Hi guys !
For the purpose of my work i often need to make radiation calculation with a define method where i calculate the radiation with different position of the sun, with a certain angle. I would like to know if it is possible to define the sun poistion by altitude and azimuth angle rather than hour day and month.
Thanks a lot !
It’s not currently possible to enforce the sun position but can you help me to understand the overall workflow? Do you need to generate the sun vector?
PS: Welcome to the forum! 
Your profile picture is missing. Please set it up when you get a chance. Cheers.
Hello Mostapha !
thanks for the warm welcome !!
Yes exactly, i would like to be able , to generate the sun vectors, because the european norms is asking to calculate the solar factor from specific specific angles and not specific hours.
I actually don’t know what is the logic of usin angles that doesnt not always exist in a specific location and what would be the effect on the skyparameters ?..
I’ll add my picture as soon as possible
Hello Again Mostapha, To be a little more specific our goal is to perform a radiation analysis on a surface cover by vertical shaders. the mesurements has to be done from a 0 to 90 degree (step of 5 degrees) angle (Azymuth) and a 0 to 75 degrees (step of 5 degrees) Altitude angle.
This for calculating the impact of the shaders on the facad regarding different orientation.
Since it is not possible to choose the vector of the sun regarding angle we chose the worst case scenario (21 june 1pm) and we modify the orientation of our object instead of changing the sun but we are a bit surprise by the results which are showing quiet a lot of radiation when the facade is parallel to the sun vacetors and the shaders are completely protecting the facade is there any virtual ground in the calculation that could reflect on the facad ?
Hello Mostapha,
What do you think of my request ?
Do you have any idea on how to run my simulation ?
Hi thom.sic,
I think what you should do is to retrieve the sun vectors that correspond to the targeted sun altitudes and azimuths by using the dispatch component, as sun vectors, altitude and azimuth all are sun path’s component outputs… If you are looking for the sun vectors corresponding both to the sun altitude and sun azimuth in the aproriate range, you can then use the AND boolean operator, or perform a dispatch for the altitude first, and then for the azimuth…
Not sure if you are looking for sun vectors or for the appropriate dates to run radiation analysis, but in the second case, you can obtain in the same way the Hour Of the Year, and convert it in a suitable date or analysis period…
I hope it will help, you know where to find me if you need 
Thanks Thomas Soumahoro, !!! You re so amazing i d like to meet you !!
Why don’t you just rotate a Vector3D by azimuth and altitude angles to generate the desired sun vector?
Yes, that’s exactly what i want to do but i didn’t find the tool to generate the sun from a vector.
How do i transform a 3d vector into a sun a vector ?
Sun vectors are just Grasshopper vectors. So just use altitude and azimuth angles to create a sun vector. Here is and example:
sun_vector.gh (9.1 KB)
Thanks Mostapha, i thought that there were metadata in it related to the ecw file.
