Explore Pixar's Science

Explore The Science Behind Pixar's Movie Magic

Animated films spring to life as a creative fusion of art, technology, and science. Here are four examples of how science come into play when Pixar creates their animated films.

Let’s say, you want to make an animated film just like Pixar.

First, you’ll need to come up with a really good story that children and adults alike will enjoy and empathize with.

You also need to develop the characters in your story. What do they look like? What are their personalities like? Are they related to each other? Is there a villain?

Next, you’ll need to develop the world where the story will take place. What is it like? How are the landscapes, the vegetation, and the weather like? Are there any cities? What characterizes the animals and the people that live there?  Is it perhaps an alien planet filled with strange aliens and organisms that no one has ever seen before or even thought of?

You will have to design and build all of it (and so much more) in a computer – from scratch!

Every hair on your characters’ heads or in their fur coats. Every single blade of grass and every single ray of sunshine that flickers through the trees or through the water. All the stars and clouds in the sky, lamp posts, coffee tables, sand pebbles, T-shirts, one-eyed green monsters … everything!

Mike fra Monsters University

Monsters, Inc. portrays a world very muck like ours, but it is filled with monsters like Mike Wazowski.

And of course, it not only has to look believable – it must also move in a believable way.

As you can probably imagine, Pixar has hundreds of skilled professionals collaborating to make it all happen.

A Combination of Art, Science, And Technology

Pixar was first to make the jump from traditional hand-drawn cartoons to modern animated films. In 1995, Toy Story premiered as the world’s first cinema-length animated film made with computers. The shift from drawing cartoons by hand to using computers and software was nothing short of a revolution.

Toy Story was so popular it was followed by three sequels.

Pixar’s animated films are made in a creative interplay between art, technology, and science.

The process starts with the conceptualization and development of the story, the universe, and the characters.

This primarily artistic phase is followed by a fixed process of eight phases – the exact same eight phases you can now explore in The Science Behind Pixar: Modeling, rigging, surfaces, sets and cameras, animation, simulation, lighting, and rendering.  And of course, in the end we have the finished movie.

At Pixar, we use science, technology, engineering, art and math – along with a significant dash of creativity and fun – and The Science Behind Pixar is truly a great demonstration of how all those ingredients come together in our filmmaking process.”  –  Jim Morris, President, Pixar Animation Studios.

Pixar has produced 26 animated films so far – and more are on the way. Every film has challenged Pixar in new and different ways.  But all these challenges have been solved through art, technology, and science.

But before we dive into all the science, let’s briefly touch upon art and technology.

Art And Animation

Pixar’s animated films are first and foremost artistic products.

Art comes into play in Pixar’s great storytelling. Here toys come alive, cars have eyes in their windshields, and monsters scare children because they use screams as an energy source.

Art is also vibrantly present in the visuals – especially in the design of lifelike characters such as the loyal toy cowboy Woody, who’ll do anything for his toy friends and their owner Andy. It can be a toy, a fish, a car, or even a feeling, like in the movie Inside Out, Pixar makes them all spring to life.

Pixar’s artists are especially involved in the beginning, where the film’s idea, story and characters are developed. They use both classical artistic methods and materials, such as pen and paper and clay. They of course also use computers and software.

Here you can se how an artist’s sketch inspired a scene in Monsters, Inc.

It takes a lot of sketching and drawing. Pixar’s artists produced a whopping 286,491 drawings while working on the story for the film Coco, where a young boy, Miguel, visits the afterlife on the Mexican holiday Day of the Dead.

Click here, if you want to see more amazing character designs from Coco.

Technology And Animation

Pixar’s animated films may first and foremost be artistic products. However, they just wouldn’t be possible to make without the right technology.

Pixar uses powerful computers and advanced software, such as Maya Autodesk and Renderman, which enables Pixar to create amazingly complex universes and animations that could never be recreated by hand.

But a Pixar film is not one long flowing animation, as you might think. In fact, Pixar’s films are made up of tens of thousands of single images, called frames, which are then displayed in sequence at 24 frames per second. 24 frames per second is enough for your brain to perceive it as one fluid motion.

