ReE: [Radiance-general] I can't get even similar irradiancevalues from a lamp.

[yijun huang]

Also, I'm curious how you'd use LAMPCOLOR for a UV-lamp? Obviously the efficacy would not be the usual 179?

 

YC Huang

 

 
> ------------------------------
> 
> Message: 3
> Date: Sun, 15 Mar 2009 09:54:28 -0700
> From: Greg Ward <gregoryjward at gmail.com>
> Subject: Re: [Radiance-general] I can't get even similar irradiance
> values from a lamp.
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Message-ID: <A45DA6FC-7D4E-4B42-82EF-7FDD5CBECC3B at lmi.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
> 
> How did you measure the UV reflectance of the surfaces of your box? 
> Most paints drop off dramatically from the visible spectrum to UV. 
> White paints may re-emit UV as visible so they appear "whiter" under 
> daylight illumination. You really need to know the behavior of your 
> paint with respect to ultraviolet wavelengths to do this correctly.
> 
> -Greg
> 
> > From: Minki Sung <minki.sung at gmail.com>
> > Date: March 14, 2009 10:52:03 PM PDT
> >
> > Dear Radiance users,
> >
> > I'm writing here for third time and I always sorry for just asking. 
> > I'm modeling a small box has a several bared cylindrical 
> > fluorescent lamps (actually UV lamps) inside and want to know the 
> > irradiance level on the surfaces of the box. The cylindrical lamps 
> > has 32mm in diameter and 540mm in length and The radiance of 44W/sr/ 
> > m2 calculated with the UV output of the lamps (7.5W) was applied to 
> > the lamps. Before calculating the small box model I checked 
> > irradiance values with an experiment measuring UV intensity at the 
> > distance of 1 m and compared that with the same simple RADIANCE 
> > calculation and the result was reasonable. However, the calculation 
> > results are higher than those of experiments by 2~4 times with the 
> > small box model. The small box is not simple but not so 
> > complicated. I have modeled the lamp both as a cylinder and 72 
> > polygons but there were not so much changes. Only one channel was 
> > used to calculate irradiances of UV from modeling to issuing 
> > results and only diffused reflections were assumed. Geometric 
> > errors or abnormal radiance distributions of lamps could be assumed 
> > to cause the discrepancy, but 2~5 times are too large
> > Here is my rtrace options.
> >
> > cat pts_sensor.pts | rtrace -I -oov -ar 128 -ad 512 -as 256 -ab 2 - 
> > ds 0.02 uv.oct > uv.dat
> >
> > It would be appreciated if anyone give me advice.
> >
> >
> > Sung
> 
> 
> 
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> 
> End of Radiance-general Digest, Vol 61, Issue 11
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