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"Is CHILDHOOD always the best time ?”
15 years ago
Visual effects may be divided into at least four categories:
- Matte paintings and stills: digital or traditional paintings or photographs which serve as background plates for keyed or rotoscoped elements
- Digital animation: modeling, computer graphics lighting, texturing, rigging, animating, and rendering computer generated 3D characters, particle effects, digital sets, backgrounds, etc..
Visual effects (or 'VFX' for short) is the term given in which images or film frames are created and manipulated for film and video. Visual effects usually involve the integration of live-action footage with computer generated imagery or other elements (such as pyrotechnics or model work) in order to create environments or scenarios which look realistic, but would be dangerous, costly, or simply impossible to capture on film. They have become increasingly common in big-budget films, and have also recently become accessible to the amateur filmmaker with the introduction of affordable animation and compositing software.
The illusions used in the film, television, and entertainment industries to simulate the imagined events in a story are traditionally called special effects (a.k.a. SFX or SPFX). In modern films, special effects are usually used to alter previously-filmed elements by adding, removing or enhancing objects within the scene. The use of special effects is more common in big-budget films, but affordable animation and compositing software enables even amateur filmmakers to create professional-looking effects.
Special effects are traditionally divided into the categories of optical effects and mechanical effects. In recent years, a greater distinction between special effects and visual effects has been recognized, with "visual effects" referring to post-production and optical effects, and "special effects" referring to on-set mechanical effects.
Optical effects (also called visual or photographic effects), are techniques in which images or film frames are created and manipulated for film and video. Optical effects are produced photographically, either "in-camera" using multiple exposure, mattes, or the Schüfftan process, or in post-production processes using an optical printer or video editing software. An optical effect might be used to place actors or sets against a different background, or make an animal appear to talk.
Mechanical effects (also called practical or physical effects), are usually accomplished during the live-action shooting. This includes the use of mechanized props, scenery and scale models, and pyrotechnics. Making a car appear to drive by itself, or 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, or makeup can be used to make an actor look like a monster.
Since the 1990s, computer generated imagery (CGI) has come to the forefront of special effects technologies. CGI gives film-makers greater control, and allows many effects to be accomplished more safely and convincingly. As a result, many optical and mechanical effects techniques have been superseded by CGI.
Special effects are traditionally divided into the categories of optical effects and mechanical effects. In recent years, a greater distinction between special effects and visual effects has been recognized, with "visual effects" referring to post-production and optical effects, and "special effects" referring to on-set mechanical effects.
Optical effects (also called visual or photographic effects), are techniques in which images or film frames are created and manipulated for film and video. Optical effects are produced photographically, either "in-camera" using multiple exposure, mattes, or the Schüfftan process, or in post-production processes using an optical printer or video editing software. An optical effect might be used to place actors or sets against a different background, or make an animal appear to talk.
Mechanical effects (also called practical or physical effects), are usually accomplished during the live-action shooting. This includes the use of mechanized props, scenery and scale models, and pyrotechnics. Making a car appear to drive by itself, or 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, or makeup can be used to make an actor look like a monster.
Since the 1990s, computer generated imagery (CGI) has come to the forefront of special effects technologies. CGI gives film-makers greater control, and allows many effects to be accomplished more safely and convincingly. As a result, many optical and mechanical effects techniques have been superseded by CGI.
Compositing is a technique by which one shot is super-imposed on another, resulting in a composite shot. A common example is our everyday weather forecast on TV. The weather map is a separate computer generated shot onto which the announcer is super-imposed, making it look as if he/she is standing in front of a giant TV screen flashing different weather images.
By separating the foreground and the background into distinct layers, we can manage each layer with much more control. As you will see, this technique alone has given rise to enormous possibilities in the special effects realm. Let us study this technique with the help of an example. The following shot involves flying a plane through a congested city, between tall skyscrapers. Obviously, this is a very risky shot, and would not be permitted by any sane mayor of any large city. The only alternative is to resort to special effects.
Sources : Internet
Look at a bright light for a few seconds and then abruptly close your eyes. The image of the light seems to stay in your eyes a little longer even though your eyes are closed.
This phenomenon is termed as Persistence of Vision because the vision seems to persist for a brief moment of time.
When the retina of the eyes are excited by light, they send impulses to the brain which are then interpreted as an image by the visual cortex in the brain. The cells in the retina continue to send impulses even after the incident light is removed. This continues for a few fractions of a second till the retinal cells return back to normal. Until that time, the brain continues to receive impulses from the retina, and hence seems to perceive an image of the source of light, giving rise to the phenomenon called Persistence of Vision.
This phenomenon is termed as Persistence of Vision because the vision seems to persist for a brief moment of time.
When the retina of the eyes are excited by light, they send impulses to the brain which are then interpreted as an image by the visual cortex in the brain. The cells in the retina continue to send impulses even after the incident light is removed. This continues for a few fractions of a second till the retinal cells return back to normal. Until that time, the brain continues to receive impulses from the retina, and hence seems to perceive an image of the source of light, giving rise to the phenomenon called Persistence of Vision.
The Principle of Motion Picture is totally based on the phenomenon of Persistence of Vision. Without it, motion picture as we know it simply would'nt exist. Our eyes can retain a picture for a fraction of a second after seeing one. Before this time frame expires, if a another similar picture is shown in its place, the eyes see it as a continuation of the first picture, and don't perceive the gap between the two.
If a series of still pictures depicting progressively incrementing action is flashed before the eyes in rapid succession, the eyes see it as a scene depicting smooth, flowing action. All visual media (Movies, TV, Electronic Displays, Laser Light Shows, etc) exploit this phenomenon.
Thanks to Persistence of Vision, our entertainment industry could make a transition from perpetual live shows like dance and dramas, to recordable entertainment like movies.
If a series of still pictures depicting progressively incrementing action is flashed before the eyes in rapid succession, the eyes see it as a scene depicting smooth, flowing action. All visual media (Movies, TV, Electronic Displays, Laser Light Shows, etc) exploit this phenomenon.
Thanks to Persistence of Vision, our entertainment industry could make a transition from perpetual live shows like dance and dramas, to recordable entertainment like movies.
Motion of an object is the continuous displacement of the object in space with reference to another object. In the absence of a reference object, motion ceases to be apparent. What this means is that motion is always measured in relation to another object, which is used as a reference point.
When we drive, the road & the surroundings move past us. Thus we get the sensation of motion. So the road & surroundings are our reference points. When we fly, the earth beneath us is our reference point. But as you can see, the closer the reference point, the more acute the sense of motion. That's why astronauts in orbit seldom sense speed (though they are moving at thousands of miles an hour ) because earth, their only reference point is quite far away.
OK, but what has this got to do with Special Effects ?! A Sfx technique called Compositing totally relies on the way our mind perceives motion. Compositing is one of the most useful tools in a Sfx technician's bag of tricks. Keep these two in mind; the object, and its reference point(s); both of these are necessary to perceive motion in a scene.
When we drive, the road & the surroundings move past us. Thus we get the sensation of motion. So the road & surroundings are our reference points. When we fly, the earth beneath us is our reference point. But as you can see, the closer the reference point, the more acute the sense of motion. That's why astronauts in orbit seldom sense speed (though they are moving at thousands of miles an hour ) because earth, their only reference point is quite far away.
OK, but what has this got to do with Special Effects ?! A Sfx technique called Compositing totally relies on the way our mind perceives motion. Compositing is one of the most useful tools in a Sfx technician's bag of tricks. Keep these two in mind; the object, and its reference point(s); both of these are necessary to perceive motion in a scene.
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