Visual Effects and Natural Simulation

Visual Effects and Natural Simulation
The Sci-Fi Blast
If one film could be said to have established a new high-bench mark for special effects, it would be 1968's 2001: A Space Odyssey, directed by Stanley Kubrick, who assembled his own effects team (Douglas Trumbull, Tom Howard, Con Pedersen and Wally Veevers) rather than use an in-house effects unit. In this film, the spaceship miniatures were highly detailed and carefully photographed for a realistic depth of field. The shots of spaceships were combined through hand-drawn rotoscopes and careful motion-control work, ensuring that the elements were precisely combined in the camera – a surprising throwback to the silent era, but with spectacular results. Backgrounds of the African vistas in the "Dawn of Man" sequence were combined with soundstage photography via the then-new front projection technique. Scenes set in zero-gravity environments were staged with hidden wires, mirror shots, and large-scale rotating sets. The finale, a voyage through hallucinogenic scenery, was created by Douglas Trumbull using a new technique termed slit-scan. Even today, the effects scenes remain impressive, realistic, and awe-inspiring.
The 1970s provided two profound changes in the special effects trade. The first was economic: during the industry's recession in the late 1960s and early 1970s, many studios closed down their in-house effects houses. Many technicians became freelancers or founded their own effects companies, sometimes specializing on particular techniques (opticals, animation, etc.).
The second was precipitated by the blockbuster success of two science fiction and fantasy films in 1977. George Lucas's Star Wars ushered in an era of fantasy films with expensive and impressive special-effects. Effects supervisor John Dykstra, A.S.C. and crew developed many improvements in existing effects technology. They developed a computer-controlled camera rig called the "Dykstraflex" that allowed precise repeatability of camera motion, greatly facilitating travelling-matte compositing. Degradation of film images during compositing was minimized by other innovations: the Dykstraflex used VistaVision cameras that photographed widescreen images horizontally along stock, using far more of the film per frame, and thinner-emulsion filmstocks were used in the compositing process. The effects crew assembled by Lucas and Dykstra was dubbed Industrial Light and Magic, and since 1977 has spearheaded most effects innovations.
That same year, Steven Spielberg's film Close Encounters of the Third Kind boasted a finale with impressive special effects by 2001 veteran Douglas Trumbull. In addition to developing his own motion-control system, Trumbull also developed techniques for creating intentional "lens flare" (the shapes created by light reflecting in camera lenses) to provide the film's undefinable shapes of flying saucers.
The success of these films, and others since, has prompted massive studio investment in effects-heavy fantasy films. This has fuelled the establishment of many independent effects houses, a tremendous degree of refinement of existing techniques, and the development of new techniques such as CGI. It has also encouraged within the industry a greater distinction between special effects and visual effects; the latter is used to characterize post-production and optical work, while special effects refers more often to on-set and mechanical effects.
Introducing Computer Generated Imagery (CGI)
A recent and profound innovation in special effects has been the development of computer generated imagery, or CGI, which has changed nearly every aspect of motion picture special effects. Digital compositing allows far more control and creative freedom than optical compositing, and does not degrade the image like analogue (optical) processes. Digital imagery has enabled technicians to create detailed models, matte "paintings," and even fully-realized characters with the malleability of computer software.
The most spectacular use of CGI has been the creation of photographically-realistic images of fantasy creations. Images could be created in a computer using the techniques of animated cartoons or model animation. (In 1993, stop-motion animators working on the realistic dinosaurs of Steven Spielberg's Jurassic Park were retrained in the use of computer input devices.) By 1995, films such as Toy Story underscored that the distinction between live-action films and animated films was no longer clear. Other landmark examples include a moving stained-glass window in Young Sherlock Holmes, a tentacle of water in The Abyss, a 'liquid metal' villain in Terminator 2: Judgment Day, and hordes of armies of fantastic creatures in The Lord of the Rings trilogy.
First thing First
Although most special effects work is completed during post-production, it must be carefully planned and choreographed in pre-production and production. A Visual effects supervisor is usually involved with the production from an early stage to work closely with the Director and all related personnel to achieve the desired effects.
Live special effects
Live special effects are effects that are used in front of a live audience, mostly during sporting events, concerts and corporate shows. Types of effects that are commonly used include a laser lighting, CO2 effects, pyrotechnics, confetti and other atmospheric effects such as bubbles and snow.

