analysis for 50% daylight coverage at any given time

Hello there,

I am trying to figure out a way that I can discover the number of total minutes that a test surface receives at least 50% (at any given moment) of direct sunlight exposure between 9am-3pm.

Is there an easy way to do this in ladybug? Please see my grasshopper script and .3dm file below.

Attachments:

170202_sunlight analysis.3dm, 3.8 MB
170203_sunlight analysis_script_parametric building heights_percentages.gh, 453 KB

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Replies to This Discussion

Permalink Reply by ClaudiavV on February 2, 2017 at 11:34pm

this is a tricky one

Permalink Reply by Devang Chauhan on February 3, 2017 at 2:51am

The way I see it, this component is about whether you receive sunlight or not at a particular time. It won't count a 50% sunlight.

It could tell you if a certain point receives sunlight for at least 50% of the time. But I am not sure if that's what you're looking for.

Permalink Reply by ClaudiavV on February 3, 2017 at 4:17pm

Hey - to elaborate further than below, I am not concerned if one point receives sunlight for 50% of the time. I need to find out for how long is the entire surface receiving at least 50% sunlight coverage. So if at 10am only 40% of the surface is getting sunlight then that time wont count, but if at 11am the surface is getting 50% sunlight coverage then that will count towards how long in total it receives 50% or more.

Permalink Reply by Devang Chauhan on February 3, 2017 at 2:36am

Hi Claudia,

Could you please elaborate on your question? I want to look into this, but I am not sure if I understand you correctly.

-Devang

Permalink Reply by Aurelien Keller on February 3, 2017 at 6:29am

hi Devang,

The way I see it, she is looking for the number of hours for which the teste surface is at least 50% exposed to the sun, but not sure about it.

Aurelien

Permalink Reply by Devang Chauhan on February 3, 2017 at 7:40am

If that's the case then that can be done with this component I believe.

Permalink Reply by ClaudiavV on February 3, 2017 at 4:13pm

Hi Devang,

yes, Aurelien is correct. I want to know the number of hours for which the test surface is at least 50% exposed to the sun. So for how long is there >%50 sun exposure on the surface - does that make sense??

Permalink Reply by Mostapha Sadeghipour Roudsari on February 3, 2017 at 4:20pm

Use sunIsVisible output, flip the matrix, count the number of True values and divide it by the number of total hours, count the number of values that are larger than 0.5.

Permalink Reply by Mostapha Sadeghipour Roudsari on February 3, 2017 at 4:21pm

PS: I assumed each sun position represents an hour otherwise you need to divide the file value by the number of time steps to get the number of hours.

Permalink Reply by ClaudiavV on February 3, 2017 at 4:25pm

Thank you so much Mostapha! I will test this when I can on Monday and post my results - thank you for you help!

Yes - the sun position represents every hour between 9am - 3pm.

Permalink Reply by ClaudiavV on February 3, 2017 at 7:08pm

Mostapha, what do you mean by 'flip the matrix' ?

Permalink Reply by Devang Chauhan on February 4, 2017 at 12:56am

Hi Claudia,

Please find a sample attached. I have added a small component that helps you calculate the number you're interested in. The component has tooltip descriptions.

In the attached file, I am calculating the number of minutes as you mentioned in the original post. However, you can change the _timeStep_ on sunpath and set it to 1 to get the number of hours.