AutoCAD 2008 User's
Guide > Create Realistic
Images and Graphics > Add Lighting to
Your Model > Illuminate a
Scene >
Guidelines for Lighting
The guidelines for lighting used by photographers, filmmakers, and stage designers can also 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.
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.
In clear weather, the color of sunlight is a pale yellow: for example, RGB values of 250, 255, 175 (HSV 45, 80, 255). Cloudy weather can tint sunlight blue, shading into dark gray for stormy weather. Particles in the air can give sunlight an orange or brownish tint. At sunrise and sunset, the color can be more orange or red than yellow.
Shadows are more distinct the clearer the day is, and can be essential for bringing out the three-dimensionality of a naturally lit scene.
A directional light can also simulate moonlight, which is white but dim compared to the sun.
A scene illuminated by point lights, spotlights, or distant lights are artificially illuminated. Therefore, it can be helpful to know how light naturally behaves.
When light rays strike a surface, the surface reflects them, or at least some of them, enabling us to see the surface. The appearance of a surface depends on the light that strikes it combined with the properties of the surface material, such as color, smoothness, and opacity.
Other factors, such as a light’s color, intensity, attenuation, and angle of incidence also play a role in how objects in a scene appear.
