identifying glare source dimension

hdri
1

Hi,
What is the idea behind evalglare or findglare identifying the daylight
glare source dimension eg: in case of windows. Can somebody give
information regarding this.

Nithya

2

Hi Nithya,

From the findglare man page:

Findglare normally identifies glare sources as directions that are brighter than 7 times the average luminance level. It
       is possible to override this determination by giving an explicit luminance threshold with the -t option. It usually works
       best to use the 'l' command within ximage(1) to decide what this value should be. Alternatively, one can use the 't' com-
       mand within rvu(1). The idea is to pick a threshold that is well above the average level but smaller than the source
       areas.

There are a lot of caveats when using findglare, so be sure to read the whole thing:
http://radsite.lbl.gov/radiance/man_html/findglare.1.html

Evalglare was the product of Jan Wienold's dissertation, which can be considered the prime source for info on how evalglare does its thing. Here's a good paper on actually using evalglare:

http://www.ibpsa.org/proceedings/BS2009/BS09_0944_951.pdf

···

From: nithya merin [mailto:[email protected]]
Sent: Monday, November 25, 2013 8:50 PM
To: [email protected]
Subject: [HDRI] identifying glare source dimension

Hi,
What is the idea behind evalglare or findglare identifying the daylight glare source dimension eg: in case of windows. Can somebody give information regarding this.

Nithya