Lighting Effects
Another form of shadow effect is a gobo. This term comes from the film industry and refers to a piece of metal or cardboard placed over a directional lighting source with holes cut in it to form a light pattern. Some gobos have horizontal slots to imitate light from a Venetian blind, whereas others have leaf-shaped holes to simulate forest lighting. Many animation programs offer gobos or shadow masks, which enable the artist to use a picture file (for instance, a JPEG drawing of black and white stripes) as a gobo.
Fog is a feature employed by most animation programs to simulate the effect of minute particles evenly dispersed within the 3-D space of your scene. As you know, fog appears in the real world whenever water droplets, dust, or smoke particles permeate the atmosphere. Although real fog can be created in an animation program by the introduction of virtual particles, this technique is extremely render intensive, and animators usually employ their programs' fog feature, which employs a standard set of mathematic simulations to create fog effects. These simulations are quite effective, allowing for density, grain, intensity, and the depth of fog. The result can be as noticeable as a searchlight piercing a cloudbank or as subtle as a gentle softening of the shadows cast onto a sun porch on a spring morning.
In real-life photography, flares are considered an undesirable side effect of lighting and photographic lens design. Cinematographers go to great lengths to avoid lens flares (the polygonal shapes of translucent color that repeat themselves across a scene when the angle of light is oblique enough to enter the lens). Animators, however, tend to employ lens flares and other kinds of flares as a means of building the credibility of reality. (I suppose if you have lens flares, it implies you used a lens!)
Flares come in a variety of patterns and densities, and in some programs, the tools to make flares may be scattered about in different tool sets. When creating lens flares, the software will usually allow you to determine how many lens element flares are stacked2 and how large the effect will be in your scene. Other flares include circles and star patterns, and the program will enable control over the amount of points in the star, the density gradient of the circle, and even the presence of a halo. Halos are currently popular in large explosions, where a flare will be preceded by a horizontal halo, depicting the effect of the concussion wave of the explosion.
Glow is another lighting effect, often combined with flares. Glow can be used alone or be modified by a texture map or random noise modifier. When modified, glow and other lighting effects are distorted from their normally regular distribution patterns into patterns of varied intensity that are determined by the levels of black and white in the modifying source. In your chosen program, look for the capability to employ texture maps or random noise in lighting effects. Such tools will usually enable the selection of the modifying source graphic (or noise source) and the amount of the distorting effect. The distortion can also be varied in time by using
2Incidentally, the quality of a photographic lens can be determined from its flare by counting the number of stacked polygons. Each polygon denotes a separate lens element. The more elements, the more expensive the lens.
keyframes in order to add animated realism. Keep in mind that using keyframes in any lighting increases their render time.
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