Radiation Results - LB & HB


I’ve been preparing this discussion for some time now.

I was in doubt if continue this discussion or start a new one. So here we are: a new one.

There are 2 issues that are bothering me with the radiation results, specially when comparing the results from LB with those of HB.

Issue 1: Results so different.

In the attached file upper part to the right of the canvas you see both definitions (LB and HB). The images obtained show results so different that i can’t find a logic explanation (2.46 vs 41 kWh/m2 for the same period of time). I believe that LB are in the OK range. HB are to high for just 5 hrs of calculation. I don’t believe the material definition are making such a big difference (though i tried to have them similar).

Issue 2: Can’t get annual grid based calculations plotted.

In the attached, right side at the bottom. I get the calculation, but after connecting the results to the HB_readAllTheDSHourlyResults it takes ages to calculate and at the end rhino crashes. Can be that this is a memory problem? Or there is a way to make this work (total annual radiation for GridBased simulation)? For now i disabled the component, but i just wonder …

Words of wisdom for both issues will be appreciated.



05_SunlightHourAnalysis_CrossTower-V0_Honeybee_Done_01.gh (630 KB)

Hi Abraham interesting topic. I used to get different results from HB vs LB.but I always thought it was me doing something wrong. I can’t look at your definition right now, I’m on my phone. I’ll be watching this post closely
Thank you cheers

I hope i’m doing something wrong. The alternative is much less desirable …

Another thing i’ve noticed. In the file i attached, when i send only one hour in HB (say from 10 to 11) the radiation image is black, like nothing is in there. It required at least 2 hours.


Hi Abraham,

I’ve only dipped my toes in LB/HB and as you know I tried doing a radiation analysis of an office building using the Ladybug 02_Radiation.gh template which you advised was wrong to determine indoor radiation.


So a beginners question…Can physical model elements (modeled in Rhino or GH generated geometry like spandrels, sunshades, window apertures, glass planes) be used instead of the HB_GlazingBasedOnRatio component?..used as a sort of 'context" element to block insolation? If so is there a tutorial I can jump to that would better explain that process?

Hi Robert,

There is plenty of material to start from, if i understood your question/request.

I suggest all those wonderful video tutorials that Mostapha prepared for Daylight analysis using HB: https://www.youtube.com/playlist?list=PLkjfDmSc5OryXkWSt57ltJFU4qXD…

There are also excellent videos that Chris prepared for E+ simulations, but they can also be used for Daylighting purposes. See: https://www.youtube.com/playlist?list=PLruLh1AdY-SgW4uDtNSMLeiUmA8Y…

Basically the answer to your question is YES. You can use rhino models/GH generated geometry and use them for the simulation purposes. But i don’t want you to get this answer as absolute. There are many considerations that according to them you want to use HB definitions, that in many cases make your life more comfortable. There are other cases where you do want to define your own model and input it on HB. So each case has its own constraints.

Hope it helps a bit.


Hi Abraham. I will check your file as soon as I can. Back to part 1 I assume that you’re already using a climate-based sky? Otherwise it’s expected.

Hi Robert,

If you can provide a simple example of your geometries I can put a Hydra together on how to prepare your geometry surface by surface.



I’ve only modelled a building mass and context. Was going to model skins in either Rhino/GH or Revit but didn’t do so becuase I was unsure about what kind of geometry LB/HB would accept.

Honeybee can handle mesh or breps. The workflow with brep is more straight forward. If you can share part of your file I can put a workflow together as I have been thinking to do it for a very long time.

Hmmmm …

I’m using HB_genCumSky.

The reason is that i want to get the whole year radiation (or any other desired analysis period). The hint for this sky says to use it ONLY for radiation analysis, since it is using the Gencumulativesky.

The HB_genClimateBasedSky asks for specific month/day/hour.

I’m getting the feeling that, in effect, i’m doing something wrong …



Give me a few minutes to dumb down the mass and apply a simple skin. I’ll give you the 3DM and the GH I was working with.

M, Here we go. I stripped out a bunch of context to lean up the model.

I sent you my LB solution so you can see how I wired for floors.

There is an ON/OFF switch at the left to turn on the solution.

There is an underlying mass model from which i use GH to slice floors. I solve for one floor and use the remainder as context.

I added a rudimentary skin composed of spandrel (solid), sunshades (solid), and glazing. I just made these quickly and haven’t adopted the geometry into the GH solution.

Thanks pal!

Sunshading Analysis For Mostapha.3dm (4 MB)
FRA_Paris.Orly.071490_IWEC.epw (1.48 MB)
Sunshading Attempt with Mostaphas template - Radiation.gh (391 KB)

You’re probably doing it right. I guess the difference is coming from gencumulative sky vs gendaymtx. I know that gendaylit (climate-based sky) and gendaymtx match for hourly tests that I have done.

Here you go! (http://hydrashare.github.io/hydra/viewer?owner=mostaphaRoudsari&amp…;)

The file may take couple of minutes to run. You may want to lock solver before opening the file.

If you have any specific question about this file I suggest to start a new discussion with a more related title.

Wow! Lightning quick…did you mean to post a 3DM and GH?

You can download it from the Hydra link. I internalized everything in the Grasshopper file.

Hmmm is it me or this discussion started by Abraham got hijacked.

Robert please dont take this badly but I think you should start your own discussion topic aside from this one. Maybe is too late now but I think is fair enough to say that.

Back to Abraham discussion. It is interesting to know that there is a difference in the gendaymtx vs gendaylit returns different results. I’m still not able to see the definition but I will when I get back home…traveling right now so I’m n my phone


Hi Claudio. Don’t worry. I’m checking the file right now and will have a definite answer soon. That was my hypothesis. Let me check and I will update the discussion.


I’m not trying to “hijack” anything. Yesterday I posted an issue about radiation calcs and Abraham invited me to a thread he was opening because he thought my issue was germaine. If i jumped on the wrong thread sorry but serious? “hijack”?

Yeah you are right Robert. No Hijack then, My sincere public apologies