Using LARK 3.0 for CS calculations

Grasshopper
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1

Hello,

Understanding the below is a niche question regarding circadian lighting and apologies, these workflows are a bit new to me so making sure I don’t misinterpret the science.

Using the new LARK v3.0. Wonderful tool (New version of Lark Spectral Lighting Grasshopper plugin). Using point-in-time workflow per the tutorial, I’d like to try and convert some of the outputs (which would include all spectral, reflectance, and room based illuminance data) to Circadian Stimulus (CS) using https://cscalc.light-health.org/

I see the text description in the script but this is due diligence: does the output that comes from the 9-channel CIE Toolbox section - irradiance represent the combined vertical spectral power arriving at each point? Meaning, the CS tool requires a SPD and illuminance as inputs. Could I export the irradiance from this tool and the illuminance of the point and plug this into the CS calculator to get a reliable value? CS itself is not additive but I’m hoping combining the SPDs in this way through analysis would streamline the CS toolbox step.

I tried and you do get a result but not sure this is an acceptable workaround.

image
image1920×1111 190 KB

As another note, the CircaLight plugin seems to take care of this workaround! Excited to try it (CircaLight, a new circadian light assessment tool for Grasshopper environment: Development and reliability testing - ScienceDirect)

lark_template_point_in_time.gh (1.4 MB)
SampleRoom_PatientRoom.3dm (1.6 MB)

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Hi Reinhardt,

Yes, you are right. The irradiance output from the CIE Toolbox component provides you with the absolute spectral irradiance in W/m2/nm (every 1nm between 380 and 780). Whether it is vertical spectral irradiance depends on how you defined your sensor in Grasshopper, but assuming a horizontal view direction/vector, you would indeed get vertical spectral irradiance.

The CS calculator can work with either an absolute or relative SPD, so yes, you can definitely use that absolute SPD output directly in the calculator to create a custom source. You would then only need to provide the corresponding photopic illuminance (also outputted by Lark) to the calculator to get your CS value.

Thank you for the question and comment; we should definitely add a new component in a future release to derive CS as well!

Clotilde