The film Toy Story consists of 114,240 single frames. All these frames were rendered, i.e., translated from the all the 3D information and programming in the computers into the 114,240 2D images that would eventually be shown on the screen.

Rendering is very time consuming and requires very powerful computers. For Toy Story Pixar’s computers were rendering for a total of 800,000 hours.  That’s the equivalent of 33,333 days or 91 years – if Pixar only had one computer to do all the work.

Computers are getting faster and the software more sophisticated all the time. Today, Pixar could render Toy Story in less time than it takes to see the film.

The technological leaps make it possible for Pixar to create wilder, more vivid, and more detailed animated films. In other words, technology drives animated films to become more and more complex and therefore it is still very time consuming to render a Pixar film.

But what role does science play in all this? Let’s take a closer look at four examples of Pixar science.

1. From Idea to 3D – Biology and Geometry

From the brave Space Ranger Buzz Lightyear to the little clownfish Nemo, Pixar’s characters all begin as an idea.

The artists at Pixar develop their ideas by sketching. They draw by hand and on the computer – and work their way into the characters’ personality and appearance.

Pixar’s characters often seem like they have just sprung from someone’s uninhibited imagination – and indeed the artists at Pixar are extremely imaginative. But they are also skilled at observing reality, and they know how the bodies of animals and people look like.

The creation of a character requires great observation skills and an insight into biology – especially knowledge about anatomy, which is the study of the external form and internal structure of living organisms. This also applies to monsters or aliens. Even though their bodies might look strange and otherworldly they are generally imaginative variations of people, animals or plants that exist right here on earth.

Let’s say that the character is a bear, then the artist may spend several days in an animal park drawing sketches of bears. What makes bears special? What are the characteristics that allow us to immediately recognize it as a bear? How does a bear look like when it walks, sniffs, eats, gets angry or plays around having fun?

A bear in a Pixar movie will not be a 100% realistic bear. Perhaps it has human facial expressions, it may speak, wear clothes, or it might have a head that is far too big for its body. But we can still clearly see that it is a bear. The artist’s ability to observe, knowledge of biology and anatomy and, of course, good artistic craftsmanship will all be coming together so that we immediately recognize it as a bear.

In the same way, knowledge of botany, geology and meteorology can help Pixar’s artists design vegetation, landscapes, and weather for the fictive universes that the film’s characters populate.

When the design of the character is complete, a sculptor takes over. The sculptor’s task is to sculpt the character in clay so it can be seen it from all angles and in three dimensions.

The small, modeled clay figures are also called maquettes, and you can see a collection of them in The Science Behind Pixar.

The Science Behind Pixar exhibition includes an entire collection of maquettes.

When the clay maquette of the character is finished, a digital sculptor takes over and sculpts it inside the computer using mathematics. The result is a perfect digital copy. The digital 3D model of the character takes on the same spatial shape as the maquette, but it looks quite different.

The digital sculptor uses spatial geometry. Space geometry is a branch of mathematics that includes, among other things, the calculation of surface areas and the volume of spatial objects.

All points in a three-dimensional space can be defined by three numbers, which are expressed on three axes X, Y and Z. When you have the three numbers, you know exactly where the point is in relation to everything else in this three-dimensional space.

Buzz Lightyear’s evolution from artist’s sketch over wireframe mesh to finished 3D model.

The digital 3D model made by the digital sculptor consists primarily of points that are all defined on the X, Y and Z axes.  Between the points run lines connecting them in what’s called a wireframe mesh. The character is now described in terms of points, lines, and the polygons they form.

The wireframe mesh is more complex and denser in the areas where the character needs to be most detailed. Pixar uses mathematical algorithms to create more points and thus make the wire mesh more dense. This makes the 3D model extra detailed and more organic to look at.

This is the first step in bringing the character to life in Pixar’s computers. But the character must also be able to move.

2. Animation – Biomechanics and Mathematics

Inside your body there are bones, joints, and muscles. Together, they give your body structure and enable you to move.

