Original subtitles

- [Instructor] Before we start animating our query character

we need to understand the difference

between world space and local space.

If we have a look at this world object,

as soon as I will change its value on the x-axis,

it will move on the x-axis.

If I change the Y the Z,

it will follow the global axis, also known as world axis.

So our sphere is currently moving following world space.

If I now rotate my planet on the X axis,

we can see that it's Y axis is no longer aligned

with our seen axis also known as world axis.

But if I change it's Y value,

it will still slide along the Y axis of our world space.

And this is because on any object,

transform channel are read in hierarchy.

The first transformed channel read are location,

then rotation, and finally scale.

That's why the rotation doesn't affect

the location transform of the planet.

It will be such a pain to animate or to read curve.

But since scaling is read or is performed after rotation,

we can see that when I scale on the Y, X or Z,

it does follow the local space of the planet.

To better illustrate what is local space

let's display the Bob collection.

This is Bob, and as you can see,

he's aligned with world space.

His head is pointing upward along the Z axis.

His origin point is slightly offset

from the center of our scene.

And we can see this in its location coordinates.

So what I will do now is to place Bob on our planet earth.

So we can see that Bob has no rotation

and is slightly offset from the Z axis.

I will now parent Bob to the planet.

So I will first select Bob,

then the planet and press control P objects.

Now, Bob is a parent of our planet object.

And as soon as our planet object move or rotate,

Bob will follow.

When rotating the planet on the Y axis,

we can see the coordinates in the rotation channel.

And if I display my planet axis,

we can see that they're aligned with Bob axis.

So Bob has been rotated in world space his Z axis

is no longer pointing up.

But if we have a look at his rotation coordinate,

we can see that they are still to zero.

Because while the word has been rotated,

Bob, hasn't rotated, he hasn't moved off an inch.

He has visually rotated in world space

but in its local space, he hasn't rotated.

It's like when you are driving a car,

you are moving in world space because the car is moving,

but you you're not moving, you're still sit in the car.

You are a child of the car.

So if I now edit the z location of Bob,

we can see that he's moving along its own Z axis,

also known as local space.

So world space correspond to the axis in our scene

while Bob local space correspond to the axis

that are displayed on top of his head.

So if we now have look to the graph editor,

whenever I will move the X curve of my planet, it will

follow the world space as our bouncing ball previously.

But if I now do the same with Bob,

I will see that will be offset on its own X location,

on its local space.

And this is a very important concept

when we will start animating characters.

Think of the hand parented to the arm,

we will need to animate it in its local space.

As the hand will be the child of the arm.

On top of this, we still have our channel sequence,

meaning that the rotation occur before the scale

and after the location.

So I can still rotate the character in its local space

and then scale it afterward.

And both rotation and scaling will follow its local axis.

So, basically you are always animating

in the local space of your character, object, whatever.

But by default it's local axes are aligned with world space.

But as soon as you have a parent and child relationship,

there are great changes that they're

no longer aligned with space.

If you are using the gizmo from your transformation,

you can switch it to local space.

And a lot of animators uses the gizmo to animate

and uses them with a local space.

As I've rotated the planet

and Bob is still a child of the planet,

it's local space has been rotated,

and we can see that the axis of the manipulator

or gizmo are aligned.

So when I use the manipulator to move Bob on its Z axis,

I can see his Z coordinate changing.

So the gizmo give us a great representation

of the local space of our character.

And it does also work well whenever I'm performing

a rotation around the nexus.

And we also have a rotation and scaling gizmo

at our disposal.

But you have to be cautious with those manipulator

because they can be misleading.

It's totally fine to use them to manipulate your character,

but don't rely on them too much when it comes to figure out

what is the local space of your character.

Because if I do rotate my character

and then try to perform a translation,

the manipulator will be visually aligned

with the local space of my character.

But the location coordinates of my character

wont be aligned anymore.

Because the rotation is performed after the translation.

So when I will be editing my curve, I will be editing

the current Y movement I see on the screen right now.

Because the curve's output has the value of the location,

rotation and scale that we can see in the transform channel.

And it's not the case of the manipulator.

So if I really want to align the manipulator

with the local space of my character,

I need to reset any rotation on my character.

And now they are aligned.

If my character is rotating,

moving it using the manipulator in local space,

will currently edit different location values.

I know it can be a bit confusing, but don't worry.

It will make sense whenever we are animating.

And you won't have to take all those things

in consideration, but it's important for you to learn them

to better understand animation in 3D space.

When editing your curve with a bit of trial and error,

their behavior will make sense,

even in local space, don't worry.

To summarize, we have seen that by default an object space

is world space.

In a parent to child relationship,

the child will follow any transformation of his parent,

but it's transform channel won't be modified.

And this is because transform channels

output the local space coordinate of an object.

Transform channel are read in sequence

with location first, then rotation, and finally scale.

You can use the gizmo in local space

to make your manipulation easier,

but don't rely on them to figure out the orientation

of your object.