Zero ambient bounces for HB radiation analysis


#1

Hi!
I trying to compare the results that I get from a Honeybee radiation simulation with another algorithm and for that I want to first exclude all reflections.

I set the material reflectances to 0 and used 0 ambient bounces for the calculation. However the 0 ambient bounces seem to be giving me 0 cumulative radiation values. I would expect that I would still get the values for direct and sky diffuse radiation. Can someone explain to me why this happens?

If I am not wrong, Honeybee is using RADIANCE’s rtrace function for this calculation, and at the function description I see that an ab value of zero implies no indirect calculation.
(http://radsite.lbl.gov/radiance/rtrace.1.html). But shouldn’t I still get the direct component?Radiation_HB.gh (64.5 KB)


#2

This is correct!

This is correct for light sources. Sky is a glow material. The difference has been discussed online several times. To get started see page 20 of this documents: https://www.radiance-online.org/community/workshops/2014-london/presentations/day1/Mardaljevic_AmbientCrash.pdf

It is also discussed in this discussion on the forum:


#3

Thanks for the help! Things are slowly getting a bit more clear for me! :smiley: