How to set up this kind of model

Hi all,

I am wondering how should I set up this kind of model for daylight analysis. I guess it should be multiple zones joined at the end. I tried to union it in rhino, but the resulting brep could not be used as a zone. Also, I have a vertical wall for light bouncing, I am not sure how to include it into analysis.

Also I would like to ask if it is possible to get analysed grid as a curved surface, rather than flat plane.



Hi Petar,

You don’t need to create a zone for this case (however you can). Just use createHBSrfs component and assign the materials to the surfaces (or leave the material input empty if you want to use generic materials). The same goes to the vertical wall.

Back to the second question, you can generate the test points from any surface or mesh. All you need as the input is a list of points and vectors that indicates points direction.

Nevertheless, this looks like a great case that I can use to record a tutorial on how you can prepare a model with Honeybee for daylight simulation. If you provide more information here (such as the model itself and material properties) I can capture the video tomorrow evening and post it on YouTube.


Dear Mostapha,

thank you for your kind reply.

I will be more than happy to provide a model for your demonstration. However, the whole structure is much bigger (around 200x80m) with multiple openings, maybe I could reduce it to half for this purpose. Also, the bottom plane (subject of analysis) is a curved surface, so this could be useful as well. Regarding the material properties, I think a couple of simple material could be used. It would be highly appreciated if you could demonstrate the influence of ’ amount of reflection’ of base surface on overall result (for example, the amount of reflection of walls).

PM me for the model details.



Hi Pitar, Sounds good. I think I will just generate something similar to your test model for this case. I will make sure to talk about materials too. I will update this discussion when I posted the video. Cheers, -Mostapha

Thank you for your effort Mostapha

Hi Mostapha, could you roughly let us know when can be expect the new video?

Hi Petar, I will do it in few hours. Will let you know

Hi Petar, Check the attached file. It is so late right now to capture a video. I will try to do it tomorrow. The file should be good enough to get you started. -Mostapha (124 KB)

Dear Mostapha,

Thank you for the example file, I hope it will be useful. Anyway, no need to rush, I was just asking roughly time, feel free to do it when it suits you the most. You have already provided so much to the community.



Mostapha, let me ask you few practical questions:

For daylight analysis, it is important to use the skylight and not direct sunlight?

Is is possible to visualize the sky which is used for analysis?

How many light bounces are used (or should be used) for daylight analysis? (Since I have seen you can change rad analysis parameters)

I hope this questions are not too banal.



Also, what the is the value of relfctance value of opaque material. is it multiplied by 100 and translated into percentage?

Very very good questions Petar. Good to see that Honeybee has users like you.

  1. It is up to you as a designer to make the decision about using skylight vs direct sunlight or mix of them. It is about the space that you are designing and your design intent. Just think about an atrium vs a museum. And now think of the atrium in two different climate zones. As a [lighting] designer you make the decision on how do you want the space to be, how the climate is and then try to take advantage of skylight and/or direct sunlight to achieve your design goals.

  2. Yes. There is a watchTheSky component next to sky types which let you visualize the sky. There is also an example file that you can check.

  1. This one again depends on your model. For your model I would suggest a minimum number of 4 for your final analysis. -ab is only one of the parameters. Check this slides by John Mardaljevic if you want to have a better understanding of radiance parameters and their effect on the results.

I also added the link to “Tutorial on the Use of Daysim Simulations for Sustainable Design” by Christoph Reinhart to teaching materials. I encourage you to at least read chapters 1 and 2 of the tutorial. Check pages 25 and 27 have two examples about selecting the parameters.

Great questions. Keep them coming.


It is a value between 0 and 1 that indicates the percentage of the light which will be diffusely reflected from the surface. I think I suggested two resources if you hover your mouse on the component or check the help.

Dear Mostapha, thank you for your kind explanation.

I am a little bit confused now, and I would like to ask some more things:

Which sky is used by default for daylight analysis, and how can I influence this? I understand I can create multiple conditions of the sky (with or without the sun), but where I introduce it into, for example, annual daylight simulation? Also, as I understand, I can create sky for specific day and time of day, while annual simulation is running for the whole year, and after it’s done I can extract specific condition for specific time and day as well. Should I create a series of 365 skies, each with 24 variation for this kind of simulation?

Hi Petar,

You can introduce the sky for gridBased and imageBased analysis using the _skyFile input:

For other analysis types the skies are special and that’s why they have their own recipe.

Daylight Factor and Vertical Sky Component are using cloudy (overcast) sky as default. You can use uniform sky as an alternative if you want by setting the input to True.

For the annual analysis, Daysim takes care of generating the sky. You don’t need to generate the sky for each hour as this is exactly what Daysim does.

If you want to watch the sky for every hour of the year you can use Ladybug genCumulativeSky, selectSkyMtx and skyDome similar to what I showed in this video (minute 1:15): ( There is an example file for ladybug that called real time radiation analysis that may also help.

Hope it helps,

Let me know if you have any other questions.


wow… that was great conversation
I learn it a lot,
just about ab value most of the time i use 5…
Dear Mostapha, thank you