Locomotion | TARS is basically a robotic Kit Kat bar. His four “fingers” can execute a two-legged gait, a “crutch walk,” a scissor kick, and a full-on four-legged gallop.
Appendages | When the bot articulates, his fingers can subdivide into smaller, identical appendages. In the movie, we see three subdivisions, but the CG team prepped up to five. By that point, the extremities were like toothpicks.
Personality | You could describe TARS as the film’s comic relief. In collaboration with Nolan, actor Bill Irwin decided to play the character ”somewhere between a marine company commander and a gym teacher.”
Special Effects | F/x coordinator Scott Fisher, whose team built the eight robots used for production, estimates that 80 percent of the bot footage in the final cut was shot in-camera, no CG required. “When things fold out in a way that’s impossible,” he says, “your eye catches it and you know it’s fake.” CG was reserved for acts of extraordinary robotics, like when a bot named CASE turns into a massive asterisk and tumbles through water.
Materials | Weighing almost 200 pounds, TARS is an aluminum skeleton skinned in stainless steel. It took six weeks and about $20,000 to build. But a real-life TARS? “It’d definitely cost more,” Fisher says. Accounting, ya know, for the whole AI thing.
Performance | Tars’s dialog wasn’t dubbed after the fact—Irwin recorded it live. But that’s not all: He also operated the hydraulics that controlled the heavy machines. (Irwin is a few inches taller than TARS, which meant erasing his forehead in postproduction.) During filming in Iceland, Irwin had to work in thigh-deep water, and the robots’ metal corroded so badly that two models had to be disassembled and rebuilt.
Face | TARS isn’t supposed to have a face, but he does have screens. The cast couldn’t help themselves. “It was a natural point of focus for them,” visual f/x supervisor Paul Franklin says. “Despite our attempts to erase all traces of humanoid form from it, people look for faces.”