Radiance: how to measure at a integrating sphere/ spherical illuminance

Hi all,

I wanted to calculate Spatial Illuminance inside the room. Instead of calculating planar illuminance, integrating sphere can account for illuminance from all directions.

I found some solutions in the RADIANCE forum: https://discourse.radiance-online.org/t/spherical-sensor/2651/4
However I kind of don’t know how to apply these codes in honeybee.

I tried using a small sphere (subdividing with triangle) / small cubic (with 6 surfaces) in the same position, is it right to use the sum of all the surfaces to represent the integrating sphere / spatial illuminance?

I believe this has been discussed on the forum before. You can use the same sensor position and generate several vectors. Here is an example that @MingboPeng posted on his website:

@tiffiena are you trying to calculate spatial illuminance like the way that Chris Cuttle suggested?
@mostapha, if that is indeed the case, then I think WELL approach is (most likely) different from that.


(PS: I have never tried to calculate spatial illuminance with Radiance, but my curiosity sure is piqued!).

Thank you for the note @sarith and sorry if I was not clear enough.

I shared the link as an example for how to generate the sensors to represent a spherical sensor. Didn’t try to reply to the post-processing part as it has already been addressed in the shared question from the Radiance forum.

Thank you Sarith!
I found the paper in your previous reply elsewhere and that is really helpful. For the method to calculate cubic illuminance is mainly used for radiometers with length as 10 cm, I’m trying to find some solutions using sphere or mesh with (possible) higher accuracy. When I have some updates I will post here!


Thank you mostapha!
The research done by Mingbo is interesting too. It’s always exciting to find new potential in ladybug tools :slight_smile:


Hi @mostapha, after I read your answers, I have been trying to solve this problems these days. Since I’m new to script and coding, could I ask one more question?
About the code I found in the Radiance forum ( https://discourse.radiance-online.org/t/spherical-sensor/2651/4), could you please tell me where I can paste the code to modify the raytracing recipe? I’ve installed Honeybee+ and found the rcalc.py or rtrace.py, but they don’t seem like the right place. Thank you so much! I’m really struggling with this and can’t find answers online…