[Radiance-general] Re: Radiance-general Digest, Vol 38, Issue 14

[steve michel]

A linear fixture is exactly what I had in mind. For a while I even searched 
for 'bare bulb' photometry files from big lamp manufacturers (GE or Philips) 
but none exist for fluor tubes (only par and mr16 spots). But is the illum 
distribution method another one or a subset of using flatcorr and lboxcorr 
techniques you describe??

>From: Rob Guglielmetti <rpg at rumblestrip.org>
>Reply-To: rpg at rumblestrip.org,Radiance general discussion 
><radiance-general at radiance-online.org>
>To: Radiance general discussion <radiance-general at radiance-online.org>
>Subject: Re: [Radiance-general] Re: Radiance-general Digest, Vol 38, Issue 
>14
>Date: Thu, 26 Apr 2007 09:31:02 -0600
>
>Mark de la Fuente wrote:
>>Steve,
>>  Rob is pointing you in the right direction.  But be careful when you 
>>wrap the fixture in an illum box as the light output may be quite right.  
>>It's been a while since I've had to do this, but I recall having issues 
>>with "flatcorr" and "lboxcorr" in my brightdata definitions (created by 
>>IES2RAD).  I'm not sure where these are documented, but I'm sure other 
>>functions are used for spheres and rings.  I believe the sphere option is 
>>the easiest to work out, but only works if you can wrap your fixture in 
>>the illum sphere and the sphere does not bisect geometry.  In my case I've 
>>had to work out linear fluorescent pendants which have required a box.
>Yeah, like I said, it's far from straightforward.  =8-)  Mark is right, the 
>sphere is easiest, but since the illum enclosure must completely contain 
>the luminaire geometry, it's not the best choice for a long skinny thing 
>like a fluorescent strip.  The sphere ends up so big you introduce 
>inaccuracies.  So those cal files lboxcorr and flatcorr take the ies2rad 
>.dat output -- which is essentially a point distribution -- and wraps it 
>around more apporpriate geometry: a box in the case of lboxcorr, (for a 
>linear pendant fixture) and a flat rectangular polygon in the case of 
>flatcorr (for say a recessed fixture where the luminous aperture is a 
>single plane).
>
>- Rob Guglielmetti
>
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