Trouble replicating Radiance results with diffusive materials about pbrt-v4 HOT 2 CLOSED

PD: I asked Greg Ward—developer of Radiance—and he told me to check my sampling and pdf values for checking the Montecarlo integration. I integrated a hemisphere of value 1, and found the expected answer of Pi; and by integrating a unit overcast sky (i.e., L=(1. + 2. * cos(theta))/3) gives me the expected Pi * 7/9. I guess the error must come from elsewhere.

I'll keep digging!

from pbrt-v4.

All right. I have solved this issue. As it happens, my implementation was correct apparently, but some of the Radiance parameters I was using prevented it from accounting for the last bunch of—low-energy—bounces. This was particularly noticeable in one of my scenes, which had a 90% reflective surface (to take into account these things)... I guess there is a lot of value in my new implementation, based on your work: it has less and more predictable parameters.

from pbrt-v4.