HB Glass Modifier Bugged?

Hello folks,so I am working on a university project and wanted to be more specific about the glasses for a radiant study.

Honeybee Radiant v.1.5 does not want to go above .91 _trans.
“1. solution exception:Input number green transmissivity must be between 0 and 1. Got 1.00182493033”

Honeybee Legacy has no problems with this. Did I misunderstand something or even mess up the installation?

I hope you can help me out.

that does look like a bug, its doing the same on my end, I’ll see if I can’t find where the problem is and send a PR

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if anyone’s curious where all I’m looking I’ll keep this updated:

Runtime error (AssertionException): Input number green transmissivity must be between 0 and 1. Got 1.00182493033

  line 87, in float_in_range, "C:\Program Files\ladybug_tools\python\Lib\site-packages\honeybee\typing.py"
  line 107, in g_transmissivity, "C:\Program Files\ladybug_tools\python\Lib\site-packages\honeybee_radiance\modifier\material\glass.py"
  line 63, in lockedsetattr, "C:\Program Files\ladybug_tools\python\Lib\site-packages\honeybee\_lockable.py"
  line 67, in __init__, "C:\Program Files\ladybug_tools\python\Lib\site-packages\honeybee_radiance\modifier\material\glass.py"
  line 220, in from_transmittance, "C:\Program Files\ladybug_tools\python\Lib\site-packages\honeybee_radiance\modifier\material\glass.py"
  line 60, in script

Line 87 on git

^^^ that looks normal, we’d prolly see a bunch of other issues if the typing was an issue,

Line 107 in material.glass.py

also looks ‘un-sus’ imo, lets take a look at this lockedsetattr though.
line 63 lockedsetattr also looks good, it doesn’t seem to have been changed recently so that’s a good sign it’s not the issue.

hmmmmmm again specifically g_transmissivity seems to be the issue, huge chance its going to be more so localized hereabouts I think!

hmmmm I’m no radiance person but lowering the g_transmissivity value a wee bit seems to be fine
Are you sure about your input values? I don’t radiance but that’s where i’ve landed at-least on this :sweat_smile:

This is intentional since it is physically impossible to have glass that clear. If you have a transmittance that’s any higher, then the material isn’t actually glass but something else with a different refractive index.

The thing that is illegally getting above 1 under the hood is the transmissivity of the glass, which is related to the glass transmittance that you are inputting to the component but is a little bit higher than it. If you search the Radiance forum, I’m sure you’ll find plenty of topics where people explain the difference between these two.

But, in summary, if you are modeling a material that actually isn’t glass and has a higher transmittance than 91%, then you should use the HB Translucent Modifier component, which is capable of modeling this type of material.


Hello, thank you so much for clarifying the situation. I am just critically curious.
I was not aware of the difference between transmittance and transmissivity. So the Radiance glazing parameters require transmissivity and glazing manufacturers often quote transmittance. So Honeybee converts the transmittance into transmissivity.

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Yep, you got it! That’s all correct.