On a warm afternoon last fall, Steven Caron, a technical artist at the video-game company Quixel, stood at the edge of a redwood grove in the Oakland Hills. “Cross your eyes, kind of blur your eyes, and get a sense for what’s here,” he instructed. There was a circle of trees, some logs, and a wooden fence; two tepee-like structures, made of sticks, slumped invitingly. Quixel creates and sells digital assets—the objects, textures, and landscapes that compose the scenery and sensuous elements of v...