The General Parameters rollout is displayed for all types of lights. These controls turn a light on and off, and exclude or include objects in the scene. On the Modify panel, the General Parameters rollout also lets you control the light’s target object and change the light from one type to another.
The General Parameters rollout also includes some settings for shadows. Shadows can be easily turned on or off. In this rollout, you can defer to the global settings by selecting the Use Global Settings option. This option helps to maintain consistent settings across several lights. It applies the same settings to all lights, so that changing the value for one light changes that same value for all lights that have this option selected.
Figure 7-7: General Parameters rollout
You can also select from a drop-down list whether the shadows are created using Area Shadows, a Shadow Map, regular or advanced raytraced shadows, or a mental ray shadow map. A new rollout appears depending on the selection that you make.
Exclude button excludes selected objects from the effects of the light. Click this button to display the Exclude/Include dialog. Excluded objects still appear lit in shaded viewports. Exclusion takes effect only when you render the scene.
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. 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 the effect of light diminishing over distance. In 3ds max, you can set attenuation values explicitly. The effects can vary from real-world lights, giving you more direct control over how lights fade in or fade out.
Figure 7-8: Intensity/Color/Attenuation rollout
All light types have a Shadow Parameters rollout except Skylight and IES Sky. It lets you set shadow colors and other general shadow properties. This rollout can be used to select a shadow color by clicking the color swatch. The default color is black. The Dens setting stands for “Density” and controls how dark the shadow appears. Lower values produce light shadows, and higher values produce darker shadows. This value can also be negative.
Figure 7-9: Shadow Parameters rollout
The Map option, like the Projection Map, can be used to project a map along with the shadow color. The Light Affects Shadow Color option alters the Shadow Color by blending it with the light color if selected.
In the Atmosphere Shadows section, the On button lets you determine whether atmospheric effects, such as fog, can cast shadows. You can also control the Opacity and the degree to which atmospheric colors blend with the Shadow Color.
Spotlight or Directional Parameters
The parameters rollout for spotlights and directional lights are identical. The same tools for spotlights and directional lights behave slightly differently, as outlined below.
Figure 7-10: Spotlight Parameters & Directional Parameters
This area describes all the adjustable parameters of the light “cone,” which is in fact not always cone-shaped. A spotlight’s illumination shape does look like a cone, but a directional light’s light “cone” is cylindershaped.
Checking the Show Cone check box will allow you to see the light cone even if the light is not selected.
The Overshoot check box allows the directional light or spotlight to illuminate areas outside the light cone. This is helpful in a number of ways. For example, if you have a large outdoor scene, you will have to scale your directional light up to encompass the entire scene. Make a mistake and you’ll see the cone edge in your render. But if you select Overshoot, there will be no cone edge and the entire world will be illuminated by the directional light. In this way, a directional light is made to behave a little like the sun. For spotlights, sometimes you have your spotlight in the perfect position, but you just catch the edge of the beam in frame. Instead of having to reposition your light, just check Overshoot.
Most normal lights have a hotspot somewhere near the center of their light beam. This is usually because directed light, like that from a stage spotlight, uses imperfect optics, and either the reflective mirror behind the lamp or the lenses are causing imperfect light focus to concentrate some light in one area and less in another.
Falloff/Field is the area of illumination falling outside of the hotspot and going as far as the edge of illumination. Using combinations of Hotspot/Beam and Falloff/Field, you can create very hard-edged theatrical spotlights, very soft-edged light, or anything in between.
You can easily switch your beam shape from a cone to a rectangle with the Circle and Rectangle buttons.
The Aspect numeric input and spinner controls how rectangular in shape a Rectangle beam is. For example, if you enter an aspect of 1.0, the light beam will be perfectly square. If you enter an aspect of 2.0, the beam will be twice as wide as it is high, and so forth.
If you choose a rectangular beam, you can automatically set the aspect with the Bitmap Fit button. Selecting this button brings up a file dialog. When you select a valid image file, the light’s aspect will automatically be adjusted to match that of the selected image.
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.
Figure 7-11: Advanced Effects rollout
You can use any light as a projector; you find this option in the Advance Effects rollouts. Selecting the Map option enables you to use the light as a projector. You can select a map to project by clicking the button to the right of the map option. You can drag a material map directly from the Material/Map Browser onto the Projector Map button.