Visual Effects: Activity 2

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Physical Effects

Physical effects, also known as practical, special or mechanical effects, are performed in front of the camera during principal photography. They include weather effects, water effects and pyrotechnics. Stunts, bullet hits, explosions and collapsing buildings are also considered physical effects.

Rather than rely on the weather to perform as needed, filmmakers look to physical effects to generate such atmospheric events as rain, fog, snow and wind. Sprinklers with various kinds of nozzles produce cinematic rain, which may be heated to keep the actors comfortable. Sometimes, as in the 1952 film Singing in the Rain, water is mixed with paint or with milk to help it show up on screen. Scenes that take place in the water or on rough seas are usually filmed in a studio tank with miniature ships and other vessels. In the 1997 film Titanic, miniatures in a tank represented the sinking ocean liner in some scenes.

Winds ranging from light breezes to hurricanes are created by wind machines, that is, fans of different sizes and powers. Small fans ruffle the actors’ hair and clothes, while a Boeing 707 jet engine drove the tornados in the film Twister (1996). To make wind visible to the camera, lightweight particles such as dust or leaves may be scattered in its path.

Smoke “bombs,” dry ice, pressurized air, and smoke machines using heated oil produce smoke effects. Smoke and lighting effects can also give an illusion of underwater conditions, a technique called “dry for wet.” Dry ice simulates fog and will sometimes be held, carefully wrapped in protective layers, in an actor’s mouth to vaporize his or her breath in cold weather scenes.

Traditionally, salt was substituted for snow in winter scenes, but because it is so harmful to the environment, other alternatives were developed. A combination of white sand, chalk and crystals was tried. Plastics, foams, painted glass, liquid paraffin and potato starch, and falling ash were also found to be effective. Ripped pieces of paper, which move almost like real snow, are a common solution. Several different substances, depending on the needs of a scene, may be used at the same time. New materials that melt on contact like real snow may be used in closeup shots. Today, computer graphics (CG) are often used to paint backgrounds snowy white, while physical snow effects are used in the foreground.

The term “animatronics” was coined in the 1960s to describe three-dimensional mechanical figures developed by Disney engineers for attractions at Disneyland. The earliest mechanical creatures in film, however, date back to the silent era. In 1924, a 60-foot mechanical dragon controlled by 17 technicians was created for the German film Die Nibelungen. Kong’s giant head is another early example of a manipulated puppet.

Animatronics are powered by pumps, motors, hydraulics, computers or other electronic or mechanical means and may be preprogrammed or remotely controlled. Large animatronics may be controlled by many puppeteers, or operators, each responsible for a specific part of the creature. Animatronics include totally mechanical creatures like Yoda in The Empire Strikes Back and mechanical masks that enable an actor to control a character’s facial expressions.

When animatronics are combined with digital animation, as they are in the Jurassic Park series, the more realistic-appearing animatronics are used in the closer shots, while digital animations are seen in the background. Some filmmakers prefer animatronics to CG because it is easier for actors to perform believably when they can interact with an actual entity rather than with a creature that will not appear until post-production.

Special effects makeup is any three-dimensional makeup process including animatronics and prosthetics. Prosthetic makeup—false limbs and features or other large pieces that are attached to actors—are another way to construct monsters, animals and other creatures. The mermaid’s tail in Splash, for example, was a prosthetic made from flexible transparent urethane, dyed and painted to look like red fish scales. For the scene in the film Alien when the alien bursts through a crew member’s chest, a fiberglass chest piece and blood-squirting tubes were used. A puppet operated with wires depicted the escaping creature. To portray the creature in a later scene, a very tall, thin actor wore a costume composed of layers of latex and a head with mechanical jaws.

Physical effects are often quite dangerous both for stunt performers and for the technicians who operate them. Working with stunt coordinators, the physical effects crew devises ways to make stunts as safe as possible. For example, breakaway glass and furniture let a stunt performer smash through a window or be hit by a chair without injury. Good editing also makes stunts safer. In a scene of a man jumping from a burning ship, for instance, the stunt man vaults from a trampoline into the water. Viewers don’t see the trampoline, however, because the editor cuts to the face of a horrified onlooker.

Like all other physical effects, fires must be safe and containable. Often an accelerant is used on part of an otherwise fireproof set to prevent the fire from burning out of control. Devices called flame bars, metal bars of different sizes that burn propane gas, are used behind and in front of objects that are supposed to be on fire. Fireproof boxes filled with smoke and lit with bright lights can be placed inside buildings to make it appear that they are burning.

Explosions, whether small or large, are the domain of physical effects artists. Because blanks do not leave a significant mark when they contact their target, the physical effects crew sets off small explosions to register their impact. (Real bullets, fired by sharpshooters, were used in early films, but this practice was ended by the Screen Actors Guild in the late 1930s.) To show bullet hits on performers, the crew either bursts small capsules filled with fake blood, or places a low-powered explosive against a metal plate next to the performer’s body.

Every explosion is carefully planned to look exactly as the director wishes and to be accomplished as safely as possible. Buildings or vehicles intended for destruction are first weakened, so that a very small amount of explosive will blow them apart. Miniatures are often blown up for practical and safety reasons. Big explosions are usually filmed at a faster-than-normal rate so they will last longer on screen when played back.

Discuss different physical effects with your students. Then show them one or more scenes from a film of your choice. Some suggestions are The Birds, Earthquake, Alien, Blade Runner, Fantastic Voyage, Ghostbusters, Indiana Jones and the Temple of Doom,The Adventures of Baron Munchausen, Jurassic Park, Titanic, or Superman. Ask them to try to figure out which of the physical effects you discussed might have been used in the scene(s). Have them suggest reasons why a director might choose to use physical effects rather than computer-generated effects.

Supplemental Activity

A storyboard is a sequential series of illustrations showing the key actions called for by the script. It helps filmmakers work out composition, camera angles, and action, and can also point out flaws in the script. Some filmmakers, like Steven Spielberg, use a process called pre-visualization, which is essentially a computer-animated storyboard. Pick a scene from a movie or a book that would use physical effects. Have your students make a storyboard of the scene showing how the effects might be put into the film. Discuss the ways the editor and cinematographer could help the effects seem most believable.

Visual Effects: Seeing is Believing

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Complete Visual Effects Activities Guide (PDF)

Activity 1: Visual Effects Beginnings
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Activity 2: Physical Effects
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Activity 3: Computer-Generated Effects
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Activity 4: Visual Effects in Non-Effects Movies
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Bonus Material Related to the 79th Annual Academy Awards Poster
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