I found this problem in C4D at first, see this post: https://render.otoy.com/forum/viewtopic.php?f=9&t=80923&p=419965#p419943
Anyway it looks like a weakness on Light rays which are blocked by self at zero angle between faces. You may export ORBX and post in standalone topic
I then exported the ...

aoktar wrote:Anyway it looks like a weakness on Light rays which are blocked by self at zero angle between faces. You may export ORBX and post in standalone topic

Thanks, I will.

Additional Info:

Area light noise on the side is difficult to remove
This is the result of 3000 samples from the PT engine This is the result of rs double brute force automatic sampling 0.01 So is there any way to render noise cleanly without denoise?

Through many projects I found Octane‘s materials always end up a mass,
I always struggle with a bunch of Mix materials, especially when duplicate them,
a lot materials need to rename and the links in the Mix materials' parameter need to be replaced.

So I write a group of scripts to make it easier ...

OctaneRender for Cinema4D 3.00 - R1
the Dirt shader can`t not work in the emission texture nolonger,it worded well before in 2.25-R2