Glare Index calculation

Hello everyone,

I am involved in the simulations of interior Venetian blinds in a
10' wide, 18' long and 10' high
office room with one 6 ' by 6 ' window placed on the south
oriented wall. The window sill height is 3'.
I am calculating Glare index at 4 reference points inside the
room.

There seems to be problem with glare Index. I am attaching the
script for Illuminance calculations and glare Index calculations.
newglares.csh is the file name for the glare script and
finalmultiplesim1.csh is the shell script used for illuminance
calculations.

I just want to make sure that the scripts used are correct .. ?

Thank you

G V DEEPAK
Graduate student and Research Assistant
M.E. Rinker, Sr. School of Building Construction.
University Of Florida.

newglares.csh (265 Bytes)

finalmultiplesim1.csh (527 Bytes)

Hello again.

From a quick look at the scripts I would change the following:

finalmultiplesim1.csh:

You have very low quality settings for the rtrace command
(basically left at the defaults). I would at least increase '-ad'
and add '-as' unless you know it's not going to change the
results.

newglares.csh:

You calculate a picture for findglare with default view settings
(-vtv and -vv 60 -vh 60). The findglare man page recommends
to use a fisheye (-vta) and 180 degrees for the view angles. With
your images findglare has a lot to compute from the octree.

The rpict options are left at the defaults (including ab=0!). I don't
think that's your intention.

findglare itself could do with more options as well. Best thing
to do is to set the rpict/rtrace options in a variable and use
this on the command line for all of the commands (rtrace, rpict
and findglare).

You also should look at the way how findglare works. The
default threshold to identify glare is 7 times above the average.
Given that you're looking at a bright window (very large
source) you may never find a glare source unless you're
looking directly into the sun. If that's all you need, fine, otherwise
you have to work out a reasonable threshold for your scene.

Regards,
Thomas

Thanks a lot Mr Bleicher, I would try these options out and see if they work out.

Thanks again.

ยทยทยท

On Fri Dec 05 08:26:38 EST 2008, Thomas Bleicher <[email protected]> wrote:

Hello again.

From a quick look at the scripts I would change the following:

finalmultiplesim1.csh:

You have very low quality settings for the rtrace command
(basically left at the defaults). I would at least increase '-ad'
and add '-as' unless you know it's not going to change the
results.

newglares.csh:

You calculate a picture for findglare with default view settings
(-vtv and -vv 60 -vh 60). The findglare man page recommends
to use a fisheye (-vta) and 180 degrees for the view angles. With
your images findglare has a lot to compute from the octree.

The rpict options are left at the defaults (including ab=0!). I don't
think that's your intention.

findglare itself could do with more options as well. Best thing
to do is to set the rpict/rtrace options in a variable and use
this on the command line for all of the commands (rtrace, rpict
and findglare).

You also should look at the way how findglare works. The
default threshold to identify glare is 7 times above the average.
Given that you're looking at a bright window (very large
source) you may never find a glare source unless you're
looking directly into the sun. If that's all you need, fine, otherwise
you have to work out a reasonable threshold for your scene.

Regards,
Thomas

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G V DEEPAK
Graduate student and Research Assistant
M.E. Rinker, Sr. School of Building Construction.
University Of Florida.