When a rigger at Pixar builds a rig for a character, it is fitted with a set of virtual “bones”, “joints” and “muscles” that allow the character to be moved easily and efficiently in the computer.

But there is a big difference. You have 639 muscles and 206 bones in your body, but a Pixar character can be rigged with thousands of “muscles” and “bones”.  Mike from Monsters, Inc., for instance, had a whopping 7,000 in his rig — even though he’s practically just a two-legged head.

To build a rig that fits the character’s body, a rigger must have a deep understanding of anatomy – and especially of biomechanics.

Biomechanics is the study of the mechanical laws relating to the movement or structure of living organisms. When you walk, it’s not just your legs that move. The movement spreads through your body like ripples through water, making your head bop and your arms swing as well.  Your joints bend, turn and stretch and your muscles and tendons work under the skin to moving your bones.

Consider for a moment how your body and face move when you sneeze? If you were frozen in time in that split second when you sneezed, your friends might have a hard time even recognizing you – your face would be completely twisted. Fortunately, a sneeze is over so fast that no one has any doubts.

But all that means that your body changes shape as you move.  The same also goes for Pixar’s characters when they move – Pixar calls it deformation.

See how many expressions you can make when you control the eye rigs of Jessie from Toy Story 2.

In other words, a good rig makes it possible to move a character’s body in a natural and easy way. When this is accomplished, Pixar’s animators take over.

The animators are the real “actors” in an animated film since they are tasked with bringing the characters to life through programming.

When the animators move the characters, they begin by defining the so-called Key Frames.  These are the most important moments in the movement.

Let’s say an animator is tasked with making Mr. Incredible from the movie The Incredibles jump. Some positions in that jumping movement will be more important than the rest. It’s important to know where Mr. Incredible begins the jump, how high he jumps and where he lands. It is also important to decide how he will look in these positions.

Once these key positions are defined, the animator can use mathematical functions, so-called splines, to calculate the movement between the positions. This is of course done in a computer program that performs the complicated calculations.  The result is a smooth movement that the animator can adjust to make it look exactly as desired.

Although the goal is for all movements to look as natural as possible, the animators often choose to exaggerate the movements to evoke a sense of humor and show the characters’ personality and emotions.  When Mr. Incredible jumps, the animator may want the audience to sense the character’s incredible power or perhaps that he is sad or getting tired.

3. Surfaces – Memory Hack, Physics and Math

When we look at an object, we can see its shape and colors. We also instinctively know or have a general idea of how it would feel if we touched it. We can see if the thing is new or worn. We can see if it will feel cold or hot or perhaps dry or wet.  We can “feel it” with our eyes, without having to use the sense of touch.

We can do this because we see through the filter of our previous experiences. Pixar taps into this memory “hack” of our sense of touch in all their films – and they are masters at creating believable surfaces.

Want to know more about surfaces? Watch a short Pixar-video here.

Pixar’s surfacing artists use the so-called shaders, i.e., software that create colors, patterns, and textures in the surfaces of all 3D shapes.

If you play computer games, you’ve probably heard the term “skin”. Shaders are a form of “skin” that wrap all the shapes in Pixar’s films.

If you were asked what color Lightning McQueen is in Cars, you would probably answer “red”.  But in fact, he’s 14 different versions of red in the film — from shiny and new to dirty and dusty — and it’s all created with shaders.

Lightning McQueen in his shiny red color.

Because the surfaces are just a “skin” on the 3D figures, it’s a simple exercise for Pixar to change or replace the surfaces. Lightning McQueen could easily swap his shiny red “skin” with the one belonging to the rusty tow truck Mater. But you could also make them both look like they were made from peanut butter.

A shader also calculates how light is reflected from the surface of the object, and this is one of the most important tools in creating believable surfaces.

Pixar’s surfacing artists use a mathematical model that they call BRDFBidirectional Reflectance Distribution FunctionBRDF is based on formulas known from Physics that are used to calculate how light is reflected from surfaces in the real world.

The use of shaders makes a huge difference. Here you see a before/after image from the film Cars 2.

