RedSDK Rect Area Luminance

RedSDK Rectangular Area Light Luminance

About Rectangular Area Light

Area light sources are surface lights that emit light from a rectangle.



  • Intensity decay – Set the rate at which the lights power diminishes.
See Separate RedSDK intensity Decay page.


  • Diffuse color – Sets the diffuse color of the light.
  • Diffuse affect – Sets the relative intensity (power) of the diffused light.
Diffuse colour and affect, do a similar job in black to white colour, the colour will most often be left at grey scale (black to white), moving the colour slider toward the left (black) darkens the beam, moving towards the right (white) brightens the beam, equally moving the 'affect' slider towards '0' darkens the beam, towards 100 brightens the beam,


  • Specular color – Sets the specular color of the light.
  • Specular affect – Sets the relative intensity (power) of the Specular light.
Specular colour and affect works with pen colour when no material is applied, it is overridden when a material is applied to a object.
Specular is particularly effective in draft render mode, with no materials applied, just pen colour.
  • Pos – Sets the X,Y,Z position of the light relative to the object to which it is attached.
Position is used to move the light away from the source object, for example if the source is a fixed object that cannot be moved.


  • Dir – Sets the X,Y,Z direction of the light relative to the position.
DIR can be used to alter the direction of the light but Dir and Top should not be the same, setting two values will cause the light to angle..


  • Top – Defines a second axis which is perpendicular to the direction, used for the rotation if the lights display is not circular.
  • Samples Count – Sets the number of samples used to populate the light surface. Must be greater than 0.

  • Width – Sets the width of the defining rectangle.
  • Height – Sets the height of the defining rectangle.


  • Shadows – Sets whether the light will generate shadows, or not.
  • Shadow Color – Specifies the color of shadows created by the light.
The shadow colour has two functions, to change the colour of the shadow and to lighten and darken the shadow, on most occasions the colour will be left grey, moving the slider towards the left (black) will darken the shadow, moving towards the right (white) will lighten the shadows


  • Shadow Map - Sets whether shadow map will be used.
There are no user controls with this shadow map, it appears fully automatic, Shadow maps cap speed up rendering by taking an image (map) from the lights perspective and re-rendering from the camera comparing each pixel to the map, however they can result in a slight loss of quality, and may be unsatisfactory for use with glass objects.


  • Intensity or Decay - clicking the plus sign next to the luminance name will allow selecting of either Intensity (if no decay is set), or the decay name and decay parameters, see RedSDK Intensity Decay page.


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Contributors to this page: AndyUK .
Page last modified on Tuesday 07 of March, 2017 05:03:49 PST by AndyUK.