Lucas announced in January that he was engaged to Mellody Hobson, a Chicago money manager, and he has been spending much of his time in her hometown. Even so, he’s attended story meetings for the new film, adjudicating the physical laws and attributes of the Star Wars universe. “I mostly say, ‘You can’t do this. You can do that,’ ” Lucas says. “You know, ‘The cars don’t have wheels. They fly with antigravity.’ There’s a million little pieces. Or I can say, ‘He doesn’t have the power to do that, or he has to do this.’ I know all that stuff.”