from Pixar's latest movie, "Soul."

Even though it's animated, everything about

how the fingers float from one key to another

to the small details like tendons moving in the hand

feels just as real as

the reference footage that inspired it.

While Pixar has used reference footage since the beginning,

it could not have pulled off a scene

with movement this nuanced and realistic

back in 1995 for "Toy Story."

And it took years of technological breakthroughs.

So how did Pixar get here?

First off, they have an army of animators and riggers.

We talked to seven who worked on "Soul"

to see how far Pixar has come.

Let's start over 26 years ago

with the technology built for "Toy Story."

Getting a given character to move

starts in Pixar's rigging and modeling department.

Whenever you're thinking of a character model

before it's rigged, it's in a completely neutral pose.

There's no expression on the face.

The arms and legs are all straight.

And so the controls that we put in in rigging

lets parts of the body move like you would pose

like a doll or a puppet.

To get a clearer idea of the basics,

let's start with this character model of Woody.

The rigging department will add the rig,

which is essentially an inner skeleton.

Throughout this rig you can see all these controls

called animated variables, or avars,

which animators use to make

different parts of a character move around.

This early version of Woody had 596 of those controls,

which may seem like a lot,

but by 2019's "Toy Story 4," Woody had more than 7,000.

To make things a little more complicated,

one control point is often connected

to other control points.

So moving one in the eyebrow

will move the wrinkles on the forehead.

Adding more controls to these "Toy Story" characters

would have let them move with more nuance,

but back then, Pixar was making a brand new rig

for every single character.

That would change with "Toy Story 2."

Pixar introduced Geppetto, later updated to Presto,

which allowed animators to reuse

and adapt rigs for multiple characters.

This sped up the animation process

and gave animators more control

over movements and facial expressions.

The new software provided a template of two-legged

and four-legged rigs that could be altered

depending on the specific needs of a character.

According to rigger Jared Fong, the sea lions

in "Finding Dory" were actually constructed from dog rigs,

with legs folded into flippers.

More control with Geppetto also meant

more expressive facial movements,

as seen in 2003's "Finding Nemo."

To really nail the character's emotions,

animators used reference footage.

Now fish don't have eyebrows or eyelids,

but eyebrows are so important for expressing human emotions.

So animators decided to add eyebrow-like lumps

to characters like Marlin and Dory.

And replicating real facial expressions

meant connecting more control points with each other.

You can see that with Dory. The control points

around her mouth are connected with her eyes and her cheeks,

giving her a more believable smile.

A smize, if you will.

After making major strides with toys and sea creatures,

the most daunting challenge was yet to come: humans.

Mr. Incredible consisted of 426 primary controls,

111 secondary animation controls for more subtle movements,

and 1,061 modeling controls

for sizing and other adjustments.

Thanks to Geppetto, the rigging and modeling team

could perfect Mr. Incredible

and then reuse his rig for other characters.

And to really make his movements realistic

they used full-body reference footage.

For example, this clip where an animator

lifts up this exercise ball

was helpful for moments like this,

where Mr. Incredible lifts up an Omnidroid.

And the team didn't animate just a rigid skeleton.

On top of the skeleton was a layer of muscles,

which could bulge and flex.

And the skin on top of that

would need to respond realistically.

So Pixar developed a new system called Goo.

This allowed the animators to see the skin

and muscles react in real time as they worked,

allowing for greater flexibility and movement

and more control over how humans move.

Goo led to breakthroughs in moving

more challenging body parts, like the shoulders,

which were more primitive in earlier films.

The Buzz Lightyear shoulder's a ball and socket.

Woody's shoulder is just a stitch line.

He's got no shoulders, right?

That arm just hinges.

Mr. Incredible has a big old strong shoulder.

How you get a trapezius muscle there in the shoulder,

and how it moves in the pectoral, really complex stuff.

The rigs built for "The Incredibles"

were designed to let the characters

stretch further than the average human.

Which was important for Elastigirl,

who needed to transform into all shapes and sizes.

And just like how superheroes

needed to react to forces like gravity,

so too did the cars in Pixar's next feature, "Cars."

Pixar extended its technological boundaries yet again

with a system called ground locking,

which made sure the cars always stayed on the same path,

regardless of terrain,

without animators having to move them frame by frame.

We had to have our characters

be able to follow the contours of the ground

without having to animate them,

like up and down if it was like, a rolling hill.

So it's going to move along these things.

And then we're going to animate on top of that.

Because of ground locking,

Lightning McQueen could now drive smoothly on a flat road

that turns into a very windy path automatically.

This may seem like a specific advancement

just for the "Cars" movies, but it would be important

for some of the most memorable characters in "Soul."

By 2007, animators could have

up to 150 controls in the human face.

So they could give characters a much wider range of emotion.

Perfect for a movie like "Ratatouille,"

which is largely set in the human world.

All these intricate controls allowed for

the complex array of expressions seen on Chef Skinner.

Look at how far Chef Skinner's mouth extends

as he's yelling at Linguini.

According to supervising animator Mark Walsh,

the tech wouldn't have been able to handle such a stretch

in "Toy Story" or "Finding Nemo."

The groundbreaking muscle work in "The Incredibles"

allowed animators to give Linguini

more spontaneous movements in the scenes

where he's controlled by Remy in the kitchen.

By the time "Toy Story 3" came out in 2010,

Pixar's animators had gotten such precise control

over how characters move, that it's surprising

they'd want to take a step backward.

But they actually relied on fewer controls

to better replicate the trademark toy movements

audiences knew and loved.

If a character has a limited range of motion

in its shoulder, what we'll do is we'll basically

lock off some of that range of motion,

and then that forces you to animate it in a different way.

They still had room to pick and choose

what they would keep about the old characters

and where to elevate them.

For example, they could have put 25 controls

in each of Buzz's eyebrows, but decided to keep them simple,

like when he had just three per brow in the original,

while also giving Spanish Buzz

these complicated flamenco-like moves.

There was one particularly hard toy to animate:

the octopus named Stretch.

Despite the innovations in stretchiness

from "The Incredibles," making eight tentacles

stretch and curl was still a daunting task.

We're fighting against the computer.