[Radiance-general] RE: Using MIST for overcast sky

[Guedi Capeluto]

Thanks Greg,

Our intention is to simulate light extinction inside a tree (yes yes...a
tree) or a group of trees with the purpose of studying light penetration
according to different morphologies. The mist approach looked to me much
simpler than modeling the whole tree (or a lot of trees), considering than
even in this case the model will be just an approximation.

Anyway I will try constructing a dome from polygons
brightfunc-light-sources, as Giulio suggested.

Guedi







-----Original Message-----
From: Greg Ward [mailto:gward at lmi.net]
Sent: Monday, April 19, 2004 1:30 AM
To: Guedi Capeluto; Radiance general discussion
Cc: pillo.pillo at tin.it
Subject: Re: Using MIST for overcast sky

Hi Guedi,

Well, then you can try Pillo's suggestion of simulating the sky as many
small sources, but I don't hold out much hope that you'll get an
accurate answer.  What local phenomenon are you trying to simulate,
exactly?  A puff of smoke?

-Greg

Begin forwarded message:

> From: "Guedi Capeluto" <arrguedi at techunix.technion.ac.il>
> Date: April 18, 2004 9:06:50 AM PDT
>
> Thank you very much for your answer.
>
> My intention was not simulating light extinction through the
> atmosphere but
> once light reaches a mist object which is on the ground, (I exactly
> know the
> extinction coefficient within it), analyze the light (direct from sun
> and
> diffuse from sky dome) extinction inside this small volume.
>
> Since I need to know the light levels (illuminance) inside the volume
> at
> different depths, it seems to me that the -av approach will not work.
>
> Any suggestion?
>
> Thanks in advance,
> Guedi