Honeybee-core vs lbt-honeybee

Both libraries contain honeybee module, but they do different things.

May I know the reason because they do not look intuitive

At this point in time, lbt-honeybee is the library for the current version of Honeybee[+] that only does Radiance simulation (no energy). This library is the version that everyone who has currently installed HB[+] from Food4Rhino is using.

In Spring of 2020, this lbt-honeybee version will be phased out in favor of separating honeybee libraries by extensions. So there is a core honeybee library that contains the common objects for all of honeybee (aka. honeybee-core) and then there are extension libraries for each engine honeybee will connect to like honeybee-energy for OpenStudio/EnergyPlus simulation and honeybee-radiance for radiance simulation. These libraries are all WIP at this point but the honeybee-core library isn’t likely to change much before the Spring release (at this point, it’s mostly the extension libraries we are working on).

Hello @chris,

Thank you very much for your comments! I think right now the Room objects (and other geometrical objects) in honeybee-core and lbt-honeybee are not mutually compatible. For now, I am wondering if the only solution is to create two separate geometrical objects for radiance simulation and energy simulation?



Dear @chris,

Also, if I use the Radiance software, SolarCal will not be used since they are probably not compatible since these two different algorithms do different things? Is this is true, do you have any recommendations on calculating E_solar on the human body which is required for determining ERF?




Yes, until we complete honeybee-energy and honeybee-radiance in a couple of months, you’re really only going to be able to make Radiance models with lbt-honeybee.

You can use this function in the SolarCal module to get shortwave MRT delta on a person from the horizontal solar components that Radiance give you:

This discussion shows how you can do it with [+] Grasshopper components:

Edit: Sorry I should have read the post you referenced a bit more in detail… So the module I should use would be SolarAccess.

I will take a crack at it. Thanks!

Dear @chris (and also @mostapha ),

Sorry to bother you again. In regards to your comment:

I am not sure how to obtain the direct and diffuse horizontal solar components from Radiance simulation though. I thought the only output Radiance (specifically ray tracing) will be able to give would be 0: Illuminance(lux), 1: Radiation (kWh), 2: Luminance (Candela) according to this .py module.

To make it more clear of my question: I am running an indoor simulation, which means that there are opaque surfaces that can block the sunlight, which is also why I need to use tools like Rhino/Radiance to determine the points in space with the sun blocked. If I am running the outdoor simulation without other shading surfaces, then I can just simply use EPW file to get diffuse and direct horizontal radiation and avoid using Radiance altogether.

Thanks and I again I am so sorry to have to bother you with so many questions.


Is it an annual study or a point-in-time study? That can make a difference on how you implement the workflow but in both cases you can generate radiance skies for direct and indirect irradiance. See the manual for gendaymtx for annual studies and gendaylit for point-in-time.

Dear @mostapha,

Thank you for your advice. I think it makes sense now. Additionally, I am wondering why each run of Radiaince simulation give me different answer for diffuse radiation?
I will post a separate discussion on the Radiance fourm but since you have extensive experience with Radiance so may be you know the answer?



This has been asked several times. See here: Difference in the daylighting illuminance between two simulation with the same conditions?

Dear @mostapha,
Thank you for your response. However, I think the original link to the forum posting is now broken. http://comments.gmane.org/gmane.comp.graphics.radiance.general/2685

Do you still remember what has been discussed over there though?


Search for radiance stochastic sampling and you should find a number of similar discussions on the Radiance mailing list as well as here.

Hey @mostapha,

  • Sorry to bother you again. In this original post you mentioned

set radPar to be high

There are multiple parameters that you can set for raytracing. So did you mean to set the quality to high quality (i.e. quality = 2)? But high quality will make the rendering time much longer right?

  • A final thought: is it possible to have deterministic solution for diffuse radiation?