Most films require some special effects. This term normally refers to illusions created on the film set, rather than in postproduction. (Digital effects and other effects created off-set are discussed in depth below.) The department is headed by the special effects supervisor, and its members may include such crew as a pyrotechnician, who is an expert in creating fires and explosions, a model maker, a puppeteer, and a projectionist, who operates the equipment needed for back projection. The special effects crew normally works closely with other departments, such as makeup or stunts, so there may be no clear division between them.
Some other crew members commonly employed include runners or production assistants, security guards, a maintenance engineer, a health and safety adviser, and a unit nurse. Additional services are required for location work. The transportation captain organizes the movement of actors, crew members, and equipment between sets and locations. A transport coordinator may also be employed to supervise the availability of drivers and vehicles. Catering, a crucial service during a shoot is provided by a company or group of individuals who supply the main meals to cast and crew. The craft service maintains the availability of drinks and snacks throughout the day.