MYRTLE BEACH, S.C. _ When Robert Siegel planned to shoot a movie set in a beach resort town, he started in Ocean City, Md., and headed south, scouting each beach along the way.
When he reached Myrtle Beach, a walk on Ocean Boulevard convinced him he had found the right place.
``I was following these three young women,'' he said, ``and I was watching the social ritual as each car would go by and flirt a little bit. And I said `Oh, my God, this is clearly where I want to shoot this film. ... To me, Myrtle Beach is like the quintessential beach town.''
The resulting film, ``Swimming,'' opened Friday. It is the latest in a growing list of film and …