algorithmic modeling for Rhino

Hello Mostapha,

As I continue my attempt do the 3 types of analysis required by the UK's Rights of Light 

using LB and HB, (and replace Ecotect), I have some more questions.

So far it seems that the VSC is already there, I now try to understand the APSH as described in the "BRE_Site Playout Planning for Daylight & Sunlight (2011)".

My understanding is that I need to use sunlightHoursAnalysis within the period of 21 Sept - 21 March?

But maybe I am completely wrong...

Thanks in advance for the advice.


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Hi Dimitrios,

I'm not an expert in BRE standards so I don't know what is the analysis period based on the code; but back to your question to calculate sunlight hours for 21 Sept -21 March the attached file was correct. I just did three minor modifications:

1. If you are using analysisPeriod input then hour, day and month component will be disabled. As you can see in the attached file I removed day, month and hour inputs and it just works fine.

2. Make sure you are using the same timeStep for sunlightHours and sunpath components. I just connected the same slider to both inputs. You can go as accurate as a minute but it may take a while to calculate!

3. Set parallel to True so the component will use all the CPUs for the calculation. It makes a big difference if you run the analysis for so many test points.




Thanks a lot!

Very helpful.

When I manage to relate the LB and HB to the specifics of the Rights of Lights I will send you and you can review.

Maybe have them online as examples for this specific task, as it s something all the UK based projects need to use, when proposing new schemes.


To have the example online is such a great idea. Looking forward to it.



Hi Dimitrios,
did you manage to get to the bottom of this?


Hi Mostapha,

I'm trying to relate the UK guidelines on sunlight hours to the Ladybug sunlight hours analysis.

In particular I would compare the result of "Ladybug_Sunlight Hours Analysis" with an APSH (Annual Probable Sunlight Hours) benchmark that is set in the "BRE_Site Playout Planning for Daylight & Sunlight (2011)":

APSH is defined as "the long-term average of the total number of hours during a year in which direct sunlight reaches the unobstructed ground (when clouds are taken in consideration)" and for London is 1484 (while the total daylight hours are 4383)

Now, my question is: Does the output - sunlightHoursResult - of "Ladybug_Sunlight Hours Analysis" take in consideration clouds or the analysis considers the sky always sunny?

If not, can I get a result that takes in consideration clouds or there's a method to "convert" the result in order to compare it with the APSH value set by the guidelines?

@Dimitrios Papadopoulos : Did you manage to sort this issue?



Hi J[D]

The Ladybug "Sunlight Hours" component only takes into account the sun vectors generated from the "Sunpath" component, not the cloud cover or weather data.






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