Datasheet

Lighting Techniques and Maya Light Types  15

Area The area light possesses a rectangular icon and can be scaled in either the X or Y direc-

tion. Hence, area lights can emulate a source that is transmitted through a plane with a ﬁ xed

size. For example, an area light might re-create sunlight arriving through a window or a

bank of lightbulbs placed behind a rectangular marquee. Area lights are the most physically

accurate of the basic Maya light types. As such, the light intensity is affected by the distance

and angle of the light icon in relation to lit surfaces. Although an area light is represented by

a rectangular icon, it actually functions as an array of point lights. This array causes the area

light to be fairly soft. Nevertheless, area lights operate in one direction; this is indicated by

the small “pointer” extending from the light icon’s center.

Ambient The ambient light is extremely soft and produces little, if any, variation in inten-

sity. By default, the light is a mixture of omnidirectional and directional rays. The light’s

Ambient Shade attribute controls this mixture. If Ambient Shade is lowered from the

default 0.45 to 0, the light becomes equally intense at all points within a scene; this leads

to a ﬂ at, “toon” look. If Ambient Shade is raised to 1.0, the light radiates from the light

icon and is identical to a point light. Ambient lights are suitable as ﬁ ll and are usually

inappropriate as a key.

Volume The volume light acts as a point light but is contained within the volume of the

light’s icon. You can scale the icon to any size. By default, the icon is spherical, but you can

change it to a cylinder or cone through the light’s Light Shape attribute. By default, the light’s

intensity tapers from the icon center to the icon edge. The rapidity of this taper is controlled

by the Color Range and Penumbra gradients. For a surface to be lit by a volume light, it must

rest within the interior of the light icon. For a demonstration of the volume light’s unusual

functionality, see Chapter 2.

Figure 1.15

(Top Row) Maya light types. (Bottom Row) The corresponding real-world lighting scenarios emulated by

Maya lights. From Left to Right: A directional light re-creates the parallel rays of an unobstructed sun; a

point light acts like a lightbulb with omnidirectional rays originating from a specific point; a spot light

simulates the divergent rays of a real-world spotlight from film and stage; an area light duplicates light

arriving from a rectangular plane, such as a window; an ambient light acts like bounced light (in this

case, window light bounced off a floor); a volume light functions as a point light, but the illuminated

surfaces must be placed within the light’s volume shape.

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