Ladybug: do sun vectors correspond to standard time?

I am quite green regarding ladybug tools and have just discovered this forum through food4Rhino.
I am reposting a question I posed in the McNeel Grasshopper forum.
(I cannot yet upload the file here, so if anyone wants to download it, he/she can do it from there)

I saw this warning in the solar / standard time input: (red highlight)

Up until I saw this, I took it for granted that if you select ‘false’ the sun vectors correspond to the sun’s position according to standard time. (simply put: if you input 12:00, it will return the sun’s vector when your clock says 12:00 at the specific location/date)
I am assuming that if the sun’s position does not correspond to standard time, neither do the sun vectors.
so, do I have to adjust for the time equation manually?

p.s. I am creating a sundial so I’m not interested in the curves or the sun’s positions, just the sun vectors.

A similar question was asked a while ago.
In any case the boolean there makes a difference and changes the vectors: True is the solar time and False is the standard or civil time. I believe also that the hint is wrong and needs to be changed between both options. @mostapha: Am i right/wrong?
In any case the images below show the differences:
TRUE (Standard):

FALSE (Solar):


1 Like

Hi Abraham,
Thanks for the response!

So, just to clarify: are we to conclude that the sun’s position (and more importantly the sun’s vector) are calculated according to standard time (with the boolean = false) and that just the warning text is outdated?

@mostapha you seem to be an authority on the subject, but even in the previous post you didn’t intervene although called upon! :smile:

Maybe I’m being pedantic but I want to be sure before I start printing my prototype!

EDIT: Ok, just to be sure I ‘cast a shadow’ from a point and it drew an anallema on the xy plane. So everything seems to be working fine!

@chris has implemented local vs solar time in Sunpath for Ladybug legacy and he is the right person to reply to this question.

Yes, it seems the description is wrong. I will fit it shortly.

1 Like