Can we simulate the daylighting levels with a shorter time step of 1 minute using honeybee?

Hello Everyone, @chris @sarith @mostapha

I want to simulate the annual illuminance levels for a space. Since the weather data contains only hourly values, is it possible to simulate the illuminance values with a 1-minute time step by using honeybee?

I have read a paper ( which talks about a stochastics process to get a shorter time step data. The process described in the paper sounds so technical for me.

So is there any easy way to get shorter time step illuminance data in honeybee itself?

Reference: This thesis by Christoph Reinhart ( also talked about generating a shorter time step illuminance data in DAYSIM.

Thank you,
Tarun Verma
PhD Scholar NITT

Hey @tarun0949 ,

There’s no support for this in Legacy but Honeybee[+] 0.0.06 can do it. You’ll see that the “WEA from EPW” component has a timestep input on it, which will allow you to run the simulation at timesteps finer than an hour:

The component only does a linear interpolation between the illuminance values of the EPW, though, so it’s nothing fancy. But this type of linear interpolation is basically what EnergyPlus does, so this can be particularly useful if you are trying to align a Radiance simulation with an E+ one.

If you are ambitious enough to make your own sub-hourly .wea file, there are also ways of easily integrating that into Honeybee simulations using the Ladybug Tools SDK.

Hello @chris

Thanks for your quick response.
I have tried using the “WEA from EPW” component to generate a shorter time step data. But this component did not show any outputs for me at the same time it did not show any errors as well. I don’t see any problems in my script and I even tried this with 2-3 epw files but the problem remains the same.

I am uploading the grasshopper file for your reference. Please check. (462.1 KB)

Thanks and Regards.

Hey @tarun0949 ,

Everything under the hood was working correctly and there was just a small issue with the “Deconstruct Wea” component. I just fixed it and you can see that it interpolates the Wea correctly in the attached file: (466.0 KB)