Rough Guide to the Atmopshere Editor – Part 4 – Lighting Models 2

This fourth part will cover the remainder of the settings from the Light tab as the first part would be too long otherwise. For the first part of this guide the default spectral model will be used. There will be an inclusion of a cone and a cube as shown in the render below. All renders are at 800×600 on the “broadcast” quality setting.

Global Light Adjustment

Light Intensity
This value affects the strenght of the light in the scene, its similar to contrast in a way, except not quite as simple. Consider it the effect of chanigng a 40w bulb with a 100w bulb.

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Light balance
The light balance slider determines where the light comes from, wether it is ambient i.e. coming from the sky dome, or coming from the sunlight. higher values relate to more sunlight, lower values relate to more skylight.

This value works well when it is correlated with the other two settings, i.e. more ambience goes with a brighter light intensity, more sunlight a lower intensity.

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100%

Ambient Light
Ambient Light affects where the light is coming from in a scene.

lets you further customize ambient light by deciding how it is shared between light coming from the sky, and light coming from everywhere (uniform light). Scenes with fog will usually require larger amounts of uniform ambient light, whereas scenes with a bright sky will have lots of light coming from the sky

The differences noticeable in this scene are very slim, I will later retry with a foggy scene.

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Light Colour
This colour affects the colour of the light and is cumulative with the colour of the sunlight. This detail can only be changed in Standard, Volumetric and Environmental mapping.

Light color acts as a filter for the color of the lights in your scene. Having an orange light color, with a sun color that is green will make the light coming from the sun a darker shade of green. It is a natural phenomenon that sunlight gets warmer (i.e. takes yellow to orange shades) as the sun gets closer to the horizon. Such warm lights can yield pleasing results when exposed objects take on warm shades.

This is the default colour in the default scene.

The scene can be made much warmer with a slightly darker yellow colour..

or a lot colder with a grayish blue.

This setting probably works better with other settings tweaked too, as most of them will…

Ambient Light Colour
Ambient light colour changes the colour of the general sky area and thus affects the light that is radiated to the objects in the scene.

when the ambient colour is changed to a deep grey blue (56.67,111) it takes on a much colder, sharper feel.

Whereas with an orange (185,128,55) it takes on a much warmer feeling, the skyline feels more polluted in this case (to my eyes..)

Apply Settings
These options allow you to use the changes you made to the above options in a variety of different ways.

To all lights
Affects all lights in the scene.

Only to sunlight
Affects the colour of the sunlight

To sky and clouds.
Affects the Colour of the sky and the clouds.

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The following settings only apply to volumetric, standard and environmental models of atmosphere as spectral models do this automatically.

Autodecay Sunlight Colour
This setting is not available in the spectral model becuase it is automatically calculated.

The options in this group control the way the color of light reddens as it gets closer to the horizon.

The manual states that this option should be turned off for the volumetric models. The examples below are in the standard model with the option turned on and off.

On

Off

Light Decay Colour
The light decay colour determines what colour the sky decay has and what colour the light will decay too, in the following example the decay is set to 218,171,71.

in the following example, it has been changed to a deep red 144,38,41.

note how the ambience from the light has become much redder, with a dark blue hue, the scene becomes much colder.

Decay Amount
Decay amount determines how much the light decays. The larger the value the darker the scene as less light rays are able to reach the objects.

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Decay Rate
Decay rate determines how quickly the decay occurs, the higher the value the quicker it decays.

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Thats all for part 4, hope it helps

Part 5 is now out!