Fog Hybrid SSS maybe bug?

[7enith]

Hi,

I have a few issues with fog/Hybrid SSS on objects with small scale. But I´m not sure if this is a bug, an error or maybe expected behaviour.
I attached a few images for you here https://www.dropbox.com/sh/tt81emolw...5hIrJeMZa?dl=0


Its a 1m sized object with white refraction and fog color darkened so much that refraction only shows up on thin parts. Afterwards I switch on my hybrid SSS and everything works fine and expected. If I resize the object to 10cm it becomes of course more transparent. So I reduce the Attenuation Distance 10 times and things look similar to the 1m object. But after I do my hybrid sss thing the object goes black. There seems to be a hard limit where the SSS shows up or goes black. In my case it shows up until fog multiplier 1.27 is reached and it goes black with 1.28.

Maybe I missed a setting?

All the best
Christian V.

[vladimir.nedev]

Can you send me the scene ?

It might be a floating point precision problem. I did fix one such problem with the code that handles the fog, but I haven't looked into the SSS code.

Greetings,
Vladimir Nedev

[7enith]

Thanks for your quick reply Vladimir!

I quickly created a new scene which is similar. There are two cameras where you can switch between 1m and 1cm. Hybrid SSS is off on all materials and if you enable them it should only show up on the 1m material. This time the attenuation seems to behave different, I had to reduce it from 10mm to 100um to give similar results.

All the best
Christian