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Can radiance calculate the DGI ?

asked 2014-12-10 21:00:46 -0500

yongqingzhao's avatar

updated 2017-05-04 08:55:31 -0500

I want to get the DGI parameter using radaiance,But I am a new radiance user,and don't kown how to implement it in radiance.Is there anyone that can guide me? Thanks!

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answered 2014-12-11 14:44:10 -0500

updated 2014-12-12 14:16:47 -0500

The simple answer is "yes", Radiance can be used to compute DGI -- at least, it can provide high dynamic range images for inspection to derive DGI. This paper details the derivation of the metric, and discusses its limitations as well.

Your workflow for using Ecotect would be to generate hemispherical fisheye view renderings of your design with Radiance, and apply the mathematical basis on them, or (easier) use evalglare to interrogate the HDR images and give you DGI (evalglare will also give you DGP and a host of other metrics as well).

BTW, Evalglare is most likely going to be part of the standard Radiance distribution in the near future. In the meantime, I think the only link to it is here.

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@rpg777 The reason I am interested in calculatuing DGI is that the DGI is required by Chinese daylight design standard.And I always use Ecotect combined with Radiance to perform daylight analysis.

yongqingzhao's avatar yongqingzhao  ( 2014-12-11 22:36:29 -0500 )edit

answered 2016-02-23 19:35:15 -0500

updated 2016-02-23 19:38:04 -0500

Evalglare (see the PDF at calculates DGI, as well as several other daylight metrics, and it is now part of the NREL Radiance distribution. If you're using it as a design tool as well as to satisfy Chinese code requirements, I recommend looking at DGP.

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Asked: 2014-12-10 21:00:46 -0500

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Last updated: Feb 23 '16