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.

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.