When director Joachim Rønning came on board “Tron: Ares,” the third film in the Disney sci-fi series that began in 1982 with “Tron,” he knew there was one set piece that absolutely had to deliver.

When it comes to the art of visual effects, there's before Tron and after Tron. The original 1982 Disney movie made history as one of the first Hollywood productions to extensively employ then-cutting ...