DRAWINGS and sketches by movie directors Federico Fellini, Alfred Hitchcock, Martin Scorsese and Tim Burton will be displayed at the Motion Picture Academy from September 10 through October 17. Ten directors in all will be represented in the show, juxtaposing each director's original concepts on paper of actual scenes they later created on film. The exhibition includes the directors' pre-production drawings, production stills of the same images and film clips on video showing the completed scenes. Universal Pictures has bought film rights to author James Dickey's still-unpublished novel To the White Sea for producer Richard Roth. The property is Dickey's third novel and deals with a World War II American Air Force gunner whose plane is shot down over Tokyo during a bombing raid. It will be published next month. Dickey's best known novel was his first, Deliverance , which became the John Boorman movie starring Burt Reynolds and Jon Voight. CBS will produce a Thanksgiving-themed reunion special of The Waltons , with Lee Rich producing the two-hour film. The Waltons Thanksgiving is scheduled for November 30th and will include almost all of the surviving cast members of the highly-rated family-oriented series that ran from 1972 to 1981. The series starred Ralph Waite, Michael Learned and Richard Thomas and has played consistently in syndication since leaving network primetime.