HERE AND THERE

THERE ARE TWO VERSIONS OF A BMW factory in the medieval town of Regensburg, Germany. One is a physical plant that cranks out hundreds of thousands of cars a year. The other is a virtual 3-D replica, accessed by screen or VR headset, in which every surface and every bit of machinery looks exactly the same as in real life. Soon, whatever is happening in the physical factory will be reflected inside the virtual one in real time: frames being dipped in paint; doors being sealed onto hinges; avatars of workers carrying machinery to its next destination.

The latter factory is an example of a “digital twin”: an exact digital re-creation of an object or environment. The concept might at first seem like sci-fi babble, or even a frivolous experiment: Why would you spend