Tuesday, October 8, 2019

SPOTLIGHT (Command)

Creates a spotlight that emits a directional cone of light.
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A spotlight distribution casts a focused beam of light like a flashlight, a follow spot in a theater, or a headlight.
Note: Starting with AutoCAD 2016-based products, all standard lights are calculated as photometric lights. It is recommended to update all standard lights in a scene to photometric lights. Photometric lighting is enabled by setting the LIGHTINGUNITS system variable to 1 or 2.
The following prompts are displayed.
Note: The options for this command vary slightly depending on the LIGHTINGUNITS setting.

Source location

Sets the location for the spotlight. Enter coordinate values or click a location in the drawing area.

Source location

Sets the spotlight target. Enter coordinate values or click a location in the drawing area.

Name

Specifies the name of the light. You can use uppercase and lowercase letters, numbers, spaces, hyphens (-), and underscores (_) in the name.

Intensity/Intensity factor

Sets the intensity or brightness of the light. The range is 0.00 to the maximum value that is supported by your system.

Hotspot

Specifies the angle that defines the brightest cone of light, which is known to lighting designers as the beam angle. This value can range from 0 to 160 degrees or the equivalent values based on AUNITS.

Falloff

Specifies the angle that defines the full cone of light, which is also known as the field angle. This value can range from 0 to 160 degrees. The default is 50 degrees or the equivalent values based on AUNITS. The falloff angle must be greater than or equal to the hotspot angle.

Status

Turns the light on and off.

Photometry

Photometry is the measurement of the luminous intensities of visible light sources.
In photometry, luminous intensity is a measure of the perceived power emitted by a light source in a particular direction. Luminous flux is the perceived power per unit of solid angle. The total luminous flux for a lamp is the perceived power emitted in all directions. Luminance is the total luminous flux incident on a surface, per unit area.
Note: The Photometry option is available only when the LIGHTINGUNITS system variable is set to 1 or 2.
Intensity
Enter an intensity value in candelas, flux value, or illuminance value.
  • Intensity. Sets intensity based on candelas (cd), the SI base unit of luminous intensity. This value sets the perceived power emitted by a light source in a particular direction.
  • Flux. Sets intensity based on lux (lx), an SI unit of illuminance.
  • Illuminance.Sets intensity based on foot-candles (fc), the American unit of illuminance. Specify a distance to use to calculate illuminance.
Color
Specifies the color of the light.
  • Color name. Specifies the name of the light color.
  • ?. Displays a list of color names.
  • Kelvin. Specifies the color based on a Kelvin temperature value.
Exit
Exits the Photometry prompt.

Shadow

Makes the light cast shadows.
Note: Starting with AutoCAD 2016-based products, shadows are always rendered no matter the current status or values of the Shadow option. This option is maintained for scripting and backwards compatibility.
Off
Turns off display and calculation of shadows for the light. Turning shadows off increases performance.
Sharp
Displays shadows with sharp edges. Use this option to increase performance.
Soft Mapped
Displays realistic shadows with soft edges.
  • Map Size. Specifies the amount of memory to use to calculate the shadow map.
  • Softness. Specifies the softness to use to calculate the shadow map.
Soft Sampled
Displays realistic shadows with softer shadows (penumbra) based on extended light sources.
  • Shape. Species the shape of the shadow (disk or rectangle) and its dimensions (radius or shape and width).
  • Samples. Specifies the size of the sample.
  • Visible. Specifies whether the shape of the shadow is visible.
  • Exit. Returns to the previous prompt.

Attenuation

Controls how light diminishes over distance. The farther away an object is from a spotlight, the darker the object appears. Attenuation is also known as decay.
Note: When the LIGHTINGUNITS system variable is set to 1 or 2, the Attenuation option has no affect on the light when rendered. This option is maintained for scripting and backwards compatibility.
Attenuation Type
Sets whether and how attenuation is displayed. The farther away an object is from a point light, the darker the object appears. Attenuation is also known as decay.
  • None. Sets no attenuation. Objects far from the spotlight are as bright as objects close to the light.
  • Inverse Linear. Sets attenuation to be the inverse of the linear distance from the light. For example, at a distance of 2 units, light is half as strong as at the spotlight; at a distance of 4 units, light is one quarter as strong. The default value for inverse linear is half the maximum intensity.
  • Inverse Squared. Sets attenuation to be the inverse of the square of the distance from the light. For example, at a distance of 2 units, light is one quarter as strong as at the spotlight; at a distance of 4 units, light is one sixteenth as strong.
Use Limits
Specifies whether to use limits.
Attenuation Start Limit
Specifies the point where light starts as an offset from the center of the light. The default is 0.
Attenuation End Limit
Specifies the point where light ends as an offset from the center of the light. No light is cast beyond this point. Setting an end limit increases performance where the effect of lighting is so minimal that the calculations are wasted processing time.

Color/Filter Color

Controls the color of the light.
True Color
Specifies a True Color. Enter in the format R,G,B (red, green, blue).
Index
Specifies an ACI (AutoCAD Color Index) color.
HSL
Specifies an HSL (hue, saturation, luminance) color.
Color Book
Specifies a color from a color book.

Exit

Exits the command.

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