Any number of atmospheric effects may be associated with the default
medium (``air'').
- <#4948#><#4948#>
- <#1443#>fog<#1443#> #math142##tex2html_wrap_inline4950# #math143##tex2html_wrap_inline4952#
Add exponential fog with the specified <#606#>thinness<#606#> and <#607#>color<#607#>.
Fog is simulated by blending the color of the fog with the color of
each ray. The amount of fog color blended into a ray color is an exponential
function of the distance from the ray origin to the point of intersection
divided by the specified <#609#>thinness<#609#> for each color channel.
If the distance is equal to <#610#>thinness<#610#>,
a ray's new color will be half of the fog color plus half its
original color.
- <#4953#><#4953#>
- <#1448#>mist<#1448#> #math144##tex2html_wrap_inline4955# #math145##tex2html_wrap_inline4957# <#1451#>zero scale<#1451#>
Add global low-altitude mist of the specified color. The color of
a ray is modulated by a fog with density that varies linearly with
the difference in z coordinate6.1between the ray origin and
the point of intersection. The thinness values specify the transmissivity
of the fog for each color channel.
The base altitude of the
mist is given by <#617#>zero<#617#>, and the apparent height of the mist can
be modulated using <#618#>scale<#618#>, which scales the difference in
altitude used to compute the fog.
- <#4961#><#4961#>
- <#1454#>fogdeck<#1454#> <#1455#>altitude<#1455#> <#1456#>offset<#1456#> #math146##tex2html_wrap_inline4963# <#1458#>chaoscale<#1458#>
#math147##tex2html_wrap_inline4965# #math148##tex2html_wrap_inline4967#
Add low-altitude fog, with transmissivity modulated by
a chaotic function.