All language subtitles for 05-08-Polishing the Torso

- [Instructor] In this video,

we are going to polish the
torso of the character.

Since it's pretty subtle on the run cycle,

especially for a light character,

I like to start with the left
to right location motion.

So basically whenever your character

is contacting with the crown,

the contacting leg will
first absorb the impact

and then push the character up,

but also a bit on the opposite side.

Your character should be moving
to what the contacting foot

one or two frame after the contact,

so that he has time to
compensate the momentum

of the previous move.

Then there will be an
acceleration during the pushing

toward the other side.

And when the character is airborne,

my go-to is to use a linear curve.

But there won't be any noticeable dumping

while your character is in the air.

There is no opposite force
to absorb the momentum

of the side to side motion.

So in our case, the
contacting frame is frame two

and frame 14, then takes two
frame to get to the extreme.

And then as the character is pushing,

his body is moving on the other side.

Once you are done with
the side to side motion,

we can work on the forward
and backward motion.

People, and myself included,
often forget to add forward

and backward motion to the torso root.

It's not a big deal if you forget to,

as it's gonna be pretty subtle,

But this slight variation
will bring a bit of texture

to your run cycle.

The rule is pretty simple.

As your character is falling forward,

as the torso is getting down,

his torso root will
slightly shift forward.

During the pushing pose
and while he's airborne,

torso root will slightly travel backward.

So if you have a look to the Y curve,

you can see that the
values we are working with

are very, very subtle.

So whenever you are checking
the curve as a reference,

don't forget to check out
the values on the left side.

To make the X rotation
motion a little more obvious.

I've parented this stretched
tube to our torso controller.

If you focus on the tip of this tube,

you will be able to clearly
see the rotation motion.

The X rotation drives the
leaning forward and backward

of our character torso root.

What I want to emphasize here
is that whenever the character

is pushing on his leg, his
torso is leaning forward.

Think of a lion jumping,
pushing on his root

with his shoulder inward.

Then he will reach his highest point,

and as he fall down, the
shoulder or the upper torso

will kind of drag behind the root,

and so, the X rotation
will go the other way.

While this rotation motion
should be noticeable,

don't over-commit and input
too high rotation values,

because on top of this,
we will also add rotation

into the chest controller.

And as the chest controller
is inside of the torso root,

it will rotate even more.

A quick tip, whenever you are
working on a chain like this,

I will deactivate the chest controller,

this way, the upper body
rotation of my character

is only driven by our torso root.

And it makes it easier to read the motion.

The second tip regarding this motion

is that since our character
is taking two step

during the whole cycle,
we just need to work

on all of the cycle, and then
we can duplicate the curve

onto frame 12 to 24.

Another good practice
I should have shown you

at the very beginning of this video

is to hide the arms of the character.

Since we are not working
on the arms at the moment,

they can be a bit distracting
and training-wise,

it is good for you to only see the torso,

so that you will get used to its motion.

As usual, we are not into a linear close,

so I will jump onto the
hips before I finished

to polish the rotation of the torso root.

The first thing I check is
which channel I will need

to twist the hips, and it's
the Z quaternion channel.

The twisting is the simplest motion

regarding the hips motion
since it follows the legs.

So when the left foot is
forward or left leg is forward,

the Z curve is pushed down,

so that the hips are twisting
forward on their left side.

And during the passing pose,

the hips will twist the other way.

So we have a pretty smooth
curve with a slight plateau,

as we are favorizing the
airborne pose of the character.

So it's a moment where the hips
are not twisting that much.

And then we transition
from one side to the other

during the passing.

The next hips motion we will work on

is the left to right tilting,

and it's one of the most
important motion of the hips.

It's not the easiest one to get right,

because too much tilting
will look very feminine,

while not enough will look very stiff.

This motion is mainly driven
by the Y rotation channel.

And what we do want to emphasize

is the pushing of the legs on the hips.

So I'm slightly reducing
the amplitude of the curve

so that I can then re-increase it

during the pushing on frame four.

So we have our contact pose
on frame two and frame 14,

and on frame four and frame 16,

we need a quick rotation
change or shifting,

this way we can fill the
impact of the contacting frame

and the fact that the hips
will react with a slight delay.

In between those two impact motion,

the hips are smoothly
tilting the other way.

As always, for all our cycle,

just make sure that your
frame zero and your frame 24

are the same by duplicating them.

Now our hips motion start
to look pretty good.

We can now polish the
body, X rotation axis,

which will be the tilt
forward and backward.

This one is pretty easy to get right.

As the leg reach the contact pose

and switch to the passing pose,
the hips will tilt forward.

And then during the
pushing and the airborne,

they will tilt backward.

Just imagine that the hips

are currently pulling the front foot,

so when contacting the ground,

the hips will surge forward for the foot,

and then when pushing and going up,

they will pull the foot back.

This motion is linked to
the extradition of the top,

so we have already polished it,

so you can keep it very subtle.

Again, don't forget to double
check the graph editor values.

While the X rotation curve
looks pretty contrasted,

the range of value we are
working on is very small,

so in the end, the X
rotation is not that big.

As we have slightly modified
the orientation of the hips

during the motion, we can see
that on the contacting pose,

the leg are not full straight.

While it may look a little more natural,

as explained in the
beginning of this chapter,

it's better to have an
exaggerated pose for the contact.

So I'm just getting back
to both foot controllers,

and I'm slightly offsetting
the Y location curve

on the contact frame for both feet.

As our hips are now polished,

we can jump back onto
the torso controller,

work on the zero rotation channels,

that is the twisting of the body,

but will be very close to what we have

on the zero rotation of the hips.

They will be just out of frame of delay

compared to the hips twisting.

But the torso twist and the hips twist

are kind of the same behavior.

The fast twisting during the passing,

where I switch from one side to the other,

and then some kind of plateau

where we have a slight overshoot

when our character is airborne.

Once you are done with
the twisting motion,

there is a bit of tilting
left to right also.

So we have to play on the
Y quaternion rotation.

I do advise you to keep it super subtle,

because if you push the
tilt left to right too far,

your character will look out of balance

or its run cycle will look a bit sloppy.

That could be a good call for
a Hulk-ish kind of run cycle

or a knock or a big barbarian,

but for our character,
that would be too much.

So in the end, you can see
that the range of motion

is pretty limited, and I'm
just smoothing the curve.

The W rotation has almost no influence,

so I haven't worked on this curve.

And in the next video, we will
work on the chest controller,

the neck and the head.