Use Spotlights

A spotlight can be directed towards an object.

Spotlights

A spotlight distribution casts a focused beam of light like a flashlight, a follow spot in a theater, or a headlight. A spotlight emits a directional cone of light. You can control the direction of the light and the size of the cone. Like a point light, a spot light can be manually set to attenuate its intensity with distance. However, a spotlight's intensity will also always attenuate based on the angle relative to the spot's target vector. This attenuation is controlled by the hotspot and falloff angles of the spotlight. Spotlights are useful for highlighting specific features and areas in your model. A free spotlight (FREESPOT) is similar to spotlight. A spotlight has target properties.

Spotlights in Photometric Workflow

In photometric workflow, the hotspot intensity falls to 50 percent. The hotspot for standard lighting is at 100 percent. At its falloff angle, intensity of the spotlight falls to zero. Additional properties become available for a point light when LIGHTINGUNITS is set to 1 (American units) or 2 (International SI units) for photometric lighting:

Lamp Intensity. Specifies the inherent brightness of the light. Specifies the intensity, flux, or illuminance of the lamp.
Resulting Intensity. Gives the final brightness of the light. (Product of lamp intensity and intensity factor. Read-only.)
Lamp Color. Specifies the inherent color of the light in Kelvin temperature or standard.
Resulting Color. Gives the final color of the light. This is determined by a combination of the lamp color and the filter color. (Product of lamp color and filter color. Read-only.)

NoteWhen the drawing lighting units are photometric, the attenuation type property becomes disabled. Photometric lights have fixed, inverse-square attenuation. The hotspot falloff attenuation in the rendered image varies from standard lighting, as it uses a different mathematical basis.

The additional information about these properties are available under Lighting Properties. The following image is an example of a photometric spotlight and lighting properties palette with the photometric properties outlined:

Procedure

To create a spotlight

To create a photometric spotlight and change photometric properties

Click Render tab Lights panel Lighting Units drop-down Generic Lighing Units.
No lighting units are used and standard (generic) lighting is enabled.

NoteAlternatively, you can enter lightingunits at the Command prompt and set the value to 0 for standard (generic) lighting.
Click Render tab Lights panel Create Light drop-down Spot.
Click in the drawing to specify a location for the light.
Click to specify a target for the spotlight.
At the Command prompt, enter n and enter a name. This name will appear in the properties and in the Lights in Model window (LIGHTLIST).
You can continue to specify properties by entering options, or you can exit and set properties interactively. When you use the interactive method, you can see the results of your changes as you work.
Press Enter twice to exit the command.
Select the light and use grip tools to change the light.
To change properties, right-click the light. Click Properties. Use the Lighting Properties palette to change the photometric properties.

To create a free spot light in photometric lighting workflow

To create a spotlight tool

Quick Reference

Commands

System Variables

DEFAULTLIGHTING

Turns on and off default lighting in place of other lighting.

DEFAULTLIGHTINGTYPE

Specifies the type of default lighting, old or new.

LIGHTGLYPHDISPLAY

Turns on and off the display of light glyphs.

LIGHTINGUNITS

Controls whether generic or photometric lights are used, and specifies the lighting units for the drawing.

LIGHTSINBLOCKS

Controls whether lights contained in blocks are used when rendering.

LINEARBRIGHTNESS

Controls the brightness level of the viewport when using default lighting or generic lights.

LINEARCONTRAST

Controls the contrast level of the viewport when using default lighting or generic lights.

LOGEXPBRIGHTNESS

Controls the brightness level of the viewport when using photometric lighting.

LOGEXPCONTRAST

Controls the contrast level of the viewport when using photometric lighting.

LOGEXPDAYLIGHT

Controls if the exterior daylight flag is enabled when using photometric lighting.

LOGEXPMIDTONES

Controls the mid tones level of the viewport when using photometric lighting.

RENDERUSERLIGHTS

Controls whether to override the setting for viewport lighting during rendering.