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The movie was inspired by writer and co-star Brian Doyle-Murray's memories working as a caddy at Indian Hill Club in Winnetka, Illinois. His brother Bill Murray and director Harold Ramis also worked as caddies when they were teenagers. Many of the characters in the film were based on characters they had encountered through their various experiences at the club, including a young woman upon whom the Maggie character is based and the Haverkampfs, a doddery old couple, John & Ilma, longtime members of the club, who can barely hit the ball out of their shadows ("That's a peach, hon"). The now legendary scene involving a Baby Ruth candy bar being thrown into the swimming pool was based on a real-life incident at Brian Doyle-Murray's high school.[2]
Initially, Ted Knight's and Scott Colomby's characters were the central characters of the movie. However, the improvisational atmosphere surrounding the other cast members (specifically Dangerfield, Chase, and Murray) led to Dangerfield's, Chase's and Murray's roles expansion from cameos to starring roles, much to the annoyance of Knight and Colomby. Additionally, Knight, who was regarded as a genuinely nice person in real life, became fed up with the constant improvisation.[3]
The pool scene was filmed at Plantation Country Club in Plantation, Florida. The pool had not been used for several years prior to filming and was considerably revamped and then filled for the production.[citation needed]
The film was shot over 11 weeks during the autumn of 1979.
Golf scenes were filmed at the Rolling Hills Golf Club in Davie, Florida. The explosions that take place during the climax of the film were reported at the nearby Fort Lauderdale airport by an incoming pilot, who suspected a plane had crashed.[2]
The famous scene that begins when Ty Webb's golf ball crashes into Carl Spackler's ramshackle house was not in the original script. It was added by director Harold Ramis after realizing that two of his biggest stars, Chevy Chase and Bill Murray (who did not get along due to a feud dating back to their days on Saturday Night Live), did not have a scene together. The three met for lunch and wrote the scene together. Although the scene has nothing to do with the plot, it is widely regarded as the funniest in the movie. This is the only time that Chase and Murray have appeared in a movie together.[4]
Bill Murray's famous "Cinderella story" scene was improvised based on two lines of stage direction. Ramis basically gave him direction to act as a kid announcing his own imaginary golf moment. Murray just took it from there. The flowers were his idea.[4]
In interviews, Cindy Morgan stated that the scene she shared with Chevy Chase, in which he pours massage oil on her, was completely improvised, and her reaction to Chase dousing her back with the massage oil, where she exclaimed "You're crazy!", was genuine.[3] Due to the fact she is legally blind without glasses or contacts, as well as afraid of heights, there was concern about the scene where she had to dive into the pool. Morgan climbed the ladder, but the flawless dive was executed by a professional diver.[5]
The gopher sequences were written and filmed after most of the movie was shot. Originally, director Harold Ramis wanted to cast a live animal to play the gopher. When that did not work out, the animatronic gopher (credited as "Chuck Rodent") and its tunnels were built by John Dykstra.[4] The gopher sounds were the same sounds used by Flipper the dolphin in the 60's television show of the same name. This was after principal cinematography had been completed and used higher quality film stock in an indoor soundstage resulting in the higher picture quality of these scenes still evident even on the current DVD.[3]