The robots of Christopher Nolan's Interstellar, the walking boxes TARS and CASE, were two of my favorite characters from last year's science fiction film. Having not paid much attention to the making of Interstellar, I assumed that they were purely computer-generated and not puppeteer-controlled practical effects.

In a behind the scenes video for Interstellar, we get a look at how TARS and CASE were designed and controlled, and when they were replaced (or enhanced) by CGI. Christopher Nolan and other members of the film crew talk about the "minimalist approach" to designing those military robots, which they describe as "articulated planks." Making those big metal boxes walk wasn't easy according to TARS voice actor and puppeteer Bill Irwin, as versions of the robots weighed up to 200 pounds.

For our thoughts on Interstellar, read Polygon's review.