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Changing photometric files of defined luminaire

Is there a way to change the photometric file of a defined luminaire to a new photometric file without having to redefine or add a new luminaire?  It would be nice if I could define the luminaire using a photometric file...let's say an exterior area luminaire with a type III distribution, and swap out just the photometric file with a new type IV distribution without having to load and define an entire new luminaire.  Is that possible?

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I think the answer is a partial 'yes' on this one, Jill, but there are gotchas depending on the situation.

Firstly, I'll run you through how it's possible (although for this method to work you can't have any of the fixtures in question on a Frozen project - AGi32 won't allow you to run a calculation, freeze the results, and then change the luminaire type that you've used in that calc), then expand on some concepts from there.

Steps to take:

  • Open the 'Define Luminaire' dialog box
  • Turning off 'Smart Symbols' if you haven't already done so.
  • Turn off 'Auto Define', if you haven't already done so
  • Select the fixture that you want to replace
  • Copy the 'Label' text (select it and use 'Ctrl+C')
  • Click the 'Select' icon
  • Choose your new photometric file
  • Click the Label text box and paste your old label into it (use 'Ctrl+V')
  • Click 'Add/Redefine'
  • From there, you have to make a few adjustments depending on your requirements

AGi32 will automatically fill the Tag and Description fields with the Defaults set in your 'Defaults...' dialog box. There is nothing you can do to stop this, and it may mean that you have to amend these, depending on what you need. But, assuming you need to make a change there are some helpers:
  • You have to enter any change to the Tag manually (no way around this)
  • In the Description text box, if you need to make a change, and a previous luminaire had the same, or similar description to what you need, start typing a few characters, and then hit the 'Down' cursor key on your keyboard. You can scroll through a list of existing descriptions in that file until you find a match, or a close one (e.g. You might find one that you just need to change from type III to type IV)

Lumens (lamp and luminaire), Number of Lamps, the calculated efficiency, and the Watts are derived from the file, and those need to update from your previous luminaire for good reason. If you have a need to update these, that's understandable in certain circumstances, but I agree with AGi32 not retaining your previous information as it can affect your calcs and you should only change these with clear knowledge of what you're doing and why.

The new photometric will override 'S/P Ratio', 'Total LLF', all the 'Luminous Box' info, 'Arrangement', 'Arm Length' (if applicable to the Arrangement). It may also override Pole and Pendant Mounted information, but I would urge anyone to avoid using these unless they are very experienced with them (calculations can be adversely affected).

Now, of the above things (in that last paragraph) that you've had to possibly update, the only one that I sort of agree with is the Luminous Box stuff - all the other items could be retained from previous info, but the Luminous Box is again derived from data in the photometric file. It doesn't necessarily mean the info in the photometric file is correct (it often is not, in relation to luminous openings), nor even if it is technically correct will it mean that you'll never have to change it (e.g. for a shoebox fixture where the insertion point is offset from the luminous opening). You should check these boxes to make sure that the figures are correct for your luminaire (although from my observation many people gloss over this area of luminare definition).

Lastly, since you turned off the Smart Symbols at some point, your symbols should be the same as before, but beware - if you have selected a CCT for the 'Luminous' colour of the Render Mode symbol, there is a very good chance that AGi32 has turned this into an SRE filter for your updated luminaire, meaning that it will reduce the output of the fixture by the SRE factor (e.g. if in your first luminaire you specified a HPS fixture with the CCT code HP01 so you could see its non-white output in your renders, your new photometric file will replicate that CCT appearance by applying an SRE value of 0.38 (meaning you get 38% light output from the fixture) in the Color Mixer dialog with an RGB value of 255,63,0.

Hope that helps more than it confuses!

Cool. I just posted a fairly detailed answer and it disappeared when I posted it.


I can't re-write it all (sorry), but in a nutshell, when you select your new photometric, use the 'Label' of the fixture you're replacing.

AGi32 will unfortunately overwrite most of your old information, but a couple of minor timesavers are:

  • Turn off 'Smart Symbols'
  • Turn off 'Auto Define'
  • If your new description is similar/same as an old one, type a few letters then use the 'Down' cursor key to scroll through the possibilities existing in the current luminaire descriptions

If you've specified a CCT value in the 'Luminous' section of the Render Mode symbol area, your new fixture will look like it's retained that CCT colour, but if you click the Luminous color you'll find that it's probably replaced that CCT value with an SRE color filter factor (for instance, a HP01 HPS CCT in your first fixture will turn up with an SRE value of 0.38, meaning that you'll get a 62% reduction in light output from this new fixture). This is a bug in AGi32 that's existed for many years and versions, and is currently showing no signs of being addressed by Lighting Analysts. Use CCT at your peril (it can often return bad results in fixtures created through the above method, through Collections, and through importing AGi32 files).

 Is there a real answer to this question???????

What's not real about the answers I gave, Miketrol?

By the way, Flo, nice forum name. Now I'm just waiting to see if Al Eedee turns up here.


I have been searching the forums for a similar answer - dealing with emergency egress lighting. While our state does not require a submittal for code, we typically do them to calculate that we have met the requirements. That said, I would like to alter a few lights that are on emergency battery backup with a lower lumen output. I was looking for a way to modify/copy the existing luminaire and decrease the lumen output, but I cannot. I altered the wattage to see if it would calculate the lumen output accordingly, but it doesn't. Any way around this?

Hi, Lisa.

To be honest, it sounds like there's some conflicting information there. You do a calculation to confirm that you've met 'the requirements', even though you do not require a 'submittal for code'. Here in Australia, the methods by which you confirm compliance are very explicitly defined, although I don't assume that is the same for every location around the world.

If your emergency lighting codes are strictly defined, then you should follow their approved methodology - anything else is pure supposition. For example, I could not comply with our emergency lighting standard via the method you're trying to use; how do you know what your lower lumen output is unless you have a proper test report? If you don't know for certain, then all bets are off. If, however, there's some information that you have where you know for certain what your emergency lighting lumen output is from your fixture, and you can't change the fixture lumens (assuming you're struggling with an 'absolute' file where the lumens are 'locked' in AGi32), then aside from actually modifying the IES file your only other avenue is to use the Total LLF text box, or preferably the click on the 'Specify...' button and put your normal depreciation factors in but them also add the reduction factor for emergency in the 'User Defined Factor' box.

Remember that these factors are decimal values from 0 to 1, so assuming your emergency lighting lumen output is something low like 8% of the original lumens, you'd but 0.08 in the User Defined Factor box.

I should clarify something - when I said I couldn't comply with the local requirements here via your method, I'm saying that because it sounds like you're using a bit of guesswork on the reduced lumens.

In the past here we would get emergency classification codes for our fixtures that we could use with tables to determine spacings of fixtures. In the last decade or two it's more common to also receive IES files for the emergency fixture where we can do lighting calculations with the tested reduced lumen output fixture, so we never have to mess around with the file - it's a known entity.

Thank you! I have the lumen output from the specifications, but not an .ies file for that output, which would make life so much easier. I will try the user defined factor as you explained.

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