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Photometric Lights
Photometric lights are physically correct lights. Physically correct lights
attenuate as the square of the distance.
Photometric properties can be added to both artificial lights and natural lights.
Natural lights are the sun and the sky. The natural lighting is represented
interactively by a viewport background type.
You can create lights with various distribution and color characteristics, or
import specific photometric files available from lighting manufacturers.
Photometric lights always attenuate using an inverse-square falloff, and rely
on your scene to use realistic units.
Illuminate a Scene
You can add point lights, spotlights, and distant lights and set the location
and photometric properties of each.
You can use a command to create a light, or you can use a button on the
Lights toolbar or the Lights panel on the ribbon. You can use the Properties
Inspector palette to change the color of a selected light or other properties.
You can also store a light and its properties on a tool palette and use it again
in the same drawing or another drawing.
Guidelines for Lighting
The guidelines for lighting used by photographers, filmmakers, and stage
designers can help you set up the lighting for scenes.
Your choice of lighting depends on whether your scene simulates natural or
artificial illumination. Naturally lit scenes, such as daylight or moonlight, get
their most important illumination from a single light source. Artificially lit
scenes, on the other hand, often have multiple light sources of similar
intensity.
Natural Light
For practical purposes at ground level, sunlight has parallel rays coming from
a single direction. The direction and angle vary depending on the time of day,
the latitude, and the season.
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