In a screenplay, all the actions, descriptions and conversations of all the character of a film are written out according to a prescribed format. Intangible aspects of character like their thoughts are not normally included. The document is the principal guide for the Producer, Director and the entire film crew. A finished screenplay draft is normally completed before all productions commence, though the script is sometimes altered during production, for example when an actor has trouble with some dialogue or characterization or gaps in logic in the action.