What type of sky is generate for daylight simulation in HB+ and new HB1.3? (Isotropic, Anisotropic)

grasshopper honeybee[+]
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#1

Hello everyone,
I have a question regarding the type of sky used in the simulations of Honeybee [+] and the new LBT.

What type of sky (i.e. isotropic or anisotropic) is used in the recipes such as RAD, ANN, DC, 3 and 5 phases in Honybee [+]? The input is a skymatrix generated by the SkyMatrix component through a WEA file but I don’t get which type of sky is created exactly. Is it an anisotropic one based on the Perez sky model or something else??

And what about the new LBT? which sky is used for these same analyses (except 3 and 5 phases ones that are not yet implemented)?

Hope that someone can clarify that to me

Matteo

#2

Perez Sky with Reinhart discretization (almost sure). @mostapha can confirm.

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#3

Thank you @sarith for your answer!
I guess the same sky is also used for Honeybee_Radiance in the new LBT since it can be seen as the direct evolution of the [+] version.

#4

I can confirm that both the HB Annual Daylight and the HB Annual Irradiance recipes in the latest LBT plugin will model the indirect illuminance/irradiance using Tregenza subdivision with 145 patches.

Note that, for both of those two recipes, the direct contribution is modeled using the “enhanced 2-phase” method that @sarith developed for his PhD thesis, in which rays are traced directly from the sensors to the disc of the sun. So, even though the indirect contributions of these recipes are modeled with a fairly coarse sky, the direct contribution should be much more accurate than it would be with a patched sky dome.

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