When you think of Pixar, you might not immediately think science unless you’re looking forward to more science fiction fun from the Incredibles. Yet a lot of math and physics goes into each Pixar film and “The Science Behind Pixar” which originally opened in Boston, at the Museum of Science in June of 2015 and then stopped in Philadelphia at The Franklin Institute is currently in Los Angeles at the California Science Center until April 9, 2017.

The exhibit begins with a five-minute video where Pixar technical artist Fran Kalal and story artist Alex Woo explain the basic process of Pixar’s animation features. Inside, the production pipeline is further explained by 40 exhibits divided into eight sections: modeling, rigging, surfaces, sets and cameras, animation, simulation, lighting and rendering.

For the star-struck selfie photog, the exhibit includes life-sized statues of Buzz Lightyear, Dory, Mike Wazowski and his best bud James P. Sullivan, fashion doyenne Edna Mode and that adorable robot WALL-E. Dory is part of the “Explore lighting with Dory” segment where you can change the lighting colors to see how it changes mood and appearance.

Yet as the title indicates, the exhibit shows how basic algebra, trigonometry, geometry, calculus and physics helped bring amazing computer animation features to the screen from the original 1995 “Toy Story” to the recent “Finding Dory.” The Emeryville, California-based Pixar was founded in 1996 so that’s 30 years of filmmaking and software development.

According to Tony DeRose, senior scientist at Pixar and Research Group Lead,  a team of six to seven Ph.D.-level scientists develop new techniques for future films. His team built hair simulator for Merida’s hair.

In the 2012 Disney Pixar feature, the princess Merida is a spirited Scottish lass with masses of wild corkscrew curling red hair. The exhibit’s “Pixar’s Simulation Challenge” explains the problem and the solution was to make each lock a spring. That simulation is Pixar VP of Production Thomas Porter’s favorite part of the exhibit. “Springs are an introductory physics problem,” he explained.

Porter was part of the original group computer tech group at Lucasfilm’s Computer Division that eventually left and formed Pixar. As part of different Pixar teams, Porter shares three Academy Awards for Scientific and Engineering for developing RenderMan software  in 1993, for more pioneering inventions in digital image compositing in 1996 and for pioneering efforts in the development of digital paint systems used in motion picture productions in 1998.

Some of that technology is one display. A simulation from “A Bug’s Life” allows you to see how even something as simple as a blade of grass (a parabola) and a few changes can make a scene change. Then there are separate simulations mood lighting in a room or underwater. DeRose’s favorite simulation in this exhibit is how changing variables can change the behavior of schools of fish swimming.

DeRose got his BS in physics from UC, Davis and then received his Ph.D. in computer science from UC, Berkeley. If you want to excite kids about the potential of science, he recommends coming to the exhibit where Pixar is “really trying to pull back the covers on different creative challenges.”

DeRose was one of the two science advisors from Pixar for this exhibit. “We don’t know how to design museum museum exhibits. They (Boston’s Museum of Science) knew how to deliver ideas and concepts in a way that would be engaging to visitors.” He’s really proud of how high the quality of the interactions are and that it is explained in a way “that is really accessible.” He commented, “It’s all authentic, not dumbed down.”

Each Pixar movie has a challenge. “In the early films, there were lots of challenges. I started around the time of ‘A Bug’s Life’ and ‘Monster’s Inc.'” DeRose explained. “We didn’t know how to tell a story with humans. The humans in ‘Toy Story’ weren’t nearly as effective on screen as the toys. The skin didn’t look right. We had to develop the technology to make skin soft and squishy.” DeRose added, “You might have noticed that more recently, the imagery that we’re creating is warmer, more subtle, more organic, more believable.” What happened is the scientists of Pixar gained an understanding how light bounces around in the environment.

How do you make skin look like skin? DeRose explained, “Light, when it hits human skin, it actually goes inside and bounces around a while. As it’s bouncing around, it’s picking up the color of blood vessels.”

Other challenges come up unexpectedly. Lindsey Collins, producer of “Finding Dory” and VP of Development, doesn’t come from a technical background. Her experience had been with more traditional animation. She laughed recalling that she originally thought a rendering farm was like a petting zoo instead of a place where computers process computer generated imagery. With “Dory,” she “naively said there’s going to be an octopus. Literally, everyone went pale. They immediately knew” this would be one of the “most complex animation rigs to come up with” because the creature has no skeleton. As the software people did their work, they came back and asked just how sure she was that this octopus would be in the film. Some characters get cut before the final movie such as Jack the Ankylosaurus that didn’t make it into “The Good Dinosaur.”

