[Radiance-general] IES files and MGF geometry

[Axel Jacobs]

Hi Rob,

thanks for your reply.  Yes, MGF is still alive and kicking--now
officially endorsed by the IESNA as far as I understand.

The product I'm looking at is this:
http://products.iguzzini.com/iway_round
which is why I want to get rid of the top and bottom bits of the
ies2rad geometry.

What I was hoping to be able to do with MGF is tell it what the
fitting looks like.  In this particular case, I'd model 3 stacked
cylinders, enclosed with a disk at the top. Only the middle cylinder
would act as an emitter.  Does that make sense?

Best
Axel



On 5 November 2014 14:33, Guglielmetti, Robert
<Robert.Guglielmetti at nrel.gov> wrote:
> Hi Axel,
>
> Oh wow, an MGF question. In all my years, never. Wow.
>
> Interesting question. I'm not sure what having the MGF description will
> buy you in terms of your problem. The MGF is just a geometry section
> AFAIK; the photometry is still tied to the ies-format data, so I don't
> think you gain any added flexibility there. Depending on how diffuse the
> top and bottom of the luminaire are, you probably *could* remove the rings
> and have a reasonably fair distribution for the cylinder, but I'm guessing
> they are some really diffuse, blobby lenses and so you're getting some
> scatter. Another option would be to generate the simple geometry with
> ies2rad and then add some sort of "caps" with added geometry to the top
> and bottom of the luminous geometry created from ies2rad. Not sure how
> accurate the "thing" needs to look, versus the space lighted by the thing.
> If you only care about the distribution, this option may work for you.
>
> - Rob
>
> On 11/5/14, 5:14 AM, "Axel Jacobs" <jacobs.axel at gmail.com> wrote:
>
>>Dear list,
>>
>>would anybody happen to have an example of an IES file with MGF
>>geometry that they are happy to share?  I have the latest LM-62
>>(2002), but it doesn't even mention MGF, and I don't seem to be able
>>to find an example ies file with embedded MGF.
>>
>>The reason why I'm looking into this is this:  I have a round bollard
>>light and need to generate the distribution for only the vertical
>>cylinder, but not the top and bottom which ies2rad generates as well.
>>I figure that removing the top and bottom 'rings' would invalidate the
>>photometry.
>>
>>Many thanks
>>
>>Regards
>>
>>Axel
>>
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