[George Lentz]

I am new to Maxwell and am trying to learn to use the IES lights for my interior renderings. I have been successful in assigning IES Emitters to materials using the Maxwell provided IES files, but cannot get Maxwell to recognize commercially available files from sources such as; CREE, Halo, Philips, etc. My IES Viewer program can read them, but will not render. Any suggestions?

[CDRDA]

I'm not sure what the issue could be, I do not have any problem either when creating an IES based material in Sketchup, or the Maxwell material editor. Are you sure the files you are trying to open are .ies, or .ldt files? These are the only two file types Maxwell supports.

If the issue is that the lights are not rendering, perhaps you need to up the light intensity. There is also the problem in Maxwell that IES lights do not produce light from their source. So while they will light the scene, you need at least one other light, such as a simple emitter (for example a flat plane) placed at the source of the light with a low intensity. There has been discussion about this elsewhere on the forum and I think Mihai mentioned something about using 3 lights for each fitting.

[Mihai]

You don't need to do that, you just need to apply it an IES emitter to a small sphere in order for the light pattern built-in to the IES to look most accurate. I'm not sure if several plugins already create that little sphere behind the scenes and others don't. I'd suggest to read the docs on your plugin to see how to set up IES lights.

Could you please post one of these files which don't work?

[George Lentz 20180319011419]

I seem to be limited to only uploading images. I cannot upload a file, but here is the link, http://www.lightingproducts.philips.com/our-brands/lightolier-usa/corepro-led-downlight.html#!f=%2b%40Category%3aDownlighting%2b%40SubCategory%3aGeneral+Purpose+Downlighting

[Forum Moderator]

Hi George,

Checking one of the files, I noticed in the first line after TILT=NONE they put "1 -1 1 181....."

The second value should be the number of lumens of the lamp instead of -1 (as per the standard). You can edit the file make the change yourself.
However, we find that this is a common practice of the different brands lately. Making a search, I have found what that value means: "The initial rated lumens for the lamp used in the test or -1 if absolute photometry is used and the intensity values do not depend on different lamp ratings."

I guess in the case we come to support that -1, we should show light intensity units instead of a simple multiplier as we have now.
I'll speak with the developers to see if we can make a change to support that.

Cheers!
Fernando

[Forum Moderator]

Hi,
We have already made the changes in the code in order to support absolute photometry in IES files (that -1 value). So, in the next version, you won't have to change that value.

Cheers!
Fernando

[George Lentz 20180426020345]

Thank you for reaching out to the developers. I downloaded the updated version, but I am unable to reproduce the results. I have IES files from many commercial lamp manufactures and all with the same result. I am confident that these files are written to an industry standard because all the IES viewers I use can view them. Two that I use are 'DIALux evo' and 'IES Viewer' . At this point the only solution I see is to see if I can find a similarly profiled Maxwell IES file and then reduce the intensity to match the desired lumen output or perhaps you could explain in more detail how to edit the commercial IES files to make them readable to Maxwell. I appreciate your input.

[Forum Moderator]

Hi George,

Yes, the change has been made in the code, but we have not released a new version yet, so the public version does not include it. However, the next update will include it.

Making the change is quite easy. Please check the following image:

Absolute Photometry IES.png

You can edit the IES in Notepad or any other text editor. You have to locate the second figure after the informative part and type a non-negative value like 1 or 100, for example. Then save it and that's all.

It should work like that.

Cheers!
F.

[George Lentz 20190421010421]

So, I have the new 2019 Sketchup plugin. Should I expect that the handling of IES Files have been fixed?

I appreciate your reply,

George