Pixar have brought us some of our most beloved and memorable childhood movies; even as we graze into adulthood and beyond, the familiar stories and characters that Pixar introduced us to all those years ago still give us that warm feeling, indistinguishable from home cooking and the music of our youth.

Pixar and childhood go hand in hand, but, like ourselves and the inevitable pull of growth that comes with time, Pixar has evolved, and, now, looking back at the earlier projects from the animation giant, it's quite extraordinary to see how far they’ve come.

Let’s start where it all began. Let’s talk about Toy Story.

Before Buzz and Woody flew onto our screens in 1995, we had never seen an animation like it. Pre-Toy Story, we had never heard of "computer-animation" or, as it is more commonly known, "computer-generated imagery" (CGI). These CGI rendering techniques used by Pixar were unique to the movie.

What was so different about CGI?

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Truth be told, Pixar were not, in fact, the first set of cowboys to dabble in the computer-generated imagery rodeo, but Toy Story (1995) was the first feature-length film to be solely made using the format. Computer-animation is the term given to the process of digitally generating animated images. One way of looking at it is as the digital successor to the previously used stop motion techniques reliant on 3D models and the traditional animation techniques of creating moving images through frame-by-frame animation of 2D illustrations.

What made CGI the exciting new development of the age?

via: Deborah Coleman/ Pixar- From the collection of Walt Disney photo archives

Well, to explain this, we have to get a bit scientific. The human eye and brain will only be tricked into thinking that an object is moving in a smoothly life-like way when pictures run at about twelve frames per second. Anything below twelve frames per second will reveal giveaway signs of jerkiness, destroying the illusion of fluid motion. Hand-drawn animation typically ran on fifteen frames per second, whereas the dawn of CGI brought animation to speed up to the much superior rate of twenty-four, twenty-five, or thirty frames per second.

Following the innovation of the first Toy Story movie, Pixar came on leaps and bounds.

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Naturally, with any beta model, by the time that the second installment of the Toy Story franchise came round, the software had come on in leaps and bounds.

Let's start with humans.

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In the first Toy Story movie, Pixar hadn't fully figured out how to animate human characters. Animating clothes was incredibly time-consuming. If you look back at the original movie, you'll see that they got around this by mostly showing hands and feet. This works well for Toy Story as it gives the movie the feel of being from the perspective of the toys.

Dimly lit human characters.

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Pixar also got around the issue of developing human animations by choosing to not fully light characters, so that you wouldn't notice any missing details. This works extremely well, and, unless you were looking for it, it's unlikely that you'd notice.

Working on A Bug's Life (1998) before Toy Story 2 (1999), gave Pixar a chance to work on the issues.

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Smoothness was a key element that the animators were able to improve on by working on A Bug's Life. Bug's Life allowed the animators to practice on the smoothness with all of the different kinds of textures used to make the bugs in the movie.

Comparing the humans in both movies, you can really see the difference.

Comparing the human likeness of original Toy Story villain, Sid, and the Toy Story 2 villain, Al, we can see how far the animators had come.

Take Andy's fashion for instance...

In the first Toy Story installment, Andy wears a pretty basic outfit; by Toy Story 2, the animators became much more adventurous when it came to what clothes they kitted out the toy-owning boy in.

Despite the improvements, Pixar wasn't ready for a fully human cast until 2004.

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We witnessed Pixar's first fully-human cast in 2004 with the first installment of the family-based superhero movie, The Incredibles.

Before perfecting human animation, Pixar dabbled in the medium of monsters.

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In 2001, Pixar brought out the first Monsters, Inc movie. This feature-length animation, which followed the story of monsters who scare children to power their city, gave the animators at Pixar a chance to practice a few things.

Like hair. Or, I guess, in the case of Monsters, Inc.: fur.

Monsters, Inc allowed the animators to tackle fur head-on. Hair/fur was always a tricky thing for animators to crack. This is because it involved animating millions of individual parts of a character's body. This wasn't a problem in movies such as A Bug's Life - because insects don't have fur.

Monsters, Inc. helped to improve the fur on Buster the dog in Toy Story.

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As you can see, Buster's fur in Toy Story 2 (1999) was nothing like the standard of the fur in Monsters, Inc (2001).

By the time that Toy Story 3 came around in 2010, Pixar had fur nailed.

When you look back on the opening scenes of Toy Story 3, noticing how far they had come in terms of fur, you get the feeling that the animators were showing off.

Do you remember how poor quality the dog animation in Toy Story (1995) was?

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It may well have slipped your mind, but Buster wasn't the only dog to feature in the Toy Story movies... next door neighbor/toy-mutilating villain, Sid, also had a pet dog. I'm sure that the animation team at Toy Story are happy to leave Sid's dog in the past...

How did they improve the fur?

To develop the animation of fur for the Monsters, Inc. movie, the guys over at Pixar developed software called "Simulation." This program allowed some elements that were too difficult to hand-animate to be motion-simulated.

What did the motion simulation do?

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The software allowed the animators to look at each strand of fur individually. They were then able to estimate each kind of force that could act on these particles. They also considered acceleration and velocity, ensuring that the fur could not only look realistic, but that it could move in a realistic way too.

Pixar was also inspired by real-life animal fur to perfect the look.

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By studying the fur on animals such as llamas and alpacas, Pixar discovered that the best method of creating realistic fur was by clumping it together.

Do you think that Sully has a bit of an alpaca vibe?

Maybe an untrimmed, blue-furred, horned alpaca breed.

Ratatouille (2007) also benefitted from the tricks learned in Monsters, Inc. (2001).

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The rats in Ratatouille benefitted from the know-how learnt from Pixar's earlier releases, as did the dog, Dug, in 2009's Up.

The lessons learned about fur also lent a hand in the animation of nature.

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As seen in Finding Nemo (2003). The moss on the submarines is incredibly life-like; this is no surprise considering the similarities between moss and fur and how far, by this time, Pixar had advanced in this particular kind of animation.

It also helped to develop the greenery in Cars (2006).

Really, every time that Pixar learns something new, every one of their later movies benefit.

Finding Nemo (2003) provided Pixar's animators a new challenge to tackle...

With the movie set mostly underwater, Pixar's animating team had to work out the best way to make the underwater world come to life.

Just like with fur, the team looked at real-life examples to build the best image.

According to Director of Photography, Danielle Feinberg, the team started with a real-life underwater clip, recreated it using the computer, and broke it down to find the most essential elements.

The light was also very important to the animation process of Finding Nemo.

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The team had to think especially hard about light and how it traveled through the water. The light affected both the visibility and the color of the movie's underwater world.

Hank the Octopus in Finding Dory (2016) was the most difficult creature to develop.

According to the character supervisor, Jeremey Talbot, in order to make Hank come to life, the animators had to break down an octopus and put it back together again.

That might not sound impossible but...

The task was so arduous that developing just one scene that involved Hank took the team two years.

With every new challenge, Pixar makes fascinating animation discoveries.

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For instance, when animating Hank, the team discovered that octopus tentacles don't bend, but, instead, unfurl. One engineer spent six months getting the curve of one of his tentacles right.

How far Pixar has come.

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When Cars 2 came out in 2011, Pixar had one thousand times the computing power that they had when making the original Toy Story in 1995.

So what's next for Pixar?

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With Toy Story 4 hitting theatres this summer, what can we expect next from Pixar? Pencil June 2020 into your diaries, for the exciting new picture, Soul. From the same creative director of Monsters, Inc., Up, and Inside Out, I am confident that this will be a good one - Peter Docter will not disappoint.