Hi,
I remember that I once have seen a paper on modeling the color gradients of the sky dome related to weather, time and location information, and if I am not completely wrong, the authors had done that work using Radiance. I am aware of several models for creating color gradients, but I could not find anything that has been applied to Radiance. Of course I am aware of Mark Stock's skycolor.cal, but that one takes known colors as an input. Does anyone else have information on the topic, how to set extend radiance brightness distribution by color models for the sky dome?
Thanks!!! Lars.
Found it, it is linked here:
http://www.cs.utah.edu/vissim/papers/sunsky/
"A Practical Analytic Model for Daylight" by A. J. Preetham, Peter Shirley, Brian Smits
I am interested in this, too. How best to make it work? Convert the formulae in the paper to a .cal file (that modifies a mist volume or a dome-like source?) Pre-render a sky dome? Modify the Radiance source itself?
Since it is unlikely that one of us has the extra classes to make the authors' sample code work, I volunteer to share what I come up with if I get done first.
Mark
···
On Thu, 16 Apr 2009, Lars O. Grobe wrote:
Found it, it is linked here:
http://www.cs.utah.edu/vissim/papers/sunsky/
"A Practical Analytic Model for Daylight" by A. J. Preetham, Peter Shirley, Brian Smits
I am very interested in a colored sky model as well Mark. Thank-you for
offering to share! This work would be a perfect topic to present at the
Radiance workshop in November. FYI, 3ds Max Design already has the Utah
sky model implemented. It generates really impressive sunsets.
Christoph
···
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Mark
Stock
Sent: Thursday, April 16, 2009 9:26 AM
To: Radiance general discussion
Subject: Re: [Radiance-general] sky models and color gradients
I am interested in this, too. How best to make it work? Convert
the formulae in the paper to a .cal file (that modifies a mist
volume or a dome-like source?) Pre-render a sky dome? Modify the
Radiance source itself?
Since it is unlikely that one of us has the extra classes to make
the authors' sample code work, I volunteer to share what I come
up with if I get done first.
Mark
On Thu, 16 Apr 2009, Lars O. Grobe wrote:
Found it, it is linked here:
http://www.cs.utah.edu/vissim/papers/sunsky/
"A Practical Analytic Model for Daylight" by A. J. Preetham, Peter
Shirley,
Brian Smits
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general
Hi!
I am interested in this, too. How best to make it work? Convert the
formulae in the paper to a .cal file (that modifies a mist volume or a
dome-like source?) Pre-render a sky dome? Modify the Radiance source
itself?
I think that there are two ways. One is to generate a mapping on a
source object, the other is "modeling the athmosphere". The second
option is quite ambitious, and may depend e..g. on photon map, spectral
rendering and other stuff (i.e. modifying mist parameters only exists in
Radzilla, not in Radiance Classic now afaik). The first option seams to
be more realistic with Radiance Classic - so the formulae would have to
be translated into a colorfunc, and the near-distance atmospheric
effects could be modeled using mist.
CU Lars.
I converted that model to a radiance dome, i usually work with radiance with aesthetical purposes so i'm not sure it's phisically accurate, it misses the atmosferic effects because, as Lars said, i think it's necesary to modify radiance code. I did it as part of a 3dsmax exporter to rad i'm working with.
I got the main sources some time ago from a web page of the University of Girona in Spain (sir project), i think they created the sources based on some code related to the paper, i've returned to search for the project again but i haven't found it on the internet.
It's a windows .exe file, the program creates three data files with radiance colordata and outputs a radfile with the definitions of the sun and the sky and a white box to avoid radiance no objects error, it uses a calc file ssky.cal to map the data to the dome, the parameters are
lat Latitude (0-360)
long Longitude (-90,90) south to north
sm Standard Meridian
jd Julian Day (1-365)
tod Time Of Day (0.0,23.99) 14.25 = 2:15PM
turb Turbidity (1.0,30+) 2-6 are most useful for clear days.
gesky3 lat long sm jd tod turb (gesky 43 3 3 180 10 6 >ssky.rad)
you can download: www.aisarquitectura.com/archivos/ssky.zip
When i got it there were some code missing and i could not compile it as it was so i modified it, but not to distribute because i don't know the protocols to add new code (comments, licenses ...), so i can send the source code to anyone who is interested in cleanning it or somebody could try to help me in make it better
Ignacio Munarriz
Reinhart, Christoph escribió:
···
I am very interested in a colored sky model as well Mark. Thank-you for
offering to share! This work would be a perfect topic to present at the
Radiance workshop in November. FYI, 3ds Max Design already has the Utah
sky model implemented. It generates really impressive sunsets.
Christoph
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Mark
Stock
Sent: Thursday, April 16, 2009 9:26 AM
To: Radiance general discussion
Subject: Re: [Radiance-general] sky models and color gradients
I am interested in this, too. How best to make it work? Convert the formulae in the paper to a .cal file (that modifies a mist volume or a dome-like source?) Pre-render a sky dome? Modify the Radiance source itself?
Since it is unlikely that one of us has the extra classes to make the authors' sample code work, I volunteer to share what I come up with if I get done first.
Mark
On Thu, 16 Apr 2009, Lars O. Grobe wrote:
Found it, it is linked here:
http://www.cs.utah.edu/vissim/papers/sunsky/
"A Practical Analytic Model for Daylight" by A. J. Preetham, Peter
Shirley,
Brian Smits
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general