Datasheet

Project: Creating Lights and Shadows  17

As you adjust the materials, render out additional tests in the Render View window. To

save time, render out only the region of interest. You can deﬁ ne a region by LMB+dragging

in the Render View render area to form a red region box. After releasing the mouse, click the

Render Region button.

Aside from the Color and Diffuse attributes, it’s important to adjust attributes control-

ling specular highlights. For example, the render shown in Figure 1.17 features black plas-

tic parts with intense specular highlights. The highlights reduce the overall contrast for

the plastic surfaces and thus make them appear milky. In particular, the Ear_Cup geom-

etry carries large areas that verge on pure white. To defeat the overly intense specular high-

lights, adjust the Eccentricity, Specular Roll Off, and Specular Color attributes. Reducing

Eccentricity creates a smaller highlight. Lower Specular Roll Off and/or Specular Color

values reduce the highlight intensity. For the Ear_Cup geometry, the following settings

work well (assuming the Key light’s Intensity is set to 0.4):

Color: Dark gray (RGB values 0.02, 0.02, 0.02)

Diffuse: 0.3

Eccentricity: 0.15

Specular Roll Off: 0.3

Specular Color: Medium gray (the default value)

Each material may require its own unique set of specular settings (see Figure 1.18).

Note that you can change the Specular Color to a nonwhite color. For example, the head-

phone’s grommets are a semitransparent plastic. By setting the corresponding material’s

Specular Color to a yellow-gold, the highlight becomes more subtle.

Figure 1.17

Headphones lit with

an area light serving

as a key. The Diffuse

and Color attributes

of several materials

are adjusted. A

sample file is saved

as headphones

-step2.ma on

the DVD.

903278c01.indd 17 4/13/11 10:08:49 AM