[Radiance-general] lighting fixtures data

[william reynolds]

Greg
Good timing 'eh!
I was hoping to find IES data, but I have heard of EULUMDAT -> IES 
converter somewhere, so that would be possible too. failing that, i 
figured anything was better than nothing, and i'd work out how use the 
data once i got it if it was a different format!

the HDR idea sounds really interesting though. unfortunately i know 
nothing about it as yet, but i'll try google as my next step!
Any help you could give me would be really appreciated - this input 
method sounds very helpful as i do have access to the lights, a dark 
room and a camera!

I dont quite understand how you would get the data into radiance though 
- the only idea I can think of at he moment would be to somehow convert 
the pixel brightness information into a .dat file that you then used 
with a source as normal. So I guess you would need to turn the photo 
into .pic file, and then somehow extract the pixel brightness data into 
another file and interpret it, perhaps converting it to ies format? or 
even stright to .dat?

am i wildly out, or somehow along the right lines. i'm thinking on my 
feet, and there my well allready be something with in radiance to do all 
this!

thanks for the suggestion. off to look up HDR now!
will



Gregory J. Ward wrote:
> Hi Will,
> 
> Funny you should mention this, because here I find myself attending  Rob 
> Shakespeare's "Virtual Scenography in Live Performance" symposium  at 
> Indiana University <http://www.indiana.edu/~vslp/>, where a bunch  of 
> theater types and researchers are gathered talking about lighting,  
> simulation, and the like.
> 
> I will definitely ask Rob if he has any data, and maybe he'll respond  
> with some pointers as well.  Are you planning to input this directly  
> into Radiance, or do you have other tools in mind as well?  (I.e., do  
> you need IES format data, or can you get by with something not easily  
> converted to IES?)
> 
> The reason I ask is that I've been toying with HDR imaging as a quick  
> and convenient method to get at certain types of photometry, where  the 
> projection angle is small but the pattern potentially complex --  i.e., 
> theater lighting instruments.  The method is simple, but there  are a 
> few details to work out.  Basically, you set your instrument  and point 
> it at a blank wall or ceiling or some diffuse, white  surface large 
> enough to encompass the beam.  Then, you take an HDR  photograph of the 
> beam pattern.  The part I haven't worked out  completely is using this 
> as input to Radiance, but if you have some  basic distance and beam size 
> measurements, this should be  straightforward.
> 
> You would of course need a reasonable digital camera -- SLRs are  
> generally better due to the better flare characteristics of their  
> lenses, and access to the light instrument of interest and a dark  room 
> to do the measurements.  If this is of interest, I would be  happy to 
> help you assemble an example photometric distribution as a  proof of 
> concept.
> 
> -Greg
> 
>> From: william reynolds <william.reynolds at oriel.ox.ac.uk>
>> Date: March 3, 2006 6:55:37 AM EST
>>
>> Hi there
>>
>> I've been trawling the internet for a while now looking for ies  data 
>> files (or any other standard fot that matter) for theatrical  lighting 
>> instruments, with out any luck at all.
>>
>> I've found lots of data architecturial lanterns, and lots for the  
>> actual bulbs (from ge, osram etc)but these aren't very useful when  
>> you're trying to light a theatre, with the lanterns that are  
>> available there.
>>
>> The only best photometric data i've found is from ETC:
>>
>> http://www.etcconnect.com/docs_downloads/datashts/S4_19_Deg_vD.pdf
>>
>> where they give you a "Candlepower Distribution Curve" as well as  
>> field and beam angles, but most places dont even give that.
>>
>> I also have the problem that most of the lanterns i'm interested in  
>> are focusable, and many are zoomable as well, so i need data at a  
>> couple of focus/zoom settings (i can then interpolate between these).
>>
>> Does anyone have any ies (or other useful format, or even radiance  
>> format) files about any theatrical lanterns? ideally i'm after  
>> selecon lanterns, but i would be happy with some generic data for  the 
>> standard lantern types:
>> -profiles (of various angles)
>> -fresnels
>> -pc's (less important)
>> prerferably data at a couple of focus settings, and data for 1kW  and 
>> 500W lanterns.
>>
>> I dont have access to the facilities to make my own measurements,  and 
>> i can't figure out how to use the data provided (http:// 
>> www.seleconlight.com/english/support/english/acclaim%20fresnel.pdf  
>> for the selcon fresnel i'm particulary interested in) to estimate  the 
>> figures.
>>
>> So if anyone can come up with any advice, or has any suggestions of  
>> where I can get hold of this data it would be very much appreciated.
>> [I will be using the data in part of an undergraduate engineerig  
>> degree project, and wont use anythign for any commercial purposes  if 
>> it makes any difference to anyone].
>>
>> Thanks for your help everyone
>> will
> 
> 
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