3ds Max 2012 Bible - Kelly L. Murdock [479]
When the Automatic Exposure Control option is selected, a new rollout appears in the Environment panel. This rollout includes settings for Brightness, Contrast, Exposure Value, and Physical Scale. You also can enable Color Correction, select a color, and select an option to Desaturate Low Levels. The Contrast and Brightness settings can range from 0 to 100. A Contrast value of 0 displays all scene objects with the same flat, gray color, and a Brightness value of 100 displays all scene objects with the same flat, white color. The Exposure Value can range from –5 to 5 and determines the amount of light allowed in the scene.
Another exposure control option is Linear Exposure Control. Although this option presents the same settings as the Automatic Exposure Control, the differences between the minimum and maximum values are a straight line across the light spectrum.
Tip
The tricky part is to know when to use which Exposure Control. For still images, the Automatic Exposure Control is your best bet, but for animations, you should use the Logarithmic Exposure Control. Automatic is also a good choice for any scenes that use many lighting effects. Using any of the exposure controls besides the Logarithmic Exposure Control when animating can lead to flickering. The Linear Exposure Control should be used for low dynamic range scenes such as nighttime or cloudy scenes. •
The Logarithmic Exposure Control option replaces the Exposure Value setting with a Mid Tones setting. This setting controls the colors between the lowest and highest values. This exposure control option also includes options to Affect Indirect Only and Exterior Daylight. You should enable the Affect Indirect Only option if you use only standard lights in the scene, but if your scene includes an IES Sun light, then enable the Exterior Daylight option to tone down the intensity of the light.
Cross-Reference
You should always use the Logarithmic Exposure Control setting when enabling the advanced lighting features because it works well with low-level light. You can learn more about the advanced lighting radiosity features in Chapter 45, “Working with Advanced Lighting, Light Tracing, and Radiosity.” •
Pseudo Color Exposure Control
As you work with advanced lighting solutions and with radiosity, determining whether interior spaces and objects have too much light or not enough light can be difficult, especially when comparing objects on opposite sides of the scene. This is where the Pseudo Color Exposure Control option comes in handy.
This exposure control option projects a band of colors (or grayscale) in place of the material and object colors that represent the illumination or luminance values for the scene. With these pseudo-colors, you can quickly determine where all the lighting is consistent and where it needs to be addressed.
In the Pseudo Color Exposure Control rollout, shown in Figure 46.1, you can select to apply the colors to show Illumination or Luminance. You also can select to use a Colored or Grayscale style and to make the Scale Linear or Logarithmic. The Min and Max settings let you control the ranges of the colors, and a Physical Scale setting is included. The color (or grayscale) band is shown across the bottom of the rollout with the values for each color underneath.
FIGURE 46.1
The Pseudo Color Exposure Control rollout can display illumination and luminance values as colors.
When this exposure control is used, the associated render element is automatically set in the Render Elements rollout of the Render Scene dialog box. If the scene is rendered, then the appropriate (Illumination or Luminance) render element is also rendered.
Cross-Reference
See Chapter 49, “Compositing with Render Elements and the Video Post Interface,” for more on render elements. •
Photographic Exposure Control
If you're comfortable working with camera settings such as Shutter Speed, Aperture, and Film Speed, then the Photographic Exposure Control puts these settings at your fingertips using real-world values. Even if you're