Honeybee hourly solar radiation

Hi Mostapha! Won’t be the first nor the last to say that the plug-in is incredible!! Thank you and keep up the good work!

I have a question regarding the solar radiation analysis. I would like to analyse the solar irradiation on a surface within urban context, but as far as I understand the Ladybug_Radiation_analysis tool does not take reflections into account. I also need the hourly irradiation. Is there a way to achieve this with Honeybee?

Hi Mihail,

  1. You can use Honeybee to model radiation with Radiance. There you can define the materials for every surface and it will calculate the reflections.

  2. If you are looking to get hourly values for all hours of the year then you need to run an annual analysis. Use DSParameters component to change the study to radiation rather than illuminance. The rest is very similar to annual daylight analysis.

If you haven’t done any daylight simulation with Honeybee before there are couple of example files here: (https://app.box.com/s/znns0dtewd1tclicx74q) and here is a full workshop (https://www.youtube.com/playlist?list=PLkjfDmSc5OryXkWSt57ltJFU4qXD…).


Hi Mostapha!

Thanks for the reply and the links!

I am trying to do this now, but I run into some problems:

  1. If I use the Daysim component where should I generate the sky from? Since there is no sky my analysis doesn’t run. Earlier, I have tried the hourly solar analysis using the Grid-based, where I can generate a sky, but then I have to run 8760 simulations, which takes quite a long time.

  2. If I want to examine 1 surface (PV panel) and I want to have surroundings, which are not taken into the analysis, but still generate shading and reflections, there is no input to the analysis component?


Hi Mihail,

  1. your skies are generated automaticaly from epw weather file
    2) your test mesh will be on the PV panel, and all the surroundings and also the PV panel with RAD materials should be connected as HBObjects,

    from that picture for me your set up look OK, if you followed Mostaphas Video and downloaded the example file that should work.
    One thing what I do is put just one toggle to Write rad and Run rad, (but I chceck my geometry before that) , so it will write the rad file and run it immediately after, but for beggining is good to first just write the rad file, chceck the geometry and than run it



Hi Peter,

Thanks for replying!

'So for the sky then I guess it uses a climate based sky for every hour, if I am not wrong. How does this perform compared to the GenCumulativeSky? I want to achieve as accurate irradiation as f.x you can get from DIVA (but there you cannot get the hourly irradiation).

Can you please look at the files, because I have done everything, I think, but when running the simulation it says that there is no light source, ending up with no results?

Untitled.3dm (203 KB)
Hourly solar.gh (105 KB)

Hi Mihail,
The error : no light source- is for the interior lights (so it s not for you (now))
and it ending up actuaaly with the result of .ill files, you just need to read them as the daylighting results but instead of LUX you have KWh/M2 or WH/m2,
I added to your definition some “readers” where you can go through the whole year every hour, or period of time etc. you just need to read the results from the .ill file :slight_smile:
and DIVA- so this is actually the same , it uses the same Radiance programs for calcs, and I found HB_LB more powerful than DIVA and easier to visualize the results



Hourlysolar.gh (446 KB)

Hey Peter,

Thanks for the help! Everything is working perfectly :slight_smile: HB_LB indeed is a very powerful tool

All the best


Thanks Peter for your help. Just a minor correction here that Honeybee and DIVA are both using Daysim for annual analysis. Daysim uses a modified version of Radiance under the hood so you are technically correct! :slight_smile:

Thanks for the clarification Mostapha!

I am interested, what is the difference in the modified version of Radiance?

Hi Mihail, To start you can check this paper for the details about how Daysim works:

Bourgeois D, Reinhart CF, Ward G, “A Standard Daylight Coefficient Model for Dynamic Daylighting Simulations” Building Research & Information 36:1 pp. 68 – 82, 2008.

There are more here: http://daysim.ning.com/page/publications

Thanks! I will check them out.

Hi @PeterZatko,

Could you please upload again the file. I am facing the same problems addressed in this topic. One doubt, does Daysim takes into account direct solar and diffuse radiation?


I need to estimate hourly solar irradiance on building envelopes (one value - average solar irradiance of all the walls and the roof) for each building in the urban neighborhood. I understand that annual solar irradiance could be captured in terms of sun hours, not on a building level but at the pixel level using Rhino-Grasshopper. However, I am not sure how the hourly value can be estimated for a complete year for all the buildings in an urban neighborhood.
Also, I am not able to download the file which PeterZatko shared.
Any support would be highly appreciated.

Hi @Omprakash,

The majority of this thread is from 2015 from the old forum and will refer to the now legacy components.

Here’s a thread that might help answer your question.

Thanks for this @charlie.brooker. However, what I see is the visualization of a surface. On the other hand, I am looking for the same results in multiple building envelopes, i.e. I should get unique solar irradiation on each building envelope for multiple buildings in an urban context. Do you have any suggestions on this?

Hi @Omprakash,

I’m not exactly sure what you’re trying to achieve - have you got any images of what results you have so far and what the missing link is for what you want to achieve?

Apologize for the delayed reply. I started on this when I posted this question and will need some time to work out the flow.