A.I. Meets Animation

Image Engine innovates multiple techniques to create the intelligent robotic star of director Neill Blomkamp’s Chappie. By Bill Desowitz.

In his most-recent sci-fi actioner, Chappie, South African director Neill Blomkamp returns to his District 9 roots in Johannesburg to focus on a broken police robot who becomes sentient thanks to an ambitious inventor, played by Dev Patel.

As always with Blomkamp, there’s a political subtext. In this case, it’s about humanizing humanity, which has become too violent and oppressive.

The movie was adapted from the director’s 2003 short about an autonomous robotics company that has replaced law enforcement in South Africa. Blomkamp thought it would be cool to link the design of Chappie back to the short. And because he wanted the robot to be anthropomorphic, he envisioned it designed in a cost-effective way for law enforcement so it could fire weapons, go through doors and drive cars. However, the ’ bots — or “scouts,” as they are called — have to be taken seriously by criminals and at the same time be empathetic to viewers.

Thus, Chappie posed an interesting animation challenge for Image Engine.

Although they considered performancecapture on Blomkamp’s favorite actor, Sharlto Copley, who voices Chappie, they decided that it was too expensive and time consuming to suit the director’s filmmaking needs. Instead, the actor donned a gray suit on set and the animators hand-animated on top of him, in what Image Engine VFX supervisor Chris Harvey calls “the poor man’s” mo-cap.

“He is in all the plate photography with the other actors, then we removed him and replaced him with the digital Chappie,” Harvey says. “It was his being on set and acting like any actor would, in a gray suit, and then we took that back to Image Engine and the animators basically just had him in the background and fully hand key-framed on top of it to match his performance. The other thing we did was we were able to use it as an incredibly accurate lighting reference by sticking the same gray material in the computer as a calibration to make sure that the lighting we put on our digital Chappie really matched what was on set.”

An Early Start Image Engine got involved in the build of Chappie in collaboration with Weta Workshop six to eight months before the shoot, which is pretty unusual because the practical build usually drives the digital build.

“In this case, it was a little bit different,” Harvey says. “Neill had some concept art for Chappie, but then he gave that to us and we fleshed that out in three dimensions, well before Weta had to build the practical model. The reason we did this was it allowed Neill to play with it digitally and to make quick changes, but also one of the important things was that the movement felt like Sharlto’s performance. We needed to make sure that Chappie’s ‘physiology’ could line up very well to Sharlto’s. So body proportions, joint placement made it a lot easier to mimic his performance and translate well onto the robot.

“In addition, we spent a lot of time working out the physical mechanics of Chappie. He’s built without any cheats because we worried about pulling the audience out of his believability. And so Neill didn’t want to use ball joints. He wanted to use known, mechanical systems that were all very familiar, so all of his joints are complex, single axis, rotational; and so we built a complicated hierarchy of jointing and rigging for his body. That was somewhat automated so that everything would properly move and bend by the animators. When we did finally get Sharlto’s performance, we would properly match that.”

Apparently, if you look at Chappie closely and study Copley, he moves like the actor, but it’s still a natural, mechanical movement. It became a creative balancing act. On the other hand, the oth- er scout ’bots and the gigantic Moose ’bot have much more rigid movements because they are not A. I.-driven like Chappie.

In terms of the toolset, Image Engine used Maya for animation, ZBrush for modeling, Nuke for compositing and Houdini for VFX along with a lot of proprietary look-development and rigging software.

Going Gangster A key moment is called the “real gangster” scene, in which Chappie mimics the cool strut of a thug ( Ninja Visser from the South African rap group Die Antwoord), who takes possession of Chappie and uses him to commit heists. “It was a really fun scene to do because Chappie goes through quite a large evolution in the film,” Harvey says. “He starts out as a police robot, but then he wakes up like a toddler and becomes alive. He’s young, he’s curious and he doesn’t understand the world yet. He’s jumpy about things. But as he progresses, he learns. By the time we get to the gangster scene, he wants to fit in with his family. He wants to be one of the gang. And Ninja teaches him how to be cool, and so this becomes a transitional scene, where Chappie starts to pick up his gangster walk and some of the arm movements and head twitches.

“We also got a great body performance from Sharlto. He did a number of things to help and asked to put on these shorts and we stitched them on so he could get that gangster gait. He really understood it was going to be a team effort and even visited the facility and talked with the animators, so he was very aware of the work that didn’t come until afterward. He was also asking if his performance was too much or too little. We also enhanced some of Sharlto’s head performance, exaggerating twitches and other movements to get a better emotional read.” Bill Desowitz is owner of Immersed in Movies (www.billdesowitz.com), a regular contributor to Animation Scoop at Indiewire and author of James Bond Unmasked (www.jamesbondunmasked.com).