Spotlight

Specify source position

Specifies the location of the light in 3D space:

• Pick a point in the drawing to position of the light
• Enter x,y,z coordinates
• Press Enter to accept the default location

Specify target position 

Specifies the location of the target, the point at which the spotlight is focussed:

• Pick a point in the drawing to position of the target
• Enter x,y,z coordinates
• Press Enter to accept the default location

Name

Specifies a name for the spotlight; prompts you:

Enter light name <Spotlight1> - (enter a name or press Enter to accept the default name.)

Intensity or Intensity factor

Specifies the intensity of the light; prompts you:

Enter intensity (0.00 - max float) <1.0> - (enter an option:)

• Enter an intensity values between 0.00 and the maximum value supported by your system (max float = maximum value of a floating point number)
• Press Enter to accept the default value

When LightingUnits variable is 0, this option is named Intensity; when 1 or 2, Intensity factor.

Status

Toggles the use of this light; prompts you:

Enter status [ON/OFf] <ON> - (enter an option:)

• ON - light is included when calculating renderings
• OFf - light is excluded

Hotspot

Enter hotspot angle (0.00-160.00) <45.0>: (Enter a value between 0.00 degrees and 160.00 degrees).

Enter falloff angle (0.00-160.00) <50.0>: (Enter a value between 0.00 degrees and 160.00 degrees). If yout enter a Falloff angle that is smaller than the Hotspot angle, the latter is set equal to the Falloff angle.

When a surface is illuminated by a spotlight, there is an area of maximum illumination (hotspot) that is surrounded by an area of lesser intensity (falloff).

• Hotspot angle: angle of the central light cone (defines the hotspot)

• Falloff angle: angle of the full light cone

The difference between the hotspot angle and the falloff angle defines the area of lesser light intensity. If the falloff angle and the hotspot angle are almost equal the edge of light cone is rather sharp. The greater the difference between both angles, the softer the edge of the light cone.

Photometry

(This option is available only when LightingUnits is 1 or 2.) Specifies the photometric properties of the light; prompts you:

Enter a photometric option to change [Intensity/Color/eXit] <Intensity> - (enter an option:)

• Enter intensity (Cd) or enter an option [Flux/Illuminance] <1500.0>: - (enter the intensity expressed in candela or an option:)
  Enter Flux (Lm) - (enter the luminous flux expressed in lumens.)
  Enter Illuminance (Lx or Fc) or enter an option [Distance] <9424.8> - (enter the illuminance expressed in lux or foot-candles.)
  Enter Distance - (Enter a distance expressed in drawing units.)

• Enter color name or enter an option [?/Kelvin] <D65> - (enter a color name .)
  ? - lists the names of available colors, such as:
        D65
        Fluorescent
        Coolwhite
        Whitefluorescent
        daylightfluorescenT
        Incandescent
        Xenon
        Halogen
        Quartz
        Metalhalide
        mErcury
        Phosphormercury
        highpressureSodium
        Lowpressuresodium
  
  Enter Kelvin temperature <3600.0> - (enter a color temperature expressed in degrees Kelvin.)

Hotspot

Specifies the angle of the hotspot, the area of light concentration; the angle determines the size of the hotspot, irregardless the distance of  target. Prompts you:

Enter hotspot angle (0.00-160.00) <45> - (enter an angle, or press Enter to accept the default)

Falloff

Specifies the the angle of weaker illuminations surrounding the hotspot; out side of the falloff, there is no light. Prompts you:

Enter falloff angle (0.00-160.00) <50> - (enter an angle, or press Enter to accept the default.)

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:)

• Off - disables the calculation of shadows for the light.

• Sharp - displays shadows with sharp edges. Use this option to increase performance.

• Soft mapped - displays realistic shadows with soft edges.
  Prompts you: Enter map size [64/128/256/512/1024/2048/4096] <256>:

• Soft sampled : Displays realistic shadows with softer shadows based on extended light sources; prompts you:
  Enter an option to change Shape/sAmples/Visible/<eXit> - (enter an option:)
      Enter shape [Disk/Rect] <Disk> - (type D or R)
      Enter radius <0.0> - (enter the radius of the disk)
      Enter Width <0.0> - (enter width of the rectangle)
      Enter Length <0.0> - (enter length of the rectangle)

• Enter Shadow Sample <16> - (specify the sampling size of the shadow); larger numbers are more accurate but take longer to render.

• Enter Shape Visibility [Yes/No] <No> - (type Y or N to cast a shadow that represents shapes (more accurate) or is rectangular (faster to render).)

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:)

• Enter attenuation type [None/Inverse linear/inverse Squared] <None> - specifies the type of attenuation:
    None -  No attenuation so that the distance to the light source has no influence
    Inverse linear - attenuation is the inverse of the linear distance from the light: at a distance of 2 units from the light source, light is half as strong; at a distance of 4 units, light is one quarter as strong
    Inverse squared - attenuation is the inverse of the square of the distance from the light: at a distance of 2 units, light is one quarter as strong; at a distance of 4 units, light is one sixteenth as strong
  
• Use limits - toggles whether the extent of the illumination is limited; prompts you:
    Limits [OFf/ON] - (enter an option:)
      ON - limit the extent
      OFf - do not limit it
  
  
• attenuation start Limit - defines the point where the light starts to shine, measured from the center of the light; prompts you:
    Specify start limit offset <1.0> - (enter a distance.)

• attenuation End limit - defines the point where the light stops to shine, measured from the center of the light; prompts you:
    Specify end limit offset <10.0> - (enter a distance.)

Color or filterColor

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:)

• Enter true color - the RGB color model is an additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue. The component values are stored as integer numbers in the range 0 to 255, the range that a single 8-bit byte can offer (by encoding 256 distinct values).

• Index color - specifies an AutoCAD Color Index color.

• Hsl - specifies the color using three parameters Hue, Saturation and Lightness

When LightingUnits variable is 0, this option is named Color; when 1 or 2, filterColor.

Exit

Concludes the command and creates the light.