Here is the analysis with Honeybee/Radiance. There is a difference between the sky that is generated by Honeybee and the one that is generated by Ladybug. Ladybug uses radiance’s gendaymtx utility which is more recent than gencumulativesky which is used by Honeybee.
thanks for analyzing this problem.
I have checked the file you uploaded and indeed the results from ladybug (gendaymtx) are way more reliable that the ones I got from honeybee (gencomulativesky) as also it can been seen from the pic (left honeybee, right ladybug). Is the same problem I got from my study.
now what is interesting me very much is knowing which sky is using the annual daylight simulation component: is it using genskymtx or gencomulativesky?
Also do you think this problem is due to the sky generation or maybe is the EPW?
Ladybug cumulative radiation uses gendaymtx.
Honeybee cumulative radiation uses gencumulativesky.
Honeybee annual daylight is using Daysim which is using gencumulative sky.
Honeybee[+] annual daylight is using Radiance and gendaymtx.
Based on this topic the issue can be because of the weather data. Gencumulativesky had a known issue for low sun angle calculation which was fixed while ago but if possible I suggest using gendaymtx. We’re removing all the dependencies to gencumulativesky in the [+] libraries.
I have run some test to see whenever I can spot the source of the error. I run the radiation in ladybug, honeybee, and to check the gencomualtivesky I also run it in DIVA. I test it for both the original tokyo file I provided, and also the one you modified to match the integer numbers as per default, as per this post
The results are shown in the picture below
The deviation in the radiation analysis with gencomulativesky of honeybee legacy it appears to be quite visible.
Based on what I read and what I understood, gencomulative sky and gendaymtx are using the perez sky to generate the sky vault. This means that they both use DNI, DHI plus latitude and longitude.
So, what it differs, and maybe it is here that I am confused, is that while in gencomulativesky the sun position is approximated, in gendaymtx the sun position is exact.
Also something that I could not find is which sky model gencomulativesky and gendaymtx in honeybee-ladybug are usign: Tregenza or Reinhart or else.
It could be possible that in this specific case with these file, there is something that is no working properly.
Because honeybee [+] is still under development and since I am looking for an daylight-energy study, i think that my best option for now would be stick with the legacy version, but I would like to be sure that the results from the daylight analysis are exact.
I will wait for your insight.
Thanks for helping me here and for the development of such amazing tool.
Daylight analysis is using gencumsky through Daysim and Honeybee’s cumulative sky calculation doesn’t affect the results for daylighting. Give me some time and I will get back to this issue. It’s a quick check between the skies. You can also use watch_the_sky component in Honeybee which renders an image to what @sarith shared in his post.
thanks a lot to have a look at it although you are busy.
In this case what it seems to be the problem is not the different luminances generated by the two software, but the completely two different directions to where the radiation from the sky volt is hitting the sphere, as you can see in one of the pictures I uploaded before in this post. I know that because of Monte Carlo there is always a difference between simulations, but the differences you can see here are quite large.
For what I can understand I am using the same definitions, that is why I rise this issue.
Thanks again for having a look at this, and I would like to have your insight whenever you will have time.
I appreciate greatly you are taking time to solve this issue. I will wait of course until you will have time to have a look at it .
I tried to use this component but I had two different errors and could not plot the skyes. One (in the first picture) is that it could not find the irr file.
I changed the directory to an easier one and I got the other (second picture) where it says that the parameter is not valid.
I also check this post but would like to know if you have an easier way to solve it now.
Also I can post this issue in the post directly.
@devang, I am laughing so much for my ingenuity!
Thanks for the tip.
I used the Climate Based sky for a precise hour, as you showed, and also I try the entire year with gencomulative sky (you can see the pictures) @sarith, the renderings you posted here in this tread are from native radiance or you used honeybee?, because for what I can tell you used gendaymtx maybe?