RedSDK Directional Luminance

RedSDK Directional Light Luminance

About Directional light

A Directional light shines a along a path defined by Dir. and with shadows unticked it continues infinitely in that direction and returns back onto itself, (like it goes around the world), it is also an infinitely wide light irrespective of the size of the source object.

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Parameters

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  • Intensity – Set the intensity of the light.
As the name suggests it alters how bright the light will shine, this should be adjusted in conjunction with the diffuse affect as one affects the other, in the images below, the left picture is intensity =1 the right has intensity = 5, NOTE shadows box is un-selected.

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  • Diffuse color – Sets the diffuse color of the light.
  • Diffuse affect – Sets the relative intensity (power) of the diffused light.
The majority of the time one would leave Diffuse colour at a grey colour, however changing to another colour can produce unusual effects, Diffuse Affect is used to increase / decrease the intensity of the colour, moving the sliders to the left decreases the colour affect, to the right increases the colour affect.

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  • Specular color – Sets the specular color of the light.
  • Specular affect – Sets the relative intensity (power) of the Specular light.
The Specular effect is used on pen / brush coloured objects when no materials have been applied, specular is over-ridden by material settings and will not show up.

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  • Pos – Sets the X,Y,Z position of the light relative to the object to which it is attached.
Because of the way directional light illuminates all objects in a given direction, the position of the light is of little use, suggest leaving this as 0,0,0.

  • Dir – Sets the X,Y,Z direction of the light relative to the position.
As the title states it alters the direction of the light with respect to the source objects x,y,z axes, but because of the properties of the directional lights, it in mainly noticeable on shadows at anything other than 90 degrees (a value of 1).

Adding a value of 1 in a single input box (x, y or z) relates to the direction of the light, adding a second value in another input box rotates the light, below right, 0.1 was added to the 'x' direction 'z' was left as 1.

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  • Top – Defines a second axis which is perpendicular to the direction, used for the rotation, if the lights display is not circular.
Because of the way directional lights work, the light is shape-less, leave this set at 0,1,0 as found or 0,0,0

  • Shadows – Sets whether the light will generate shadows, or not.
  • Shadow Color – Specifies the color of shadows created by the light.
Shadow colour would normally be left at a grey scale colour (black to white), and moving the slider towards the right (towards white)will lighten the shadows, moving left (towards black)darkens the shadows.

Changes the colour of the shadow for example to blue, produces variation in the colour depending of the colur / material of the object on which the shadow falls, which is more prominent on white objects as shown below.

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In theory - the Shadow map selector should switch on the use of automatic shadow map generation, which can make rendering a little quicker at a slight cost in shadow quality, However, according to RedSDK documentation, shadow maps are not supported with directional light, so selecting this may not make any difference to the render.


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Contributors to this page: AndyUK .
Page last modified on Saturday 04 of February, 2017 02:44:18 PST by AndyUK.