'Rogue One: A Star Wars Story': Inside the Creation of the Droid K-2SO

— -- The scene-stealing droid K-2SO in "Rogue One" may be from a galaxy far, far away, but his origin story begins inside the San Francisco headquarters of visual effects powerhouse Industrial Light & Magic, or ILM.

Creating K-2SO -- a completely digital character based on a real-life performance by actor Alan Tudyk was the work of hundreds of concept artists, animators and digital artists at ILM, including Landis Fields.

“It's a huge team,” said Fields, who also helped build droid BB-8 for “Star Wars Episode VII: The Force Awakens.” “For Kaytoo, they knew that they wanted to have the footprint look like something that wasn't just a man in a suit."

Fields built many of K-2SO’s complex moving parts, including wrist, knee and elbow joints in a 3-D computer program. From there, other artists digitally assembled, textured and painted the 3-D model to transform it into the final movie version.

Fields said part of K-2SO’s design was inspired by a Disney theme park ride -- but not just any ride.

“Star Tours has this motion base that basically allows the ride to move and simulate the feeling of gravity. So, we wanted to pay homage to that,” Fields said. “Everybody liked it. So, after the motion tests, we integrated it into the shoulders and the hips, actually.”

While shooting “Rogue One: A Star Wars Story," Tudyk was on the set playing K-2SO so that filmmakers could capture realistic interactions with fellow cast members, including Felicity Jones and Diego Luna.

“If you do it later, it's not going to make any sense. It's not going to gel with the rest of the actors,” Tudyk said.

As cameras rolled, Tudyk wore a special motion capture suit along with stilts that brought him to Kaytoo’s proper height of seven feet.

The motion capture system allowed Tudyk’s performance to be recorded on-set, and later applied to the K-2SO model. Digital artists then erased Tudyk from the original shot and replaced him with his droid alter-ego.

“The whole idea is to give the actor the best opportunity to do their work,” said "Rogue One" animation supervisor Hal Hickel. “And the best place for them to do that is on set with the other actors, interacting with them, that's where the magic happens.”

Fields, part of an ILM team that just scored an outstanding virtual cinematography nomination from the Visual Effects Society for “Doctor Strange,” said seeing K-2SO on the big screen is surreal.

“You kind of now know the magic behind it,” Fields said. “So, that's a lot of fun -- just knowing what happens behind the curtain.”

Lucasfilm and Industrial Light & Magic are part of ABC News' parent company, Disney.