[Radiance-general] Using MIST for overcast sky

[pillo.pillo at tin.it]

ERRATA CORRIGE
apparently -ds doesn't do the trick of subdividing the source for the mist...
if you are simulating light from windows this shouldn't be an issue
but if you have an open volume of atmosphere you may see bright areas of
mist in corrispondence of the sources centres (depending on your mist settings).

I guess the reason is that it is more efficient to only test the centre
as usually sources are small compared to the scene dimensions... in your
case it is the opposite... 
any ideas how to solve this (a part using tons of small sources)?

giulio

>-- Messaggio originale --
>From: Giulio Antonutto <Giulio.Antonutto at arup.com>
>To: 'Radiance general discussion' <radiance-general at radiance-online.org>
>Subject: RE: [Radiance-general] Using MIST for  overcast sky
>Date: Fri, 16 Apr 2004 14:56:43 +0100
>Reply-To: Radiance general discussion <radiance-general at radiance-online.org>
>
>
>hi,
>glow is considered as a light source by the direct component only within
>the
>given distance (4th number of glow definition) and I guess "mist" doesn't
>consider glow with 0 (or -1) because it is not a direct light source.
> 
>a quick and probably useless (**) trick is to change the sky description
>
> 
>from
>skyfunc glow skyglow
>0
>0
>3 1 1  1
>to
> 
>skyfunc light skyglow
>0
>0
>3 1 1  1
> 
>this way the 1st bounce is now direct but -ds doesn't work on the sky and
>there is just a big point source above so ...  (**) 
> 
>another trick (this time should be ok) is to create a big polygonal volume
>of brightfunc-light-sources with the sky distribution... in this case you
>could be able to use -ds.
> 
>hope it helps,
> 
>giulio
> 
>-----Original Message-----
>From: radiance-general-bounces at radiance-online.org
>[mailto:radiance-general-bounces at radiance-online.org]On Behalf Of Guedi
>Capeluto
>Sent: 16 April 2004 10:07
>To: radiance-general at radiance-online.org
>Subject: [Radiance-general] Using MIST for overcast sky
>
>
>Hi,
> 
>I am trying to simulate the extinction of light inside a MIST volume, for
>different sky conditions.
>The simulations seems to work well using "sun" as the light source, but
I
>have problems when using an overcast sky or a sunny sky with no sun (-s
>option).
>The light sources for the MIST volume are "sun" and "sky" which is defined
>using glow.
>Did MIST work for glow type light sources? If not, what do you recommend
>to
>use to simulate this case, with diffuse light coming from the sky?
> 
>Thank you in advance,
> 
>Guedi
>--- 
>Arch. Guedi Capeluto, D.Sc.
>Faculty of Architecture and Town Planning
>Technion - Israel Institute of Technology
>Technion City, Haifa 32000. Israel.
>Tel: +972.4.8294013    Fax: +972.4.8294617
>email: arrguedi at tx.technion.ac.il
> 
>
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