Hi @ZheKong ,
The 3 RGB channels are something that is built into Radiance and so there are actually values for them in the Radiance simulation but we just average them together at the end to give you the overall illuminance.
Granted, both for Legacy and LBT, the difference in the RGB values is meaningless because the sky is rendered in greyscale and all materials of the honeybee objects are grey by default. So, for the RGB values to be meaningful in either Legacy or LBT, you will need to first generate a colored sky. We have an open issue to support colored skies:
It seems like it’s generally a pretty quick thing for us to add to LBT 1.6 thanks to the sample @sarith posted here:
But, in addition to that, you would have to assign modifiers with real RGB values to all of your Honeybee geometries.
After that, you will be able to see the colors of everything coming through in the simulations that you run with HB Point-in-Time View Based recipe. And the values that you get in the HDR image will be suitable for circadian studies. So I would start with view-based studies and, if what you get in the images is making sense, we can probably help you get the RGB values from the grid-based studies.
If you have a model with colored modifiers ready to go, I’ll see if I can add the colored skies later today.