| iTool User's Guide: Visualization Properties |

## Lights

Figure D-25: Visualization Browser with Light Properties Displayed

Figure D-25: Visualization Browser with Light Properties Displayed

Lights properties control the lighting of the data space. These properties are available only for 3-D Surface and Volume visualizations.

Three types of lights can be configured through the Lights properties: Ambient Light, Light 1 (from above), and Light 2 (from below). Each type of light has the same set of properties, as described in Table D-56.

For each property, the type of control and the values that can be assigned are listed. For a description of how a particular control is used, refer to Property Controls.

Table D-56: Property Settings for Lights

Table D-56: Property Settings for Lights
Property | Control Type: Values
--- | ---
Type | String List: Type of light source for this light. Select a type of light from the list. Choose from these options: Ambient: Universal light source with no direction or position. An ambient light illuminates every surface in the scene equally, which means that no edges are made visible by contrast. Ambient light controls the overall brightness and color of the scene. Positional: Supplies divergent light rays so that the edges of surfaces can be made visible by contrast. A positional light source can be located anywhere in the scene. Directional: Supplies parallel light rays from a light source located at an infinite distance from scene. Spotlight: Illuminates only a specific area defined by the light's position, direction, and the cone angle (angle the spotlight covers). Default = Positional
Distance | Number: Distance of the light source from the visualization from -1 (in front of the visualization) to 1 (behind the visualization). Move the slider to change the value. Default = -1 for Ambient Light and Light 1, 1 for Light 2
Intensity | Number: Intensity of this light from 0 (no light) to 1 (bright light). Move the slider to change the value. Default = 0.5 for Ambient Light, 0.8 for Light 1 and Light 2
Color | Color: Color of this light. Click to choose from the default color palette, or specify RGB values. Default = `[255,255,255]` (white)
Cone angle | Number: Angle the spotlight covers from 0º to 180º. Active only when Spotlight type is selected. Move the slider to change the value. Default = 60
Focus attenuation | Number: Floating-point value from 0 to 128 that attenuates the intensity of spotlights as the distance from the center of the cone of coverage increases. This factor is used as an exponent to the cosine of the angle between the direction of the spotlight and the direction from the light to the vertex being lighted. Active only when Spotlight type is selected. Move the slider to change the value. Default = 0

IDL Online Help (March 01, 2006)