Question about Shades in LBT Honeybee

Thank you so much, you guys are the best! I didn’t have the opportunity to test the 1.0, yet but I went through almost all examples from GitHub and the new release looks AMAZING!

In the examples i couldn’t find an answer to one question - for energy analysis - should the context buildings be modelled as HB_Shades from now on (as I do not see dedicated Context components or inputs anymore)? I assumed so from the purple color (these super visualisation components btw!!!) in Revit picture from release notes :slight_smile:

I also spotted a small mistake on GitHub page - I belive this section should be renamed to: honeybee-grasshopper-energy


Hi @Wujo ,

You are correct that Shades now have their own object type that is completely separate from building envelope Faces (Walls, Roofs, Floors).

You’ll see that there’s also a completely new Model object type that holds all of the geometry objects for simulation. Shades can be included in energy Models by either assigning them directly to the Model (representing context shade) or you can assign them to other Honeybee objects (Rooms, Faces, Apertures, Doors) in order to represent building-attached shades, balconies, furniture, etc.

More info about the structure of Honeybee Models can be found in the documentation here on the Wiki:

Thanks for finding the typo. Will fix it now.


Thanks for this precision Chris! What about the modelling of the ground surface (often modelled as a simple plane) surrounding the building, to take into account the soil albedo for a DF/DA calculation? Shall we model it as a Shade object or is it already implicitly considered in the Radiance incoming solar irradiation (which would explain it is not modelled in the new example file “annual_daylight”)?
Thanks for your support and your huge development!

Hi @Romain ,

Your question is more of a general question about how Radiance accounts for the ground than it is about anything specific to the new LBT Plugin vs. the Legacy Plugin.

By default, all Radiance daylight simulations include an emissive ground hemisphere that is just like the emissive sky hemisphere. So this allows you to account for the ground in the case that no ground surface has been input. The emissive ground surface coincides with an assumption that the ground has a reflectance of 0.2, but, because the surface is emissive, you won’t be accounting for things like context shading the ground and therefore reflecting less light from certain areas. This is why it is often more accurate to include a ground surface in Radiance simulations but, if you leave it out, your results usually won’t be that far off.

In Legacy, the way to input the ground surface was to create a HBsrf but you usually had to override the Radiance material to ensure the surface had the right reflectance of the ground. In the new LBT Honeybee, you should model it as a Shade and, as long as this shade isn’t assigned to a parent Room, Face, Aperture or Door, it will have the 0.2 reflectance by default.

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Thanks for this helpful clarification Chris!