About Controlling the Properties of Lights

Every light in a drawing has general and specific lighting properties that can be changed after the light is placed.

General Properties

When a light is selected, its properties can be changed in the Properties Inspector.

The following properties are common to all lights:

Photometric Properties

Photometric lighting offers additional properties that make the lighting different than standard lighting. The following properties are under the Photometric properties panel:

If you select Web in the Type property for a photometric light, additional properties are offered in the Photometric Web and Web offsets panel in the Lighting category.

Spotlight Properties: Hotspot and Falloff

When light from a spotlight falls on a surface, the area of maximum illumination is surrounded by an area of lesser intensity.

The greater the difference between the hotspot and falloff angles, the softer the edge of the light beam. If the hotspot and falloff angles are near equal, the edge of the light beam is sharp. Both values can range from 0 to 160 degrees. You can adjust these values directly with the Hotspot and Falloff grips.

Point Light and Spotlight Attenuation Properties

Attenuation controls how light diminishes over distance. The farther away an object is from a light, the darker the object appears. You can specify no attenuation, inverse linear, or inverse squared. Attenuation is not active for photometric lights.

Another way to control the start point and end point of light is to use limits. Limits work like clipping planes to control where light is first emitted and where it stops. Using limits can increase performance by removing the need for the program to calculate light levels where the light is already practically invisible.

Geometry Properties

Geometry Properties controls the location and target of the light. If the light is a target point light, spotlight, or weblight, additional target point properties are available. The Target property of a light can also be turned on an off.