Simulating IES lamps file through RAD materials

Hi to everyone,

in this tutorial ( ) is shown a method to simulate a lamp in DIVA. Considering that the process is about a modding of radiance materials, do you think that it would be possible to do the same in honeybee?

To go deeper I have tried to do the tutorial about DIVA, but in its grasshopper version: it doesn’t work. To be more precise, the material, applied to a brep, is not read by the **DIVA **daylight simulator. Actually I don’t know if I’m mistaken about some details.

it would be great if only it could be possible in honeybee! for instance I have found this study which is pretty interesting to calculate lamps power consumptions directly in honeybee:…

Thank you,


Hi Claudio,

Thank you for sharing the links. Similar approach can be applied to Honeybee however it is not currently implemented. I personally don’t want to implement lighting simulation to Honeybee at this point. So much can go wrong there for inexperienced users.

I saw your discussion on DIVA page and I’m pretty sure Alstan will have a solution for that. Keep me posted about the results. If you really need it for your studies I can apply it to Honeybee over the next weekend.

Tuan’s work is also pretty interesting. Thanks for sharing. I wish I could read more details about his project.



First try:

Hi Claudio,

Check the attached file for the WIP component. I ran couple of test cases and the result looks fine but the results still should to be validated.

Also it will only work for IES files with rectangle surfaces. Do you have any elliptical examples? You can also read IES2RAD manual page: (

Let me know how it goes.

Mostapha (115 KB)

Wow, amazing work. I’m quite luck not having surfaces different from rectangles, however, it would be nice to be able to include rounded shape diffusors within the foreseeable future.

I will try to check if results are fine trying a comparison between 'Bee and Dialux (using IES file for both to be sure that results derive from tha same input).

Glancing at the Zumtobel website (or Philips, or whatelse) there should be some stuff to feed the new Honeybee component IES2HB.

Thank you,


Hi Mostapha,

doing the test I see that some IES files are not converted by the new component. I mean that ies2hb creates a batch file in the folder without make it running. If I execute it, however, it creates the file (*.rad & *.dat) and everything goes ok. Actually I have no idea about where the problem is: the command in Python looks fine but I’m not good at programming [line 175: runCmdAndGetTheResults( "/c " + batchFilePath) ].

In addition to this I guess that creating an input (domain 0 -> 1) able to modify the multiplier parameter in the IES file before the conversion to the radiance format would make it complete.

I have attached the IES file to let you try how it runs.

let me know your thought,


PS: the IES attached is taken from . It is also quite curious how the component creates two polygons where is applied the light material.

I have found some interesting data sheets about IES file format:…

42915795_(STD).IES (1.9 KB)

Here it is. Actually I finished the work, got the results and… It has stopped working right now. There should be a problem somewhere in copying luminaries (or at least, I made a mistake). What do you think about it?

Values seem to be fine:
- max difference 8% (E avarage)

  • min difference 1% (uniformity)

I hope this is a great news,

eval.rar (1.96 MB)

Thank you Claudio. This is amazing! I will test the files this weekend.

Meanwhile what is the version of Windows that you are using and do you have administrative privilege on your system. I wonder if there is a permission issue that stops RAD2IES to run.


Sure. Sounds like a good ides. I will add -m option to the component, and I will check the links. Thanks again.

Win7 pro and I log in as the administrator. Anyway I’m going to check all my profile settings. Despite this you will be able to verify that 'HB_run_daylight simulation" component might give you back the ‘IES luminaire 42915795_(STD) is scaled or rotated and cannot be added to the scene’ error.

Thank you,


Everything works fine here on my system. I internalize the results for you in the attached file. (452 KB)

Hi Mostapha,

I’m due to start the analysis I said last week, however, the IES2HB doesn’t make its bat file running. Remembering what you told me, I’m logged in as administrator but nothing still happens. Any ideas?



Hi Claudio, Does it run if you double click on the batch file?

Yes, it does. Either I’m logged as Admin or not. If I do a static analysis it is ok, but if I use the multipliers as genes it doesn’t work not doing all the process automatically.

Ha! So it only happens during the optimization studies?

Have you tried to add a delay in the process? You can either do it in Grasshopper or inside Python. That may help.

I can’t test it right now but I can give it a try later today or tomorrow. I may also add a check and if the results are not produced re-execute the batch file.

No, I mean it happens always, but in static analysis I can run it manually and the analysis works.
Sorry , I have been not clear enough

Hi Claudio,

I added an extra check to the component. It will re-run the batch file in case it fails the first time. let me know if it solves the problem.

Mostapha (8.57 KB)

Hi Mostapha,

it seems working very well. Thank you again for your time you spent for me and for your whole project as well. It has been very helpful for my studies.


Hi Mostapha,

Thank you very much for your reply - the IES to HB component is grey and seems to be working however it gives me no output. Do you know what I did wrong please?(rad and bat files attached) Also I had to double click on the bat file to get the rad one - the component did not generate the rad.

Many thanks

Test1_0.7_ies2rad.bat (194 Bytes)

Hello, this is with example file called IES2HB_WIP_III too and the radiance file attached (in this case I had to edit the BAT with the following line to generate the RAD manually “ies2rad -o Test4_NoModif_1.0 -m 1.0 CDM-i_25W_10deg.ies”) This is the April version of HBtoIES:

testarthur.rad (599 Bytes)
testarthur_ies2rad.bat (195 Bytes)
testarthur.dat (749 Bytes)