[Radiance-general] IES files and MGF geometry

[Guglielmetti, Robert]

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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