Almost everyone today must have seen science-fiction and action movies with hi-tech special effects. These effects are a culmination of not only the developments in computer science and technology in the last two decades, but also the accompanying developments in computer animation and graphics technologies.

In this blog we take a tour of the world of computer graphics and special effects and see the types of effects that are in use today as well as some behind-the-scenes action that goes into making these scenes appear as real as they do on the screens.

What are special effects?

Special effects are a combination of detailed art and high-level technology. It consists of understanding how human begins perceive the world through sound and visual sensory parts of their body and their brain.

Persistence of Vision: When a related sequence of still images is passed at a particular speed (minimum 15 frames/sec.) in front of human eye, the human brain perceives it as a single image with motion, i.e., it perceives the second, third images as a continuation of the first image. This is because a human’s nerve impulses are slow as compared to speed of light.

Principle of Motion Pictures: Persistence of vision of the human eye is the principle behind motion pictures in which camera, lights, audio, computer generated objects (CG) and other visual media are employed to exploit this phenomenon.

What is motion: Motion of an object is the continuous displacement of the object in space with reference to another object. This phenomenon forms the basis for compositing technology.

Types of special effects:

Computer Effects:

Some of the popular computer generated special effects are:

• A complete blue or green screen
• Computer animations or cartoon films
• Compositing
• Morphing/Warping

Humanized Effects:

These are some of the effects generated by a computer and used in films:

• Use of Latex
• Creating the illusion of rain, snow, wind and fire
• Showing realistic on-screen blood bags/bullet hits
• Explosions

Computer Effects:

These are effects generated with the help of computer technologies. Some of these effects are as follows:

Showing a complete blue/green screen: In this technique, a blue/green background screen is used in a scene. This scene is then made to overlap on another and the blue/green colored background removed with the help of compositing software’s. This technique needs a special kind of compositing, where the mask is calculated from the foreground image.

Below is an excellent example of action photo compositing, sometimes referred to as transitional photography (source: http://www.photosfan.com).

Computer Animation: For generating computer animations, real footage is first shot and is then converted to animation using compositing software. A good example of this technique would be Gollum, a computer generated character in the movie ‘The Lords of the Rings’.

Cartoons Frames: For displaying real characters with cartoons, cartoon character is used with real footages. The best example of this technique is the movie ‘SpaceJam’ (shown below, source: http://animatedviews.com/)

Using Physical Models for Animation: In this technique, a physical model (mechanical robot) is used to depict the character on screen. Good examples of this technique would be the films ‘Jurassic Park’, ‘Godzilla’ etc

Morphing: This is a special-effects technique that creates a smooth, controlled transformation of one image, character or movie into another.

The figure above shows the morphing of a person’s face to that of a tiger (source: http://www.blorge.com)

Warping: Warping is also the same as morphing, except that it uses only one image or movie. An example of warping created using Adobe Photoshop is shown below.

Humanized Effects:

These are effects which are generated manually. They are generated as follows:

Using latex: Latex is a material used in commercial make-ups. It can add scars on faces, extra eyes on ‘monster’ heads, and can also make young people look old and vice versa. A good example of this would be the movies ‘The Nutty Professor’ (as below), ‘Lord of the Rings’ etc.

Rain: Computer generated rain makes it difficult to give the realistic look and feel of real rain since it does not wet the actors’ clothes. Hence, film makers arrange for artificially created rain-like effects.

Snow: Snow machines are available which help in creating snow for the shots.

Wind: Production staff uses large fans and high speed blowers to create good wind effects.

Fire: For creating massive fires, experts are called, who create huge fire shots with fire machines, and which can easily be turned on for massive fire scenes, as well as off just be pressing a button.

Blood bags/bullet hits: The blood bursting out from a person in the movies is achieved by a small, battery-triggered explosive charge, causing a blood-filled bag to burst out. A small, 9V battery is used to burst a squib (fireworks consisting of a tube filled with powder that burns with a fizzing noise), which has to place under the character’s costume.

Explosions: At times when computer generated explosions are not effective, and for realistic looks, a pyrotechnic machine is used to achieve the explosive effects.

Technology used to create special effects (Software):

The following are some of the software used to create special effects:

• Autodesk Combustion
• Autodesk Inferno
• Autodesk Flame
• Autodesk Flint
• Adobe After Effects
• Digital Fusion
• Elastic Reality
• Boris FX
• Hollywod FX
  

In summary, we have seen in this blog post that advancements in special effects have revolutionized entertainment and have made movies seem life-like. This may just be the beginning of special effects in movies; the best is yet to come.

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