BRDF calculates how light interacts with the surface texture, color and how transparent the object is. If the surface is very glossy or smooth, then you will see a shiny spot of light where the light is reflected directly towards you.  This is also called a highlight.  If the surface is matte or uneven in its texture, you will not see a highlight, but primarily just the color of the object.

Try you hand at creating surfaces with BDRF in this fun online activity. 

With BRDF, Pixar’s surfacing artists can create the illusion of any type of surface, such as wood, plastic, metal, glass, cake, or human skin – and it all looks so real that you can just “feel it” with your eyes.

But it does require tremendous amounts of raw computing power! In the movie Cars, it took millions of calculations to create all the reflections in the cars’ glossy paint.

4. Simulation – Mathematics and The Laws of Nature

Animation is very time consuming. An animator can only animate about 4 seconds of a character’s movement per week. Pixar’s animators therefore focus most of their efforts on animating the most important characters.

Luckily, Pixar has pioneered and perfected the use of mathematical algorithms for automated animation. This is called simulation.  Simulations save time and can perform incredibly complex animations that a human would never be able to do.

Hair, fur, or clothing can be programmed to follow the character’s movements, flutter in the wind, or get wet. Simulation is also used to create liquids, smoke, and fire.

In the film Finding Nemo, Pixar had to create the illusion of an underwater world. This included developing simulations of the surface of the water, water droplets and foam. Pixar even simulated the East Australian Stream from 1,161,344 “water particles”.

The simulated East Australian Stream plays an important role in the movie Finding Nemo.

Pixar also simulates many of the characters you see in the background in the movies.  In the film Coco there are 21,633 spectators in one of the scenes – all of them were simulated.

In The Science Behind Pixar you can try simulating a lawn and a school of fish by manipulating the algorithm behind the simulations.

Now, it may all seem as simple as “a push of a button”, but unfortunately that’s not the case.  A very precise framework must be set for the simulation algorithm to ensure that the result looks believable.

Pixar’s programmers must have a very good grasp of the laws of nature that govern our universe.  When they program a simulation of a liquid, it must also behave like a believable liquid – and as you know, water flows and behaves completely differently than oil. It would also be strange if a feather fell like a bowling ball instead of gliding softly through the air gently pushed by the wind.

Gravity, movement, balance, weight, and friction – everything must seem as if it behaves “natural” in relation to the laws of nature and the particularities of the specific universe that Pixar has created.

It is often quite easy for you to see if Pixar has hit the right spot.  And if not, the illusion will be revealed and you’ll have a hard time empathizing with the story.

Princess Merida and her unruly red curls from the movie Brave.

Take for example, Princess Merida’s red curls in the movie Brave.

Pixar’s artists had designed Merida with wild and unruly red curls to emphasize her brave and untamed personality. But Pixar had no previous experience in how to create wild and curly hair.

Pixar therefore had to examine how curls behaves in real life.  They found that a lock of curly hair behaves much like a spring when you pull on it and let go.

This was good news, because in physics there is a formula, Hooke’s Law, which can be used to calculate the force of a spring when you either pull it or press it together.

Pixar’s programmers could use this knowledge to create a mathematical model of a spring in the computer. They could now simulate a lock of curly hair as if it was a spring.  Merida got an entire scalp full of simulated hair-springs.

Visit The Science Behind Pixar and lear more about how Pixar solved the problem with Merida’s curls.

But unfortunately, the simulated hair-springs turned out to be too loose. When Merida moved around in the scenes, her hair flew around her as the hair springs were pulled out way too far.  When she stood still, the springs simply slipped out of shape. The simulated gravity simply pulled the curls out of her hair and made it straight.

Pixar came up with a brilliant solution. They programmed small invisible springs inside the curls.  That gave Merida perfectly unruly curls that moved naturally.  So, Merida’s beautiful red hair is in fact simulated springs with many small invisible simulated springs inside.

Discover More Science in The Science Behind Pixar

These were some of the scientific disciplines such as biology, physics and mathematics that come into use in the creation of Pixar’s movie magic.

When you visit The Science Behind Pixar, you can go in search of other examples of how science comes into play as you explore the 65 activities in the exhibition.

We look forward to seeing you!









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