[Radiance-general] Specularity Definition of Radiance Material

[Kolomenski, Andrei (JSC-SF311)[WYLE INTEG. SCI. & ENG.]]

Hello Radiance Experts,

I have used a Hemispherical Spectral Reflectance meter to measure the Specular Included (SCI) and Specular Excluded (SCE) SPDs of a material. The obtained SPDs are in the range of 360 to 740 nm., commonly considered the photopic range. Then I compute the total photopic specularity using the equation below.

[cid:image002.png at 01D10B51.83998D30]


For a black shiny metal sample, I compute a specularity of 21%. Is it correct to use a value of 0.21 for my specularity definition of a metal material primitive. I’ve read that specularity values greater than  0.1 are not realistic (http://radsite.lbl.gov/radiance/refer/ray.html#Materials) in Radiance. In the .hdr rendered image, the material appears to be highly specular to the degree that it acts like a mirror. So this why I’m concerned if I’m using the right procedure to define the specularity for the Radiance metal primitive.

Is it correct to use a hemispherical reflectance meter, and the equation above to define the Radiance specularity term.

Thank you for your input,
Andrei Kolomenski





From: Adriana Lira [mailto:adrianalira at post.harvard.edu]
Sent: Tuesday, October 20, 2015 3:50 PM
To: Radiance general discussion
Subject: [Radiance-general] from a rad and a dat file to ies

Hi Everybody,

I was wondering if it is possible to create a *.ies file from a *.dat and a *.rad file. Originally, I used the ies2rad command to obtain a *.rad and a *.dat file from an IES file. Then I did some edits on the *.rad file and now I would like to create an IES file again. Is it possible?

Best,

Dra. Adriana Lira Oliver
Diseños Sustentables Integrales 3E, S.C.
Directora
w  www.3esc.com.mx<http://www.3esc.com.mx/>
e   adriana.lira at gmail.com<mailto:adriana.lira at gmail.com>
t    62 84 84 89
c   04455 21 07 61 41
d   Oxtopulco 31-1, Oxtopulco Universidad,
     Del. Coyoacán, C.P. 04318, D.F., MEXICO

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