If you've seen more than a few Pixar movies, you know that not everything is what it seems: Bugs can be cuddly, monsters can be friendly, robots can be full of heart and soul. 
The movies themselves defy expectations, too. Despite all appearances – the bright colors, the too-cute jokes, the googly-eyed characters – Pixar films aren't child's play, not just in terms of the story (don't lie, you cried during the first 15 minutes of Up, too), but in terms of how they are made. 
Toy Story, Finding Nemo, and other modern animated movies aren't just flip books on film. 
"Today's cartoons are so steeped in science, computer science, and mathematics," says Frederic Bertley, senior vice president of Science and Education at the Franklin Institute, the host of "The Science Behind Pixar," running Saturday to Sept. 5. 
When Sully lumbers through a scene in Monsters, Inc., for example, the 2.3 million hairs covering his body need to look good and move realistically. And they do, thanks to powerful animation software created by Pixar that simulates the movement of hair and clothing according to the laws of physics, guiding all of Sully's fur as he moves. 

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"The Science Behind Pixar" gives you a behind-the-scenes look (and in some cases, a chance to take control of the scenes) at the different steps of making a Pixar film, focusing on the science and math concepts that are the backbone of the tricks and techniques that their animators, artists, and engineers use to make the stories come to life. 
The exhibit, created by Pixar and the Boston Museum of Science, and now on a multi-city tour, throws visitors into the studio's production pipeline. Eight different sections of the exhibit are spread out over 14,000 square feet in two rooms. There, you'll learn about the different aspects of Pixar's craft, and try your hand at it as well, with physical and digital interactive aspects of the exhibits. 
In "Rigging," learn about the virtual bones, joints, and muscles inside your favorite characters that let them move the way they should, and the underlying math that lets Pixar animators pose and move them quickly and easily.
(Speaking of quick and easy, there are two or three copies of almost every exhibit station, which may cut down on wait times.)
In "Rendering," you'll see how a virtual 3D scene from Inside Out becomes a 2D image for the movie screen over the course of 29 hours (thankfully, it doesn't render in real time). 
Perhaps most important, you'll get to take selfies with WALL-E, Finding Nemo's Dory, The Incredibles' Edna Mode, and other characters along the way. 
Each new world that Pixar invites us into, whether it's under the ocean or inside a little girl's mind, has its own demands and problems, and each of those has a solution that relies on art, science, imagination, and technology. Such as:
For Cars, Pixar had to deal with a cast of characters made of metal. To keep them looking as shiny as the real thing and not flat and matte like an old Wacky Racers episode, Pixar used "bidirectional reflectance distribution functions" (BRDF) that mathematically describe the way light bounces off a surface. For all the surfaces in the movie, Pixar artists adjusted the BRDF. The function told their computers how shiny or dull the surface should look given the lighting and camera angles in the scene. 
To show us the world from an ant's perspective in A Bug's Life, Pixar had to get down on the insects' level. Technicians designed a tiny video camera, dubbed the Bugcam, that moved around on Lego wheels. The Bugcam was rolled around outside to show the set designers and virtual-camera artists how to design and frame their virtual sets from a bug's point of view. 
The film also featured a lot of grass, too much to animate by hand. To create all the vegetation, Pixar used the equation for a simple parabola (a 2D, mirror-symmetrical curve) to create a curved blade of grass and then used computer programs to vary the equation and the color, height, width, and curve of the individual blades. 
Finding Nemo featured some of Pixar's most crowded scenes, jammed with aquatic creatures. Instead of animating each individual animal, schools of fish were created by a computer program that followed rules Pixar gave it about how tightly packed the fish were, how many groups they were in, and whether they were moving in the same direction.
Merida, the heroine of Brave, isn't as scary as Sully, but the thought of working on her hair probably gave a few Pixar artists nightmares. Merida's red curls would be nearly impossible to animate individually by hand in every single frame, so software engineers developed a hair simulator. They modeled each hair mathematically as a spring, and then used the simulator to control their movements, allowing her hair to bounce and move while keeping it from coming undone. 
Outside the Pixar studios, a challenge that teachers and parents often face is getting kids interested in the sciences, and Pixar may have found a solution here, too. "It's a great platform if you want to get people jazzed about science," Bertley says. "Bring in these wonderful animations that we all love and have this really cool science behind them." 
The exhibit also shows children that there are many science-, tech- and math-oriented career options that don't involve white lab coats, and that mathematical rules and wild imagination aren't worlds apart. With computer science and coding, Bertley says, you can still speak to the artistic side of humanity.