Moments later, McKellen was in a conference room, where he surveilled a tray of snacks. Selecting a bag of potato chips, he enthusiastically read aloud the word “Classic” from the package and commenced gobbling. “An Ark” was so lifelike that he had instinctively reached out his hand when one of the characters had encouraged the audience to touch her; still, he said,“it is with a sigh of relief that I say that this medium is not going to overtake the theatre as an art form.” He had tangled with technology in the early days of filming the C.G.I.-heavy “Lord of the Rings,” in 1999 and 2000: in one scene, tasked with interacting with a group of other actors represented only by their photographs, McKellen had mumbled, “This isn’t why I became an actor,” and then he wrote a letter to the film’s director, Peter Jackson, offering to quit. “I couldn’t do that scene,” he said. “I don’t think any actor could. So we found some other way to do it.”