RedSDK Beam Light Luminance
About Beam LightA Beam light creates a beam of infinite length which can pass through objects, as can be seen from the white dots as shown below.
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.
- Intensity decay â€“ This Set the rate at which the lights power diminishes with distance.
- Diffuse color â€“ Sets the diffuse colour of the light.
- Diffuse affect â€“ Sets the relative intensity (power) of the diffused light.
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.
- Specular color â€“ Sets the specular color of the light.
- Specular affect â€“ Sets the relative intensity (power) of the Specular light.
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,
- Pos â€“ 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.
- Dir â€“ Sets the X,Y,Z direction of the light relative to the position.
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,
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.
- Top â€“ Defines a second axis which is perpendicular to the direction used for the rotation if the lights display is not circular.
- Inner Radius â€“ Sets the inner radius for the light.
- Outer Radius â€“ Sets the outer radius for the light.
- Shadows â€“ Sets whether the light will generate shadows or not.
- Shadow Color â€“ Specifies the color of shadows created by the light.
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.
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.
- Shadow Map â€“ 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 â€“ Sets the resolution of the shadow map. Values must be a multiples of 2.
- Shadow Map Blur â€“ Sets a blur factor on the shadow map, reducing jagged edges and transitions.
The pictures below shows the shadow variation at different resolutions.
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.
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.
When set to No Decay, Increasing the intensity increases the brightness of the light.
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RedSDK Luminance Reference