[Radiance-general] RE: GenCumulativeSky - follow-up questions

[Reinhart, Christoph]

Dear Kam,

 

I think that Darren is in a better position to answer some of your
questions. This is what I can contribute.

 

Q1. I tried to generate cumulative skies for direct radiation (binned)
for different periods of time in a year.  They all give the same
results.  Is it not possible to specify the time and day period for
direct radiation?

 

I added the time periods and reading of EPW files to the program to make
it more user-friendly and compatible with DIVA.I do not think that the
binned option necessarily works with epw files (at least I have not
tested it as we have not brought that option into DIVA).

 

Q2. I created angular fisheye views of the sky dome (180-deg spread with
the centre at the zenith) and found some anomaly that I can't explain:

 

Direct - 

 

a. All sun paths are found within approx. 45 degrees from the zenith.
It looks like a normal sunpath diagram being "cropped", leaving a
circular area in the middle.  I changed the view direct (-vd) and it's
still the case (i.e. not a view setting problem)

 

I cannot explain that. Darren perhaps?

 

b. The sun paths are almost continuous rather than in form 5-degree
"bins"

 

Diffuse -

 

a. The lowest row of the 145-patch sky dome is particularly bright on
the left and right sides (i.e. west and east sides, respectively) .  It
appears under both Singaporean and San Francisco skies.  Would it be
related to the limitation on <6 degrees sun angle?  

 

We have preliminary tested GenCumultativeSky against DAYSIM and
radiation measurements from Freiburg. The paper will be submitted in two
weeks. Diego Ibarra is the main author. We can send a link of the
manuscript to this list once it is available.

 

Yes, a manual would be nice. In case you are interested in looking
deeper, I can provide the code for GenCumulativeSKy (with Darren's
consent).

 

Christoph

 

From: radiance-general-bounces at radiance-online.org
[mailto:radiance-general-bounces at radiance-online.org] On Behalf Of Kam
Shing Leung
Sent: Tuesday, November 30, 2010 8:30 AM
To: radiance-general at radiance-online.org
Subject: [Radiance-general] RE: GenCumulativeSky - follow-up questions

 

Dear Alstan and all, 

 

Thanks a lot for your quick response. It works after I add ".\" in front
of the file name. 

 

May I ask a couple of follow-up questions?

 

Q1. I tried to generate cumulative skies for direct radiation (binned)
for different periods of time in a year.  They all give the same
results.  Is it not possible to specify the time and day period for
direct radiation?

 

Q2. I created angular fisheye views of the sky dome (180-deg spread with
the centre at the zenith) and found some anomaly that I can't explain:

 

Direct - 

 

a. All sun paths are found within approx. 45 degrees from the zenith.
It looks like a normal sunpath diagram being "cropped", leaving a
circular area in the middle.  I changed the view direct (-vd) and it's
still the case (i.e. not a view setting problem)

 

b. The sun paths are almost continuous rather than in form 5-degree
"bins"

 

Diffuse -

 

a. The lowest row of the 145-patch sky dome is particularly bright on
the left and right sides (i.e. west and east sides, respectively) .  It
appears under both Singaporean and San Francisco skies.  Would it be
related to the limitation on <6 degrees sun angle?  

 

Thanks in advance for bearing with this long list of question.  It would
be great if there is a "manual" that can be made available - it's a
useful tool!

 

Cheers, 
Kam 

 

 

 

 

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