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.via Gizmodo.
If you've seen Interstellar, then you know that the best characters are the wise-cracking robots. Unassumingly boxy and faceless, they somehow end up stealing the show. Wired has a fascinating behind-the-scenes look on bringing the robots to life—largely without the help of CGI. Minor spoilers ahead. Interstellar's F/X coordinator, Scott Fischer, reveals that 80 percent of the robot footage in the movie was real. The few exceptions are the action sequences, such as when the robot CASE reveals itself not to be not just a clumsy rectangle, transforming into a nimble jack that tumbles through the water. The team built a total of eight robots for the shoot. The robot TARS, one of the film's main AI characters, weighed 200 pounds and cost $20,000. For Bill Irwin, the voice behind the robot TARS, playing a robot was no piece of cake either. Wired explains: