I created a dome shell object by subtracting smaller sphere from bigger sphere and also removed the rear half with a big cylinder object. This is done with Boolean operation A-B-C (A: big sphere, B: smaller sphere, C: cylinder).

Then I applied Gaussian surface scatter to both side surface (sig=0.25) to make some wide beam angle scatter like tis picture.

But problem when the source is moved to Z=0 where the sphere half plane is, the scattering is gone.

I guess this is caused by source being in the parent object region though parents are shifted away or disabled for ray trace. I tried moving source object below the Boolean object and entered boolean object number in “inside of” column, but that doesn’t make it work either.

I had similar issue with Boolean before when I tried making TIR lens. It was found I should avoid putting the source at the boundary of original parent object or inside. But this scattering issue with Boolean seems like new to me. Any idea if this is a bug or there is way to resolve this?

I couldn’t attach Zar file here (this forum site used to allow that, but now it doesn’t work for me), so I just copied screenshot of NSC editor.

JS