3ds Max 2012 Bible - Kelly L. Murdock [246]
Figure 20.8 shows the Exclude/Include dialog box. This dialog box also recognizes any Selection Sets that you've previously defined. You select them from the Selection Sets drop-down list.
As an example of the Exclude/Include feature, Figure 20.9 shows the elk model with the antlers (left) and its body (right) excluded from the shadows pass.
FIGURE 20.8
The Exclude/Include dialog box lets you set which objects are excluded or included from being illuminated.
FIGURE 20.9
Using the Exclude/Include dialog box, you can exclude objects from casting shadows.
The Intensity/Color/Attenuation rollout
In the Intensity/Color/Attenuation rollout, the Multiplier value controls the light intensity. A light with a Multiplier set to 2 is twice as bright as a light with its Multiplier set to 1. Higher Multiplier values make a light appear white regardless of the light color. The Multiplier value can also be negative. A negative value can be used to pull light from a scene but should be used with caution.
Tip
Adding and positioning another light typically is better than increasing the multiplier. •
To the right of the Multiplier value is a color swatch. Clicking the color swatch opens a color selector where you can choose a new light color.
Attenuation is a property that determines how light fades over distance. An example of this is a candle set in a room. The farther you get from the candle, the less the light shines.
You use three basic parameters to simulate realistic attenuation. Near Attenuation sets the distance at which the light begins to fade, and Far Attenuation sets the distance at which the light falls to 0. Both these properties are ranges that include Start and End values. The third parameter sets the Decay value, which simulates attenuation using a mathematical formula to compute the drop in light intensity over time.
Selecting the Use option enables the Near and Far Attenuation values; both have Start and End values that set the range for these attenuation types. The Show option makes the attenuation distances and decay values visible in the viewports. The three types of decay from which you can choose are None, Inverse, and Inverse Square. The Inverse type decays linearly with the distance away from the light. The Inverse Square type decays exponentially with distance.
Note
The Inverse Square type approximates real lights the best, but it is often too dim for computer graphic images. You can compensate for this by increasing the Multiplier value. •
Spotlight and directional light parameters
The Spotlight Parameters rollout includes values to set the angular distance of both the Hot Spot and Falloff cones. The Show Cone option makes the Hotspot and Falloff cones visible in the viewport when the light is not selected. The Overshoot option makes the light shine in all directions like an Omni light, but projections and shadows occur only within the Falloff cone. You can also set the light shape to be circular or rectangular. For a rectangular-shaped spotlight, you can control the aspect ratio. You can use the Bitmap Fit button to make the aspect ratio match a particular bitmap.
The Directional Light Parameters rollout, which appears for Direct light types, is identical to the Spotlight Parameters rollout and also includes settings for the Hot Spot and Falloff values.
Advanced Effects
Options in the Affect Surface section of the Advanced Effects rollout control how light interacts with an object's surface. The Contrast value alters the contrast between the diffuse and the ambient surface areas. The Soften Diffuse Edge value blurs the edges between the diffuse and ambient areas of a surface. The Diffuse and Specular options let you disable these properties of an object's surface. When the Ambient Only option is turned on, the light affects only the ambient properties of the surface.
Cross-Reference
Find more detail on the Diffuse, Specular, and Ambient properties in Chapter 15, “Using the Slate Material Editor.” •
You can use any light as a projector; you find this option in