Creates a point light for use in renderings, placing this glyph in the drawing:
Note: A point light spreads illumination in all directions, like a bare lightbulb, and so has no target.
Accessing the Command
command bar: pointlight
menu bar: View | Rendering | Lights | New point light
ribbon: View | Lights | Create | New Point Light
toolbar: Lights |
: Pointlight
Prompts you in the command bar:
Specify source position <0,0,0>: (Specify the position of the light)
- When the LIGHTINGUNITS system variable is 0 (no lighting units), the following prompt displays:
Enter an option to change [Name/Intensity/Status/shadoW/Attenuation/Color/eXit] <eXit>: (Enter an option,or press Enter to end the command)
- If the LIGHTINGUNITS system variable is 1 (American lighting units) or 2 (international lighting units), the following prompt displays:
Enter an option to change [Name/Intensity factor/ Status/ Photometry/ shadoW/ Attenuation /filterColor/ eXit] <eXit>: (Enter an option,or press Enter to end the command)
Command Options
Option |
Description |
Specify source position |
Specifies the position of the light:
|
Name |
Specifies a name for the light so that it can be identified by the LightList command; prompts you: Enter light name <Pointlight1> - (enter an option):
|
Intensity Factor Intensity |
Specifies the intensity of the light; prompts you: Enter intensity (0.00 - max float) <1.0> - (enter an option):
|
Status |
Toggles the use of this light; prompts you: Enter status [ON/OFf] <ON> - (enter an option):
|
Photometry |
Specifies the photometric properties of the light; prompts you: Enter a photometric option to change [Intensity/Color/eXit] <Intensity> - (enter an option):
|
Shadow |
Specifies the look of shadows cast by this light; prompts you: Enter shadow settings [Off/Sharp/soFt mapped/soft sAmpled] <Sharp> - (enter an option):
|
Attenuation |
Specifies how the illumination falls off with distance from the light: Enter an option to change [attenuation Type/Use limits/attenuation start Limit/attenuation End limit/eXit] <eXit> - (enter an option):
|
colorFilter |
Specifies the color of the light; prompts you: Enter true color (R,G,B) or enter an option [Index color/Hsl]:<255,255,255> - (enter an option):
|
eXit |
Concludes the command and creates the light. |
Definitions
Candela
The candela (symbol: cd) is the SI base unit of luminous intensity; that is, power emitted by a light source in a particular direction, weighted by the luminosity function (a standardized model of the sensitivity of the human eye to different wavelengths, also known as the luminous efficiency function). A common candle emits light with a luminous intensity of roughly one candela.
Lumen
The lumen (symbol: Lm) is the SI unit of luminous flux, a measure of the power of light perceived by the human eye. Luminous flux differs from radiant flux in that luminous flux measurements (such as lumens) are intended to reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux measurements (such as watts) indicate the total power of light emitted. The lumen is defined in relation to the candela as: 1 lm = 1 cd·sr
As a full sphere has a solid angle of 4·pi steradians, a light source that uniformly radiates one candela in all directions has a total luminous flux of 1 cd·4pi sr = 4pi ≈ 12.57 lumens. For example, if a candle emits light with a luminous intensity of about 1 candela, the total light emitted is about 12.6 lumens.
Illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with human brightness perception.
LIGHTINGUNITS=2
International lighting units uses SI units derived units illuminance is measured in lux (lx) or lumens per square metre.
LIGHTINGUNITS=1
American lighting units use the foot-candle (Fc) is a non-metric unit of illuminance that is used in photography. The unit is defined as the amount of illumination the inside surface of a 1-foot radius sphere would be receiving if there were a uniform point source of one candela in the exact center of the sphere. Alternatively, it can be defined as the illuminance on a 1-square foot surface of which there is a uniformly distributed flux of one lumen. This can be thought of as the amount of light that actually falls on a given surface. The foot-candle is equal to one lumen per square foot. One foot-candle is equal to approximately 10.764 lux, although in the lighting industry, typically this is approximated as 1 foot-candle being equal to 10 lux.
Kelvin Temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that light source. The temperature is conventionally stated in units of absolute temperature: degrees kelvin (K).
Higher color temperatures (5,000 K or more) are called cool colors (blueish white); lower color temperatures (2,700 – 3,000 K) are called warm colors (yellowish white through red).
Related Commands
Distantlight - creates a distant light.
Light - creates a new light in the drawing.
Lightlist - displays the Drawing Explorer - Lights dialog window.
Render - calculates a photorealistic image of the 3D model.
Spotlight - creates a spot light.
Sunproperties - displays the Sun Properties of the Active Viewport editor in the Drawing Explorer - Lights dialog.
Weblight - creates a web light.