15 // Lighting in 3D
A Light Menu Now that you have a feeling for how lights work in general, we can get into the specifics of the different Light Types, plus the Intensity and Color parameters. If you want to play around with these parameters as we describe them, use the popup menu along the top of the Comp panel to select Close All. Then open [Ex.02a], which contains another pair of 3D layers and a light. If the light’s parameters are not already revealed, select Light 1 and type AA to reveal its Options in the Timeline panel. Also make sure the Switches column is open in the Timeline panel.
Spot Light
Spot lights are directional; they also have a cone that defines how wide an area they illuminate. Background courtesy Digital Vision/Inner Gaze.
A series of Spot lights with narrow cones, placed close to a layer, can create a nice effect. Animate each one’s Point of Interest to create a searchlight feel. Image courtesy Digital Vision/Music Mix.
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We’ll start with the Light Type of Spot, as you’re already familiar with it from the previous section. All of the other Light Types are subsets of Spot in that they have fewer Options. Spot lights are directional: Their rays start at their Position and are sprayed out in a cone centered around their Point of Interest. The distance between the Point of Interest and Position has no bearing on how far these rays shoot; all lights in After Effects extend an infinite distance (unlike some 3D programs, which allow you to control a light’s falloff so that it can become weaker over distance). The Cone Angle determines how widely the light rays are sprayed, with a maximum value of 180°. The farther a light is from a layer, the larger the cone of light will appear – think of aiming a flashlight toward objects farther away. The Cone Feather determines how quickly the effect of the light transitions from darkness (the area beyond the cone) to full illumination. Unlike Mask Feather, in which the feather is centered around the mask shape, a light’s Cone Feather does not reach outside the Cone Angle – it only reaches inward. As a result, increasing the Cone Feather has the visual effect of reducing the amount of illumination a light contributes to a scene. In [Ex.02a], scrub the Cone Feather value between 0% and 100% to see how it softens the visual effect of the cone. Leave it at a low value (somewhere between 0% and 30%), and scrub the Cone Angle to watch the spot narrow and widen.