RedSDK Beam Luminance

RedSDK Beam Light Luminance

About Beam Light

A Beam light creates a beam of infinite length which can pass through objects, as can be seen from the white dots as shown below.

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The beam is held in check by use of the shadow tick box (with limitations), or by using the Intensity decay, it is defined by an inner and outer radius with the inner being bright and the light decaying to the outer radius.

PARAMETERS

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  • Intensity decay – This Set the rate at which the lights power diminishes with distance.
See separate intensity decay page for description of each option.
  • Diffuse color – Sets the diffuse colour 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 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.

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When using a non grey colour, the diffuse colour midpoint of the slider is the selected colour, again moving the slider left or right, darkens or lightens the beam.
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  • Specular color – Sets the specular color of the light.
  • Specular affect – Sets the relative intensity (power) of the Specular light.
Specular works on pen coloured objects only, i.e. objects with no material attached, and is ignored when materials are applied to the object, the specular affect alters the amount of light (shiny area) on a curved object.

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Specular colour will vary in the effect depending on the objects pen colour and the affect slider, in some cases the effect of specular colour can be subtle or non existent,

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  • Pos – This Sets the X,Y,Z position of the light relative to the objects being used as the luminance source, it sets the source position where 0,0,0 = the centre of extents of the object, this needs to be remembered if the source object is a box, sphere etc. but not a concern if the source is a flat sheet object.
The example below has the source object as a sphere of 330 units diameter (115 units radius), leaving the position at 0,0,0 will include the sphere in the rendered beam.

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  • Dir – Sets the X,Y,Z direction of the light relative to the position.
Dir determines the direction where the light will be pointing relative to the source object extents axes, in the examples above, the source objects 'Z' axes is pointing towards the lights destination, therefore Dir is set as 0,0,1.

In the example below, the luminance source is a black sphere, the current beam is set at direction 0,0,1 (the 1 = +z), to point towards the kettle,

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The toaster is 45 degrees from the source axes, therefore lies at +Z and in the -X direction, +Z is already at 1, therefore for a 45 degree angle, X must set as, X = -1, as can be seen below it is input into the Dir row, and the resultant beam is angled accordingly.

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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.
There would be few occasions when this would be needed as a beam light is a circular light irrespective of the source object shape,

  • Inner Radius – Sets the inner radius for the light.
  • Outer Radius – Sets the outer radius for the light.
The radius has two sections, The inner radius defines the bright spot, the light then decrease between inner and outer, with no light beyond outer radius,

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  • Shadows – Sets whether the light will generate shadows or not.
  • Shadow Color – Specifies the color of shadows created by the light.
in most circumstances the shadow colour would be left at grey scale (black to white), the shadow colour has the effect of muting the beam light after is passes through an object

As can be seen below, on the left shadows was not selected, resultin in the beam being constant as it passes through the objects, on the right, shadows is selected and shadow color slider midway, the beam / shadows are muted as they pass trough objects.

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Below left, the shadow colour is set to black, the beam will still pass through, but the black shadow cast by objects / walls means the beam is no longer visible, on the right the shadow colour was set to yellow, which can create unusual effects.

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  • Shadow Map – Shadow maps are generated by testing whether or not each specific pixel is visible from the light source. This accomplished by comparing each pixel to a depth image (z-buffer) of the light source's view, stored in the form of a texture file. Shadow maps can accelerate the rendering of shadows, but usually as the cost of some quality.
  • Shadow Map Resolution – Sets the resolution of the shadow map. Values must be a multiples of 2.
  • Shadow Map Blur – Sets a blur factor on the shadow map, reducing jagged edges and transitions.
Because shadow map compares depth map pixels rather than computing each pixel from the light source at render time, shadow maps can be faster that other render modes, however the resolution of the depth map plays an important part in how the shadows appear, if the shadow resolution is too low the shadow can be pixelated, however increasing the resolution too high can be a little slower to render

The pictures below shows the shadow variation at different resolutions.

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One last Shadow setting is blur, this has the effect of smoothing out the edges, the effect will vary depending on the shadow resolution, as can be seen below.

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The final setting for the Beam light is Intensity, this is accessed by clicking the '+' sign against the light within the render manager.

NOTE. The decay page will vary depending on which Intensity Decay has been set,
See RedSDK Intensity Decay page for options.

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When set to No Decay, Increasing the intensity increases the brightness of the light.

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Previous page - RedSDK Ambient Luminance
Next Page - RedSDK Directional Luminance

Links
Wiki Homepage
RedSDK Luminance Reference


Contributors to this page: AndyUK .
Page last modified on Sunday 05 of March, 2017 11:21:41 PST by AndyUK.