Hi there!

Any idea how one can create a realistically looking blue-ish haze 
affecting far-away objects? I've been fiddling around for a while trying 
various kinds of scattering media - with the effect that the sky_sphere 
virtually always turned completely white.

Thank you in advance -

	Torsten

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In article <3f01b1f7$1@news.povray.org>,
 Torsten Crass <tor### [at] eBiologyde> wrote:

> Any idea how one can create a realistically looking blue-ish haze 
> affecting far-away objects? I've been fiddling around for a while trying 
> various kinds of scattering media - with the effect that the sky_sphere 
> virtually always turned completely white.

    The sky_sphere feature just provides a background. It is considered 
to be infinitely distant, which gives you an infinite amount of media in 
front of it. Try putting your media in a container that simulates an 
actual atmosphere.

    Since you are just doing atmospheric haze, you might find fog easier 
to control and faster to render. It is far less flexible and less 
accurate, but much faster. You won't see light and shadows in it, so it 
isn't good for dense fog, but it should be fine for an even haze.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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If you want to use media, try the following,

-use a container object for the media: this will allow you to control the
depth of the haze and I think it is faster than uncontained media.

- discard the sky_sphere: if the media is properly scaled it should not only
give a blueish cast to distant (dark) objects, but also provide the blue sky
color (against a black background). Here is where a container object can be
useful - a small media "depth" overhead and a greater "depth" at the horizon
can provide a nice color gradient.

- try using method 2 if you can get away with it, an set the sampling as low
as possible while still retaining image quality.

- also remember, lighter objects will generally tend towards red instead of
blue with distance. Absorption media would work here.

Abe




"Torsten Crass" <tor### [at] eBiologyde> wrote in message
news:3f01b1f7$1@news.povray.org...
> Hi there!
>
> Any idea how one can create a realistically looking blue-ish haze
> affecting far-away objects? I've been fiddling around for a while trying
> various kinds of scattering media - with the effect that the sky_sphere
> virtually always turned completely white.
>
> Thank you in advance -
>
> Torsten
>

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Hi Chris, hi Abe!

Thanks a lot for your advice - I tried both a scattering medium 
constrained by a (large) object as well as ground fog. After tuning all 
parameters, I got nice looking results with both methods, but since fog 
really renders much faster I think I'll go for this solution.

Thanks again, and happy raytracing -

	Torsten

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