STRATFORD-UPON-AVON, England — Picture this: It’s the first act of “The Tempest,” and the shipwrecked conjurer Prospero is reminding the spirit Ariel of his miserable past — 12 years imprisoned by a witch inside a “cloven pine.” Theatergoers see two costumed actors, as always, but also, rising high above them, a towering, gnarled tree, within which writhes a 17-foot avatar of Ariel, moaning in recollected agony.

An hour or so later, Ariel, carrying out a mission at Prospero’s behest, morphs into a harpy — a ravenous monster with a woman’s face and breasts and a vulture’s talons and wings — soaring intangibly but menacingly above the stage in a pixelated projection that traces the movements and facial expressions of an actor at stage left.

Here, in the birthplace of Shakespeare, theater artists and technologists are trying to reimagine stagecraft for the digital age.

Experimenting with one of Shakespeare’s greatest — and final — plays, the Royal Shakespeare Company, working with Intel and a London-based production company called the Imaginarium, has mounted a “Tempest” in which Ariel’s physical transformations are made visible with what the collaborators say is the most elaborate use of motion capture ever attempted in live theater.