Of course, fans of “Dory” know that the “septopus” Hank, did make it into the movie. Collins then revealed that some of behind-the-scenes development was the animators and technical people inspiring each other. When she saw how Hank would look climbing monkey bars, she felt that had to be included somewhere. Hank has an additional problem: How to give Hank “expressiveness without a nose, without a mouth.” Hank got to be a bigger and bigger part of the story. That meant the “facial” muscles needed to be more human like so the audience could relate to Hank as in the initial scenes when Hank’s face and body is partially obscured as he hides in the sink.

Collins had not been directly involved in the making of the exhibit. “I’ve been aware of it and seeing it come together from afar” but the day before the Los Angeles press view was her first opportunity to walk through it. “It’s compelling to move the knobs and see how this pretty heavy technical job is translatable” and she admitted that some of the displays helped her better understand the science and complex math that her team had previously explained to her.

Not everyone on the Pixar team are scientists or engineers. The exhibit includes individual interviews that shows how team members come from diverse areas: music, painting, fine arts sculpting backgrounds, etc. Collins’ advice to people interested in working in computer animation: “Ask tons of questions. I think it’s really important for kids to be unabashedly curious.”

The research teams, continue to ask questions, some they only partially answered before. DeRose noted that currently one of the problems his team is working on includes simulating water on a small scale, like wine in a cup. “Currently, we tend to lose volume as the simulation runs. The simulation is not conserving volume. You don’t notice it if you have large scale simulations.” That was problematic on “The Good Dinosaur.” Pixar “could not use the same simulation for the whole massive river and for the close up shots.”

Even when solutions are found, not all simulations remain true to the facts of physics. “Science is a series of approximations. In math, there are beautiful well understood proofs that will always be true.” That’s not so in science and even less so in computer animation where DeRose noted, “Physics, for us, is a starting point for building software that artists can use to build that on the screen.” The world was we see it results from an infinite number of bounces of light, but a director may only really need a few.

Sometimes, changes will be made in a simulation. As an example, DeRose explained, “If a shadow is falling in the wrong place,  you could move the light source to fall in a place that the director likes more but that’s going to change a lot of other stuff. A lot of times, we’ll just change the simulation so that the shadow moves so basically the rays aren’t falling in straight lines any more.” In animation, “we don’t have to stay faithful to physics.”

Want to inspire children to learn STEM with animation? DeRose said, “I’m a big fan of project-based learning. Formulate it as tangible goals that the director’s asking you to do, start to break it down into derivatives. From the derivatives, kids can see how the concepts are used, how the concepts are discovered.” DeRose feels the real fun in working at Pixar is figuring out how to use math and science to resolve problems.

Porter, recalled how in working on surface appearances for “Toy Story,” he came to realize that the bumpiness on Mr. Potato Head was “basic sine and cosine functions that you learn in 11th grade.” He exclaimed, “It’s delightful to me to think here I was in a job in 1992 that people couldn’t even conceive of back in the mid-sixties that was completely relevant to what I was learning in 11th grade.” He was also sure that high school math and physics would eventually be used for “some job that you or I can’t conceive of now.”

For Porter, “Toy Story” remains his sentimental favorite Pixar movie. DeRose’s favorite  Pixar film is “The Incredibles” and his favorite character is Bob. “I’m a real fan of James Bond movies and it kind of plays like James Bond and I kind of sympathize with Bob being a middle-aged dad.”

If you can’t make it to this exhibit, or if you find your curiosity piqued, Porter and DeRose both recommended another resource: Khan Academy. Pixar and the academy created Pixar in a Box, a series of lessons on various aspects of computer animation. DeRose said it’s about “18 hours of learning that helps kids make that connection between how you make digital films and what that science content is.”

“The Science Behind Pixar” is a ticketed event at the California Science Center until April 9, 2017. For more information about the exhibit visit The Science Behind Pixar” will be on tour for ten years. St. Paul’s Science Museum of Minnesota is the next scheduled stop, opening on May 27, 2017 and closing on Sept. 4, 2017.