[Radiance-general] How to verify an IES file ?

[Thomas Bleicher]

Vaib

I also used to do a quick parallel simulation in something like Dialux
that's specialized in artificial lighting simulations. If you feed it with
the same input values for maintenance factor and room reflectance you
should get a similar output as with Radiance. You need to be familiar with
these tools though because they have some hidden or implicit options that
you need to account for. But then, so does ies2rad, I think.

Thomas


On Thu, May 22, 2014 at 12:31 PM, Vaib <vaibhavjain.co at gmail.com> wrote:

> Hi Thomas, Christopher,
>
> I used a similar luminaire of different make (Zumtobel Claris, Thanks!
> Christopher), and it gave quite similar results to the initial luminaire.
> That means that initial IES file was fine (even with Candela Multiplier of
> 8.6). I then reduced the luminaire's brightness to 50% (as Thomas
> suggested) by using "-m 0.5" in ies2rad. Now the simulated illuminance are
> quite close to the measured ones.
>
> Though I will calculate Lamp Loss Factor using the standard method to
> fine tune the results further. Thank you !
>
> Best regards,
> Vaib
>
>
>
>
> On 22 May 2014 19:09, Vaib <vaibhavjain.co at gmail.com> wrote:
>
>> Thanks Thomas, Christopher
>>
>> I have used "ies2rad -dm -t white -m 0.85 TX4948.ies". I will now check
>> with similar luminaire of another make, and also calculate a representative
>> Lamp Loss Factor as Thomas suggested.
>>
>> Best,
>>  Vaib
>>
>>
>> On 22 May 2014 18:44, Christopher Rush <Christopher.Rush at arup.com> wrote:
>>
>>>  What command line syntax and options do you use with the ies2rad
>>> command to create your radiance definition of the light fixture? It could
>>> be an error with the particular manufacturer’s IES file, if they’ve somehow
>>> made the IES file incorrect in the process of normalizing the IES file and
>>> applying the 8.6 multiplier. In other cases IES files are sometimes
>>> reported with a candela multiplier of 1.0 (instead of normalizing them
>>> first). Can you test with another manufacturer’s IES file of similar
>>> distribution, efficiency, and lamp type (maybe Zumtobel Claris).
>>>
>>>
>>>
>>>
>>>
>>> *From:* Vaib [mailto:vaibhavjain.co at gmail.com]
>>> *Sent:* Thursday, May 22, 2014 6:04 AM
>>> *To:* Radiance general discussion
>>> *Subject:* [Radiance-general] How to verify an IES file ?
>>>
>>>
>>>
>>> Hello Everyone,
>>>
>>>
>>>
>>> In the following report, the simulated illuminance (artificial lighting)
>>> is un-reasonably high than the measured illuminance. I suspect that the
>>> issue may be in the lumen output (or candela multiplier) in the IES file.
>>> Please have a look at the report.
>>>
>>>
>>>
>>> Artificial lighting report: http://bit.ly/1qXigtU
>>>
>>>
>>>
>>> May I request your suggestions on how this issue can be resolved ? How
>>> much shall I reduce the Candela multiplier, if that is to be done ?
>>>
>>>
>>>
>>> Best regards,
>>>
>>> Vaib
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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>>
>
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