Hello again,
i wanted to ask if there is a detailed documentation about the Annual Irradiance Recipe? So what is the workflow, which Radiance commands are used?
And in general, does the Recipe use rtrace for calculating the irradiance values?
Any help appreciated 
rtrace is applicable when you add up the time-step radiation for each sky-patch (of a discretized Reinhart sky model) into a single sky file and then trace rays to it. This was Robinson and Stone’s approach which I believe was followed in Ladybug and Honeybee (legacy) a few years ago. The current approach is based Daylight Coefficients and involves calculating time step values of irradiance using gendaymtx and then rfluxmtx or rcontrib.
You can find the relevant command in the Annual Irradiance Recipe here , which in turn relies on the honeybee-radiance library to setup the simulation command through Radiance.
In my opinion, unless you are planning to integrate a new recipe to the list of existing LBT recipes and then distribute that to everyone along with Ladybug Installations, scripting a recipe is probably an overkill.
Regards,
Sarith
Hijacking this thread @sarith , this Annual Irradiance Recipe, is it able to just run for specific hoys of the year (hence reducing simulation time when other hoys are not of interest)? I tried via the .wea and “schedule” input, but it seems that the simulation is running through all hoys of the year, am I missing somthing? Thanks!
Thank you for the detailed explanation, then i will have a look into the Recipe and rcontrib to get a deeper understanding.
I agree, that scripting a new Recipe would be an overkill. But just out of curiosity or if neccessary at one point, how would i be able to script a recipe? Because i wanted to have a look at that, but as i asked in this Thread (Editing or creating lbt-recipes) i didn’t get how i can do that.
Thanks again for your help.
Sunny Greetings,
Yannick
I also wanted to run the Recipe for specific hours of the year and it is possible. I posted the solution in this thread: Using time periods shorter than a year in Annual Irradiance Recipe
The WEA-File created with the code shown in the solution can be then used in the Recipe as WEA-Input.
Maybe that answers your question
Limited linecode knowledge here, how exactly does one use this code inside grasshopper, is it possible to have a component with the necessary inputs outputs?
@mikkel would be the right person to tell you the exact steps (if you are working with Radiance). But typically, you’d have to start with making a new contribution to the exisiting recipes while following the existing code-style and syntax etc. In this specific case, you would be adding a new recipe to honeybee-radiance while utilizing the underlying libraries. The recipe would then have to be incorporated into the GUI via the grasshopper plugins.
Things are bit more sophisticated now with the new LBT plugins, but I got my start by asking question similar to yours around ten years ago.
Hi mikkel,
I am not sure if this solution works, i have a feeling that the simulation still goes through all hours of the year despite an hoy input on the “wea from epw”. Can you also check if my assumption is right? Thanks
Hi @IasonBournas,
It should only return results for the selected hoys. However, since the ray tracing is coefficient based a fewer number of hours will not affect the ray tracing – except the direct sun calculation which would use fewer sun positions.
Here is an example where I use LB Analysis Period to create the hoys only for March.
