Original subtitles

- [Instructor] We have left last video

with our happy bouncing ball, bouncing and bouncing.

But now, I'd like it to move forward a bit.

So let's do that together.

The first thing I will do is to press

three on my num pad to switch to side view.

Now, instead of making my animation loop over 24 frame,

I'd like to make the animation a little bit longer.

So I will re-open my timeline,

and I'd like to repeat the animation four time.

So I can tie in all time 24 frames

to get to the right frame number.

But the problem is that my bouncing ball animation

is not repeating over those 96 frames.

So the more logical method to make it repeat

will be to select all my keyframe,

duplicate them by pressing Shift + D,

X to move them on the x-axis,

and type in 24 so that they will be moved

by 24 frame on the x-axis.

Then, I can press Shift + R to repeat the operation.

The problem with this method is that if we have

any modification to be added to the animation,

we will have to reduplicate everything

or modify it on each bounce.

While it's not super painful on such a simple animation

duplicating only four time,

this is not an efficient way to do it.

So I will reset what I've done

and with all my keys and curves selected,

I will press Shift + E to open

the keyframe extrapolation menu.

By default our keyframe extrapolation is set to constant.

It means that whenever I reach

the very last keyframe in my animation,

the value won't be changing anymore.

That's why we get flat curve.

But judging by this extrapolation menu,

we can see that we can switch it

to linear extrapolation or even make a cycle.

You can also access the extrapolation operation

through channel panel in the header of the graph editor.

With all the curves selected,

let's choose make cyclic.

Boom, our animation is now

cycling infinitely on the timeline.

And the cool thing about using extrapolation

is that modifying our animation will be repeating

and updating the along the whole timeline.

(graphic swooshes)

With this problem fixed,

I'd like my ball to move forward in space.

So I'd like to animate the y-axis of the ball.

So I will insert a single keyframe on the y-axis,

go to frame 24, move the ball by about nine meters,

go back onto the transform channel,

right-click and insert a single keyframe.

If I now play the animation,

the ball will move forward

only on the keyframe we have inserted,

and since Blender is creating by default

a new keyframe with the bezier mode,

we have an acceleration and a deceleration

of the ball so it doesn't look super unnatural.

While this kind of locomotion

could be a little more complex,

we will consider that our ball

is moving at a constant speed.

So I will select both handle,

press the V key and switch them to vector.

You could have chosen to press the T key

and switch to linear interpolation,

but I prefer to use vector interpolation

to keep the handles available.

When I watch this motion,

I feel like the ball should move a little further.

So I can take my last control point

and move it a bit up more

or insert a new value in the transform channel

and don't forget to insert the keyframe.

Or we can directly change the value of the keyframe

by going into the F-Curve properties

and enter 10 meters in the value of the keyframe.

This is a good method when you want

to enter very precise values.

Now, I'd like my ball to continue moving on on each bounce.

So I could duplicate the last keyframe, offset it

or insert a new a keyframe and set it to 20 meter.

But again, if we want to modify the timing of our animation

making the jump a bit a longer,

I will have to modify those, too.

And on a more complex animation,

that would be very painful.

So let's get rid of this and find another solution.

If we go back to the extrapolation menu,

we will find an option that allow us

to create a linear extrapolation.

Blender will take the last two keyframe of an animation,

and it will do an extrapolation

based on the value differences between those two.

So that's a great step forward in our animation,

but there is something that bother me.

When our ball hit the ground,

it stays on the ground for a few frame.

The problem is that it's sliding currently,

and it doesn't look good.

I'd like the ball to stay

where it is when it's on the ground

and move forward whenever it's airborne.

To fix it, I can simply duplicate the very first frame

and move it on frame three,

but I need this new motion

to repeat along the full animation.

So I will press Shift + E and choose constant extrapolation

to get rid of the linear extrapolation.

But now, my animation is no longer repeating,

and whenever I'm re-adding a linear extrapolation,

it will just continue on moving instead of stopping

whenever the ball is contacting the ground.

So I can try using a cyclic extrapolation,

but the problem is that the ball will get back

to its original position after each cycle.

So I'd like it to cycle but with an offset.

And what we can do is select one of the key

of the curve an go to the modifier tabs here.

And we can add a cycles modifier.

So it works exactly as if we were

adding the cyclic extrapolation,

but we do now have option on the cycle behavior.

I can change the way it act before and after the cycle.

So if I go onto the after,

I can ask Blender to use the repeat with offset.

And what it does is that it takes the very last keyframe

and use it as a new starting point.

So offsetting the animation is currently adding it

on top of the latest keyframe.

(graphic swooshes) An extra motion

is missing, though.

If we watch this video,

you'll find the link in the resources PDF,

I'd like you to focus on the body shape

and orientation of this lynx.

During this gorgeous motion,

we can see the squashing and stretching,

but we can also see some rotation of the body.

The body in the beginning is oriented toward the up point

and then oriented toward the landing point.

So we do need to input those information

on our bouncing ball.

To get a better preview of the motion of the ball,

(graphic swooshes)

I will calculate the motion path.

As seen in the previous video,

I will go into the object option,

motion path and click calculate the path.

I will change the path type to in range

and change the end frame to 96.

This will give us the motion path of our ball,

and it's going to be easier for us

to figure out how much we have to rotate it.

The idea is to simply rotate the ball

toward its next position or its next frame position.

And once we have past the highest point,

we will make the ball pointing toward the previous frame.

Since our first frame is exactly the same

(graphic swooshes)

as the latest frame, or frame 24,

I will jump to frame 24

and give the correct orientation to the ball.

It seems that 11 degrees looks fine.

Then, I will right-click and insert a single keyframe.

A new channel has appeared in the graph editor.

It's our X ruler rotation.

So I will now go back to the frame

where the ball is currently leaving the ground

and rotate it by minus 12.5 degree toward its next position.

So now as we have did before,

I will duplicate the last frame,

frame 24 of this ruler rotation,

and move it onto frame zero,

pressing Shift + D, X and moving it with the mouse.

Now that the initial frame zero

and final frame 24 are the same,

I can select my curve

and press Shift + E and make it cyclic,

and it already looks pretty cool.

So while the motion I'm seeing

right now is pretty satisfying,

you know that we need to check it frame-by-frame.

As any craft, a perfect animation doesn't exist,

and the level of quality you will reach

depend on the time you can spend on your animation.

In this case, I'd like to polish the animation a little more

by making frame number one pretty flat,

because I don't really like the fact

that the ball is slightly leaning backward

when it's getting in its flattest position.

In the graph editor

with the X ruler rotation curve selected,

I will press I to insert a new keyframe

and choose only selected.

This way, Blender won't add

any additional keyframes on the other curves

and our graph editor will remain clean.

Then, I can grab this key, move it on the y-axis,

holding Shift to get a more precise movement.

And I will call this first bouncing ball animation done.

The technique we have used in this video,

adding a rotation motion based on the location motion,

the up and down motion of the ball,

is called the layered approach.

It means that you add layers

and layers of motion during the polishing stage,

not during the blocking stage.

And we'll study this technique more in depth later on.

To summarize, we have seen that we

(graphic swooshes) can create cycles using

the Shift + E shortcut and choose different extrapolation.

We can access more advanced cycle option using modifiers.

We can use current motion of the ball as the guide

to add new motion to it in a layered approach.