Lighting Calculations with .ies files not working

[mthomas45]

Using several different manufacturer's .ies files for LED lighting gives me 0.00 fc in spaces with lights in them.  As I understand previous versions of Revit are not able to handle absolute photometry in LED .ies files.  It produces insanely low Coefficient of Utilization numbers.

Has this been addressed in any update?  This is extremely frustrating.  I'm in 2018.3.

[Judy_S]

Hi, mthomas45,

I'm Judy from Revit support and I'll be glad to try to help you out with this question. The problem of the large negative coefficient of utilization that you've been getting has been fixed in Revit 2019. You could try making a copy of your model that you can upgrade (without doing so to the production model) so you can do the calculations in the newer version.

Let me know if this helps!

Thanks,

Judy_S

[Judy_S]

Hi, mthomas45,

Just wanted to check with you to see if you have any questions about my post. Let me know if there's anything else I can do to help!

Regards,

Judy_S

[Anonymous]

Hi @Judy_S

Just checked the issue in Revit 2019, and it seems the issue still exists, absolute photometry files are not recognized

Regards,

Ahmed Attia

Senior Electrical Engineer - BIM Specialist , LEED GA , P.E.

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[HVAC-Novice]

for LED ies files you need to "convert" them to regular ies file:

- rename file from an ".ies" to a ".txt" file

- replace the "-1" with  the lumen output number (absolute lumens)

- save file and rename back to an ".ies" and use in Revit

Alternatively I recommend using elumtools plugin for lighting design. it can handle with LED ies-files directly and has many other useful features.

[mthomas45]

I tested this in 2019 and it seems to have been resolved.  But if others are still experiencing it, I may need to dig deeper.   Staff here isn't really keen on editing the manufacturer's .ies files if it can be avoided.

[Anonymous]

For those experiencing problems with .IES files in Revit, try changing from ANSI to UTF-8. Works for me.