original subtitles

- Before we start animating our bouncing ball,

one of the most important thing you have to understand

is interpolation, timing and spacing.

Timing and spacing are two

of the 12 principles of animation.

Interpolation is quite new since it's the computer

that is doing the interpolation between two key frame

while in the past, they used to animate everything

by and adding drawings and drawings.

Timing is the pace.

It's the moment when the ball leave the ground,

is up in the sky and then hit back the ground.

It is defined by the key moment of the animation

or in the extreme,

the extreme high position and the extreme low position

in this case.

We have a timing of 12 frame to get to the highest position

and 12 frame to get back on the ground.

Spacing is the different of position of our sphere

from one frame to the other.

We can easily display the spacing

by going into the object option, motion path,

set the frame from zero to 24 and click calculate.

Then there we create a curve

that go through different point

that mark the position of the origin of our sphere

on each key frame.

The distance between those points is our spacing

and this spacing is based on the timing of our animation

and the interpolation between two key frames.

By default, blender interpolation is set to bezier.

What it does is that it creates an acceleration

when the object is moving from a key frame

and a deceleration when it's arriving on the next key frame.

These are known as easing out and easing in meaning that

you are easing out of the key frame leaving it

for an acceleration

and you are easing into the next key frame slowing down

before reaching or hitting its position.

So basically with that we've a very slow motion

and it accelerate along the way.

On frame 12, it will reach its maximum speed.

So the spacing will be the biggest.

And when it will come close to frame 24,

it will slow down.

This is what the bezier interpolation does by default.

You can change the interpolation mode

by selecting all the key frame with A

and pressing the T key.

It will open the interpolation panel

where we can choose which interpolation our key frame

will be using.

There are a lot of different pre-made interpolation

but we only need to focus on very first one.

To be perfectly honest,

I never used all the others,

but they can be very useful

if you want to build fast motion

for motion design, for example.

But in our case, we will be mostly working

using those three during the course.

Let's select the linear interpolation.

As soon as I will select it,

the behavior of the ball will change

and we will get a more robotic movement.

In the motion path tab,

I will click the update path

and now we can see that the spacing

between the different frames is always the same.

The spacing is even.

If we know compare and linear and bezier interpolation,

we can see that the timing is the same.

They reach the lowest and highest point at the same time

but on the bezier, we have a variation of the spacing.

So we have a variation of the speed of the ball

while in linear it's constant.

The linear interpolation is very useful for robotic moves

or for wall cycles for example

when the foot is on the ground.

Back to our motion,

I will select all the key,

press the T shortcut and set it to constant.

I will update the path and now we can see that

the ball is changing position only

when it reaches the next key frame.

So it's considered a constant interpolation

or no interpolation

and it's perfect to focus on the timing of your animation.

This is the kind of interpolation we use

when we are blocking the animation.

In most animation, blocking is the first stage

and it's very important.

And we will start blocking our bouncing ball animation

in the next video.

Stepped interpolation can also be very useful

whenever you want to give the stop motion style

to your animation like on this example.

To summarize, we have seen that interpolation occur

between two key frames,

that we can change the interpolation mode

using the T key,

that the bezier interpolation

allow acceleration and deceleration

or easing in an easing out,

that the linear interpolation has a constant speed

while the constant interpolation

doesn't show any interpolation

and is good to check out your timing.