Matte Paintings
History
Traditionally, matte paintings were made by artists using paints or pastels on large sheets of glass for integrating with the live-action footage.[1] The first known matte painting shot was made in 1907 by Norman Dawn (ASC), who improved the crumbling California Missions by painting them on glass for the movie Missions of California.[2] Notable traditional matte-painting shots include Dorothy’s approach to the Emerald City in The Wizard of Oz, Charles Foster Kane’s Xanadu in Citizen Kane, and the seemingly bottomless tractor-beam set of Star Wars.
By the mid-1980s, advancements in computer graphics programs allowed matte painters to work in the digital realm. The first digital matte shot was created by painter Chris Evans in 1985 for Young Sherlock Holmes for a scene featuring a computer-graphics (CG) animation of a knight leaping from a stained-glass window. Evans first painted the window in acrylics, then scanned the painting into LucasFilm’s Pixar system for further digital manipulation. The computer animation (another first) blended perfectly with the digital matte, something a traditional matte painting could not have accomplished.[3]
New technologies
Throughout the 1990s, traditional matte paintings were still in use, but more often in conjunction with digital compositing. Die Hard 2: Die Harder (1990) was the first film to use digitally composited live-action footage with a traditional glass matte painting that had been photographed and scanned into a computer. It was for the last scene, which took place on an airport runway.[4] By the end of the decade, the time of hand-painted matte paintings was drawing to a close, although as late as 1997 some traditional paintings were still being made, notably Chris Evans’ painting of the Carpathia rescue ship in James Cameron’s Titanic.[5]
Paint has now been superseded by digital images created using photo references, 3-D models, and drawing tablets. Matte painters combine their digitally matte painted textures within computer-generated 3-D environments, allowing for 3-D camera movement.[6] Lighting algorithms used to simulate lighting sources expanded in scope in 1995, when radiosity rendering was applied to film for the first time in Martin Scrosese’s Casino. Matte World Digital collaborated with LightScape to simulate the indirect bounce-light affect[7] of millions of neon lights of the 70s-era Las Vegas strip.[8] Speedier computer processing times continue to alter and expand matte painting technologies and techniques.


Traditional and Digital Compositing
Physical compositing
In physical compositing the separate parts of the image are placed together in the photographic frame and recorded in a single exposure. The components are aligned so that they give the appearance of a single image. The most common physical compositing elements are partial models and glass paintings.
Partial models are typically used as set extensions such as ceilings or the upper stories of buildings. The model, built to match the actual set but on a much smaller scale, is hung in front of the camera, aligned so that it appears to be part of the set. Models are often quite large because they must be placed far enough from the camera so that both they and the set far beyond them are in sharp focus. [1]
Glass shots are made by positioning a large pane of glass so that it fills the camera frame, and is far enough away to be held in focus along with the background visible through it. The entire scene is painted on the glass, except for the area revealing the background where action is to take place. This area is left clear. Photographed through the glass, the live action is composited with the painted area. A typical glass shot is the approach to Ashley Wilkes’ plantation in Gone with the Wind. The plantation and fields are all painted, while the road and the moving figures on it are photographed through the glass area left clear.
A variant uses the opposite technique: most of the area is clear, except for individual elements (photo cutouts or paintings) affixed to the glass. For example, a ranch house could be added to an empty valley by placing an appropriately scaled and positioned picture of it between the valley and the camera.
Multiple exposure
An in-camera multiple exposure is made by recording on only one part of each film frame, rewinding the film to exactly the same start point, exposing a second part, and repeating the process as needed. The resulting negative is a composite of all the individual exposures. (By contrast, a “double exposure” records multiple images on the entire frame area, so that all are partially visible through one another.) Exposing one section at a time is made possible by enclosing the camera lens (or the whole camera) in a light-tight box fitted with maskable openings, each one corresponding to one of the action areas. Only one opening is revealed per exposure, to record just the action positioned in front of it.
Multiple exposure is difficult because the action in each recording must match that of the others; so multiple exposure composites typically contain only two or three elements. However, in the 1921 film The Playhouse, Buster Keaton used multiple exposures to appear simultaneously as nine different actors on a stage, perfectly synchronizing all nine performances.
Background projection
Background projection throws the background image on a screen behind the subjects in the foreground while the camera makes a composite by photographing both at once. The foreground elements conceal the parts of the background image behind them. Sometimes, the background is projected from the front, reflecting off the screen but not the foreground subjects because the screen is made of highly directional, exceptionally reflective material. (The prehistoric opening of 2001: A Space Odyssey uses front projection.) However, rear projection has been a far more common technique.
In rear projection, background images (called “plates” whether they are still pictures or moving) are photographed first. For example a camera car may drive along streets or roads while photographing the changing scene behind it. In the studio, the resulting “background plate” is loaded into a projector with the film "flopped" (reversed), because it will be projected onto (and through) the back of a translucent screen. A car containing the performers is aligned in front of the screen so that the scenery appears through its rear and/or side windows. A camera in front of the car records both the foreground action and the projected scenery, as the performers pretend to drive.
Like multiple exposure, rear projection is technically difficult. The projector and camera motors must be synchronized to avoid flicker and perfectly aligned behind and before the screen. The foreground must be lit to prevent light spill onto the screen behind it. (For night driving scenes, the foreground lights are usually varied as the car “moves” along.) The projector must use a very strong light source so that the projected background is as bright as the foreground. Color filming presents additional difficulties, but can be quite convincing, as in the famous crop duster sequence in Alfred Hitchcock’s North by Northwest. Because of its complexity, rear projection has been largely replaced by digital compositing with, for example, the car positioned in front of a blue or green screen.