Distantlight command in AutoCAD – Create the distant light source

1. The way to start Distantlight command in AutoCAD.

Distantlight command helps us to create the distant light source.

Distantlight

Specify light direction FROM <0,0,0> or [Vector]: Choose the start point of light direction or enter V.
Specify light direction TO <1,1,1>: Choose the end point of light direction

If enter option Vector, the below prompt line appears:

Specify vector direction <0.0000,-0.0100,1.0000>: Enter coordinates of vector direction.

After you define the light direction and if variable of system LIGHTINGUNITS is set up equal 0, the below prompt line appears:

Enter an option to change [Name/Intensity/Status/shadoW/Color/eXit] <eXit>: Enter an option to change

If system variable LIGHTINGUNITS is set up equal 1 or 2, the below prompt line appears:

Enter an option to change [Name/Intensity factor/Status/Photometry/shadoW/ filterColor/ eXit] <eXit>: Enter an option to change

Note:
When system variable LIGHTINGUNITS is set up equal 1 or 2, the option Attenuation does not affect in creating the light source.

Distantlight command in AutoCAD – Create the distant light source

2. The options with Distantlight command

Name

Enter the name of light source with capital letter and normal letter, numbers, space, hyphens, underscores. The maximum of length is 256 characters.

Enter light name: Enter name of light source
Intensity/Intensity Factor

Set up intensity or brightness of light. The value range from 0.00 to the maximum value is supplied by your system. When the light intensity is equal 0, the light source is turned off.

Enter intensity (0.00-max float) <1.0000>: Enter the value of light intensity.
Status

Turn on or turn off the light source: Enter N to turn on, enter F to turn off.

Enter status [on/onf] <On>:
Photometry

Photometry is the measure of luminous intensity of the visible light sources. Photometry appears when variable of system LIGHTINGUNITS is set up equal 1 or 2.

At photometry, luminous intensity is the measure of visible energy which is shined by a light source with a determined direction. Luminous flux is the visible energy of each unit of solid angle. The whole luminous energy with a light bulb is the visible energy which is shined to all directions. The brightness is the whole luminous energy on a surface, each unit of area.

Enter a photometric option to change [Intensity/Color/eXit] <I>: Enter an option to change.
Intensity

Distantlight command in AutoCAD – Create the distant light source

Enter intensity (Cd) or enter an option [Flux/Illuminance] <1500.0000>: Enter value of light intensity.

Enter a value unit of light intensity according to Candela, visible energy according to value of luminous flux or value of illuminance with the whole luminous flux on a surface.

Candela (symbol: cd): is the unit of luminous intensity SI (visible energy is shined by a light source with a determined direction)
Lux (symbol: lx) is the unit of illuminance SI.
Foot-candle (symbol: fc) is the unit of American illuminance
Enter F to define the visible energy according to the value of luminous flux.

Enter Flux (Lm) <18849.5556>: Enter the value of luminous flux

- If you enter I, you can define the light intensity basing on the value of illuminance

Enter Illuminance (“Lx”|”Fc”) or enter an option [Distance] <1500.0000>: Enter the value of illuminance

The value of illuminance can be defined following to lux or foot-candles. Enter D to define the distance to calculate the illuminance.

Enter Distance <1.0000>: Enter the distance.
Enter color name or enter an option [?/Kelvin] <D65White>: Enter color name or enter an option

Distantlight command in AutoCAD – Create the distant light source

You define the color of light source basing on color name or Kelvin temperature. Enter ? to display a list of color names.

Enter color name(s) to list <*>: Enter color name.

Enter a string of characters which uses representative characters (wild card characters) to display the list of color names or enter asterisk (*) to display all options.

If you enter K, you can define the color of light basing on the value of Kelvin temperature.

Enter Kelvin temperature <3600.0000>: Enter Kelvin temperature.
Exit: Escape the option of the command.

Shadow

Create shadow

Enter shadow settings [Off/Sharp/soFtmapped/softsAmpled] <Sharp>:

Off Turn off shadow.

Sharp Display shadow with sharp edges.

Soft Mapped Display realistic shape with soft edges.

Enter map size [64/128/256/512/1024/2048/4096] <256>: Enter the size of memory system to calculate the shadow.
Enter softness (1-10) <1>: Enter the softness to calculate the shadow.

Soft Sampled

Display realistic shape with soft shadow (penumbra) basing on the long light source.

Enter an option to change [Shape/sAmples/Visible/eXit]<eXit>: Enter an option to change
Enter S to define the shape of shadow and dimensions of the shape. (For example: Radius of sphere or length and width of a rectangle)

Enter shape [Linear, Disk, Rect, Sphere,Cylinder] <Sphere>: Enter shape.

Enter A to define the dimension of shadow sample.

Enter Shadow Sample <16.0000>:

Enter V to define the visible ability of shadow shape.

Enter Shape Visibility [Yes/No]<No>:

Distantlight command in AutoCAD – Create the distant light source

Color/Filter Color

Control the color of light.

Enter true color (R,G,B) or enter an option [Index color/Hsl/colorBook] <255,255,255>:
True Color : Define True color, enter according to format R,G,B (red, green, blue).
Index: Define color ACI (AutoCAD Color Index)

Enter color name or number (1-255): Enter the color name or number

HSL: Define color HSL (hue, saturation, luminance).

Enter HSL color (H,S,L) <0,0,100>:

Color Book: Define color from color book.

Enter Color Book name: Enter Color book name

Exit: Exit the command.

Create the Distant light source

1. Enter command Lightingunits and set up the value equal 0 for standard lighting.

2. Click View menu Render Light New Distant Light. Enter command Distantlight.

3. Click to choose the position of light source FROM: P1

4. Choose a position for light direction TO: P2

5. Enter N at the prompt line of command and enter the name. This name will appear in the characteristics.

6. (properties) and in the window Lights in Model when starting the command

7. Press ENTER to exit the command.

Distantlight command in AutoCAD – Create the distant light source

To change the characteristics of distant light, you enter the command Lightlist. In the window Lights in Model, click double on the name of distant light from the light list and use the board Lighting-Properties to change the color and its other different characteristics.

Using the Distant Lights

Distant lights is used to shine the objects or backdrop barrier.

Distant Lights according to Standard Lighting Workflow

Distant light shines the parallel same light rays following to a direction (picture 12.16). You can define the start point P1 (FROM point) and the end point P2 (TO point) at any place in the viewport to define the light direction. With the Spotlights and point lights, each type is performed by a different light glyph. Distant lights and the sun are not performed by glyphs in the drawing because they do not have the determined position and effect on the whole view. The intensity of distant light does not reduce following to the distance.

Distant Lights according to Photometric Workflow

Distant Lights is not exact following to the laws of nature. Therefore, we do not use it in photometric workflow.