Lighting in gmax simulates natural lighting, but is simpler than natural lighting.
The intensity of a light is its HSV Value. At full value (255), the light is at its brightest; at 0, the light is completely dark.
See Designing Materials for more information about material color and how it interacts with light intensity.
A surface is fully illuminated when the angle of incidence is 0 degrees (that is, the light source strikes the surface perpendicularly). There is no attenuation, and the light is white. If the angle of incidence increases, attenuation is in effect, or if the light has a color, the surface intensity can be reduced.
gmax uses a vector from the light object to the face, along with the face normal, to calculate the angle of incidence.
In other words, the position and orientation of the light, relative to the object, are what control the angle of incidence in a scene. The Place Highlight command is one way to fine-tune the location of a light.
By default, gmax lights have no attenuation. To shade a scene with attenuation, you turn it on for one or more lights. All lights support attenuation.
gmax lets you explicitly set where attenuation begins and where it ends. This is partly so you donÆt have to worry about setting up strictly realistic distances between light objects and the objects they illuminate. More importantly, this feature lets you fine-tune the effect of attenuation.
In outdoor scenes, attenuation can enhance the effect of distance.
In an indoor setting, attenuation is useful for low-intensity light sources such as candles.
gmax lighting does not calculate the effect of light reflected from objects in the scene.
Ambient light affects contrast. The higher the intensity of ambient light, the lower the contrast in the scene.
The color of ambient light tints the scene. Sometimes ambient light is bounced light that gets its color from other objects in the scene. Most of the time, however, the color of ambient light should be the complement of the color of the principal light source for the scene.
Tip: To better simulate reflected light and variations in it due to the varying reflectivity of objects in the scene, you can add more lights to a scene and set them to exclude the objects you donÆt want them to affect. You can also set up lights to affect only the ambient component of surfaces. See General Lighting Parameters.
You can set the color of gmax lights. You can use the RGB values for color temperatures as a guide for the principal lighting of a scene; see Properties of Light. Be aware, however, that we tend to perceive scenes as always being lit by white light (this is a perceptual phenomenon known as color constancy), so accurately reproducing the color of a light source can make the scene appear to be tinted oddly. Use the light source values as a general guideline only.
Scenes have no shadows unless you explicitly turn them on. Shadows are caused by one object blocking the path of light. If you donÆt cast shadows, light passes through objects and each object is lit as if other objects were not there. In other words, unless you turn on shadows, the relative position of objects has no effect on how they are lit.
See Shadow Parameters.