Creating a kids movie poses unique challenges: How scary should it be? How do you make it simple enough for kids but compelling enough so that adults don’t spend 90 minutes wishing for the sweet release of death? And how many butt jokes is the right number of butt jokes?

“It’s not like we have a formula,” says Alessandro Carloni, co-director of “Kung Fu Panda 3,” out Friday.

Yet co-director Jennifer Yuh says there are some basic ingredients: “In all the ‘Kung Fu Panda’ movies, we come back to three things: emotion, comedy and action.” Also in the mix are Carloni and Yuh themselves. The two have been involved in all three films at various levels.

“If there’s a lot of emotion and no comedy or action, people get restless because, while emotion is great, it feels preachy,” says Yuh, who also directed 2011’s “Kung Fu Panda 2.” “Too much comedy and no emotion or action, then people get restless because ‘why are we watching this?’ If there’s too much action and none of the other things, the kids get scared.”

Getting the action right is especially important to Yuh, a devoted fan of martial arts films. “The whole reason I signed on to the first one was so I could work on action scenes,” she says. “[They] are so complicated, and you have so many characters interacting with one another.”

In a “Kung Fu Panda” movie, you might have a snake, a tiger, a bird, a grasshopper and Po, the titular panda voiced by Jack Black, all fighting at the same time.
Advances in animation technology since the first “Kung Fu Panda” came out in 2008 have made things easier, Carloni says. Plus, animators today can add emotional shading they couldn’t before.

“For the original movie, we were basically inputting data,” Carloni says. “You’d see the artists saying ‘oh, he has to smile’ and then typing. Now they use a touch screen with a pen; with Po, you can basically just touch his mouth and get the exact right smile. An artist is able to truly interact with characters in a much more intuitive way.”

The final element of the films is the human one. “When we storyboard the movie, we record our own voices and our crew’s voices, just to get the rhythm of it,” Carloni says. “But you don’t buy it. You don’t feel the emotion. Then Jack Black comes in and you first think ‘oh, he’s a clown.’ But then he makes you feel all these things.”

More interviews from Kristen Page-Kirby: