What it takes to be a reference actor for animation

• Reference footage of stunt performers helped to create realistic animated fight scenes in "Avatar: The Last Airbender" and "The Legend of Korra."
• The primary martial arts consultant for these shows was Sifu Kisu, a martial arts master who served as both a fight choreographer and stunt performer.
• The martial artists were filmed at specific camera angles to make it easier for storyboard artists and animators to draw their movements accurately.
• Giancarlo Volpe, a director of several "Avatar" episodes, said that having the reference footage was a net positive because it reduced the time that storyboard artists had to spend drawing action and increased the authenticity of the characters' movements.

Following is a full transcript of the video.

[grunting]

[air whooshing]

Narrator: These behind-the-scene clips are what's known as reference footage. Reference footage is used in animation all the time to make sure animated characters' movements, like walking and jumping, are realistic.

Probably the most difficult scenes to animate are fight scenes, like the extremely complex head-to-heads in "Avatar: The Last Airbender" and "The Legend of Korra."

Animator: Instead of just going on the ground on his butt, he actually drops down, and he's like,

[blows]

on his finger. There's, like, air. You know, there's, like, wind.

Narrator: To animate them meant finding someone who could perform and choreograph multiple martial arts styles.

Sifu Kisu: It was fun. I was the only person on the planet with my job for a hot minute.

Narrator: That's Sifu Kisu, a master of martial arts and the fight choreographer and reference actor for "Avatar: The Last Airbender."

Kisu has over 40 years of experience in martial arts and has studied tae kwon do, karate, jujitsu, Northern Shaolin-style kung fu, and more.

Kisu worked on all 61 episodes of "Avatar" and collaborated with a team of martial arts experts on "Korra." In "Avatar," having a choreographer and reference actor was especially important because the four kingdoms used different fighting styles with their own specific movements.

Kisu based each distinct bending style on a different martial art. The fluid movements of waterbending are based on tai chi, the spinning movements of airbending are taken from bagua, the powerful movements of firebending are based on Northern Shaolin-style kung fu, and the sturdy, low-center-of-gravity movements of earthbending are based on hung ga.

The first step in creating these animated fight sequences is storyboarding, when the artists receive a script and draw rough sketches of an entire episode. The descriptions of fight scenes in scripts typically only include the broad strokes of the fight, so the director of the episode will often create the temporary choreography during this initial phase.

Giancarlo Volpe: When we got to the actual fighting, you know, who kicks, who punches, who was the aggressor and all that, oftentimes I do something like this, where it's like, "Aang shoots air," and I'll just do this or something. Do a drawing that looks like that.

Narrator: After storyboarding comes choreography, where Kisu met with the animation team to refine the choreography of the fight scenes. There were usually about five to 10 fight scenes per episode that had to be choreographed. K

isu says that in this first meeting, he would just pitch a series of movements that he thought would represent a certain type of bending. For example, Kisu said that if a firebending technique called for swinging, flaming fists, he would suggest an appropriate movement, such as striking motions from double dagger form kung fu.

Other animated shows have tried to mix magic and martial arts, but Kisu noted that they don't often use martial arts movements when conjuring magic. You can see this when comparing "Avatar: The Last Airbender" to other shows featuring supernatural powers, like some scenes from "Dragon Ball Z."

Kisu: It's like, if I'm holding a stone in my hand like this and it jumps out of my hand and hits the camera, you're going to question that, right? But if I wind up and I make the motion and the antic of throwing that, then that's going to read more to something you can understand, right?

But we thought that that would be important, that it should come from somewhere to go to somewhere. And I think that was one of the big contributing factors to the success of "Avatar: The Last Airbender."

Narrator: After Kisu and the director agreed on the choreography, they filmed the action. Kisu sometimes performed the fight choreography for two or more fighting characters separately.

Animators would later take these shots and combine them into a single fight between characters. After filming, the artists took the footage and used it to add more detail, like specific poses, to their initial storyboards. The time it cost to do the reference filming was recouped by having an extremely accurate model for drawing. Ultimately, this led to a better final product, because the character poses were more accurate.

The storyboard team sent the polished storyboards back to Kisu for review.

Volpe: Then it'd be sort of a back and forth where, like, maybe we come up with a new shot that we never talked about during the first meeting.

Narrator: This process was repeated two to three times until everyone was satisfied with the result. Before sending the finished storyboards off to a team in Korea for the final animation, the director would film one final version of the fight with Kisu with all of the finalized camera angles.

Kisu: If it was going to be a wide angle, we had these bleachers that were in, like, a little makeshift basketball court at Nickelodeon, and guys would crawl up there with the camera and get a down shot. We'd change to a wide angle and make it look like it was really far away.

Like, the fight with Zuko and Azula on the boat dock, where she tried to scratch his face and they had a fire battle, that was done on the front steps at Nickelodeon in front of the SpongeBob statue.

Narrator: Storyboards aren't created for every frame. They're created for every third frame of animation, so the reference footage made it easier for the animators to create the in-between frames that were missing.

While having reference footage is ideal, sometimes it was impossible to capture accurate live-action reference footage, mostly because the characters possess magical powers. Some fights in the show called for a movement that no real human could replicate, like this scene from "Korra."

In these situations, the martial artists would split up the action into several chunks, which would be stitched together in the final animation.

Kisu: In the beginning credits for "Avatar: The Last Airbender," when Zuko would do the big whirlwind kick with the flame and he'd come down and hit the ground, at the time, I was recovering from an injury, and so I couldn't do that kick. We call it a one-legged whirlwind kick. And so I'm literally rolled over someone's back, like, someone bent over, and then I just rolled over that person's back.

The opening credits for "Korra," they show, the airbender does this crazy thing where he kicks this way and lays back that way. I ended up just holding Brian in my arms, which is really funny.

Narrator: It's this lifelike martial arts choreography and attention to detail that make the difference between static fight scenes, like this, and dynamic ones, like this.