Recent leaps in postproduction have created a need for sound designers to respond to an increasingly fluid workflow. Whole sequences now come from visual effects developers, with a large number of internal timing and content changes that don't register as "picture changes" to anyone but the sound editor. As lead sound designers shape tracks farther and farther in advance of the formal re-recording stage, the challenge is to give re-recording mixers more freedom to navigate the upstream decisions made by sound editors.