VFX-An Overview

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  • Visual effects Visual effects (commonly shortened to Visual FX or VFX) are the various processes by which imagery is created and/or manipulated outside the context of a live action shot. Visual effects involve the integration of live-action footage and computer generated imagery to create environments which look realistic, but would be dangerous, expensive, impractical, or simply impossible to capture on film. Visual effects using computer generated imagery has recently become accessible to the independent filmmaker with the introduction of affordable and user friendly animation and compositing software. Visual effects are often integral to a movie's story and appeal. Although most visual effects work is completed during post-production, it usually must be carefully planned and choreographed in pre-production and production. Visual effects primarily executed in Post-Production, with the use of multiple tools and technologies such as graphic design, modeling, animation and similar software, while special effects are made on set, such as explosions, car chases and so on. A visual effects supervisor is usually involved with the production from an early stage to work closely with production and the film's director design, guide and lead the teams required to achieve the desired effects. Visual effects may be divided into at least four categories:

    Models: miniature sets and models, animatronics, stop motion animation. Matte paintings and stills: digital or traditional paintings or photographs which serve as

    background plates for keyed or rotoscoped elements. Live-action effects: keying actors or models through blue screening and green

    screening. Digital animation: modeling, computer graphics lighting, texturing, rigging, animating,

    and rendering computer-generated 3D characters, particle effects, digital sets, backgrounds.

    Digital effects (commonly shortened to digital FX or FX) are the various processes by which imagery is created and/or manipulated with or from photographic assets. Digital effects often involve the integration of still photography and computer generated imagery (CGI) in order to create environments which look realistic, but would be dangerous, costly, or simply impossible to capture in camera. FX is usually associated with the still photography world in contrast to visual effects which is associated with motion film production.

  • A miniature effect is a special effect created for motion pictures and television programs using scale models. A scale model is a physical model, a representation or copy of an object that is larger or smaller than the actual size of the object, which seeks to maintain the relative proportions (the scale factor) of the physical size of the original object. Very often the scale model is used as a guide to making the object in full size. Scale models are built or collected for many reasons. Scale models are often combined with high speed photography or matte shots to make gravitational and other effects appear convincing to the viewer. The use of miniatures has largely been superseded by Computer-generated imagery in the contemporary cinema. Where a miniature appears in the foreground of a shot, this is often very close to the camera lens for example when matte painted backgrounds are used. Since the exposure is set to the object being filmed so the actors appear well lit, the miniature must be over-lit in order to balance the exposure and eliminate any depth of field differences that would otherwise be visible. This foreground miniature usage is referred to as forced perspective. Another form of miniature effect uses stop motion animation. Use of scale models in the creation of visual effects by the entertainment industry dates back to the earliest days of cinema. Models and miniatures are copies of people, animals, buildings, settings and objects. Miniatures or models are used to represent things that do not really exist, or that are too expensive or difficult to film in reality, such as explosions, floods or fires. Special Effects (often abbreviated as SFX, SPFX, or simply FX). The illusions or tricks of the eye used in the film, television, theatre, video game, and simulator industries to simulate the imagined events in a story or virtual world are traditionally called special effects. Special effects are traditionally divided into the categories of Optical Effects and Mechanical Effects. With the emergence of Digital Film-Making Tools a greater distinction between Special Effects and Visual Effects has been recognized, with "visual effects" referring to digital post-production and "special effects" referring to on-set mechanical effects and in-camera optical effects.

  • Optical effects (also called photographic effects), are techniques in which images or film frames are created photographically, either "in-camera" using multiple exposure, mattes, or the Schfftan process, or in post-production processes using an optical printer. An optical effect might be used to place actors or sets against a different background. Mechanical effects (also called practical or physical effects) are usually accomplished during the live-action shooting. This includes the use of Mechanized Props, Scenery, Scale Models, Animatronics, Pyrotechnics and Atmospheric Effects: creating physical wind, rain, fog, snow, clouds, etc. Making a car appear to drive by itself and blowing up a building are examples of mechanical effects. Mechanical effects are often incorporated into set design and makeup. For example, a set may be built with break-away doors or walls to enhance a fight scene, or prosthetic makeup can be used to make an actor look like a non-human creature.

    Early development

    In 1856, Oscar Rejlander created the world's first "Trick Photograph" by combining different sections of 30 negatives into a single image.

    In 1895, Alfred Clark created what is commonly accepted as the first-ever motion picture special effect.

    While filming a reenactment of the beheading of Mary, Queen of Scots, Clark instructed an actor to step up to the block in Mary's costume. As the executioner brought the axe above his head, Clarke stopped the camera, had the entire actors freeze, and had the person playing Mary step off the set. He placed a Mary dummy in the actor's place, restarted filming, and allowed the executioner to bring the axe down, severing the dummy's head. "Such techniques would remain at the heart of special effects production for the next century."

    This was not only the first use of trickery in the cinema; it was the first type of photographic trickery only possible in a motion picture, i.e. the "Stop Trick".

    In 1896, French magician Georges Mlis accidentally discovered the same "Stop Trick"

  • According to Melies, his camera jammed while filming a street scene in Paris. When he screened the film, he found that the "Stop Trick had caused a truck to turn into a hearse, pedestrians to change direction, and men turn into women.

    Melies, the stage manager at the Theatre Robert-Houdin, was inspired to develop a series of more than 500 short films, between 1914, in the process developing or inventing such techniques as multiple exposures, time-lapse photography, dissolves, and hand painted colour.

    In Analogue photography and cinematography, Multiple Exposures is a technique in which the camera shutter is opened more than once to expose the film multiple times, usually to different images. The resulting image contains the subsequent image/s superimposed over the original. The technique is sometimes used as an artistic visual effect and can be used to create ghostly images or to add people and objects to a scene that were not originally there.

    Time-lapse photography is a technique whereby the frequency at which film frames are captured is much lower than that used to view the sequence. When played at normal speed, time appears to be moving faster and thus lapsing.

    For example, an image of a scene may be captured once every second, then played back at 30 frames per second. The result is an apparent 30-times speed increase. Time-lapse photography can be considered the opposite of High Speed Photography or Slow Motion.

    Some classic subjects of Time-Lapse Photography include:

    cloudscapes and celestial motion plants growing and flowers opening fruit rotting evolution of a construction project people in the city

  • Mattes are used in photography and special effects filmmaking to combine two or more image elements into a single, final image. Usually, mattes are used to combine a foreground image (such as actors on a set, or a spaceship) with a background image (a scenic vista, a field of stars and planets). In this case, the matte is the background painting. In film and stage, mattes can be physically huge sections of painted canvas, portraying large scenic expanses of landscapes.

    In film, the principle of a matte requires masking certain areas of the film emulsion to selectively control which areas are exposed. However, many complex special-effects scenes have included dozens of discrete image elements, requiring very complex use of mattes, and layering mattes on top of one another.

    For an example of a simple Matte, we may wish to depict a group of actors in front of a store, with a massive city and sky visible above the store's roof.

    We would have two imagesthe actors on the set, and the image of the cityto combine onto a third.

    This would require two masks/mattes. One would mask everything above the store's roof, and the other would mask everything below it.

    By using these masks/mattes when copying these images onto the third, we can combine the images without creating ghostly double-exposures. In film, this is an example of a Static Matte, where the shape of th