Shouldn't SSS work as a volume taking in consideration other geometry inside or on top of it when calculating internal shadows?

If have a sphere with SSS and a cylinder crossing inside of it I can't see the the shadows of the cylinder inside of the sphere ou if I have this same cylinder behind I also can not see the shadow through my sphere, it doesn't seem to interact with anything else besides itself.

Am I missing something or this is normal behavior?

Thanks.

Hi, you're not missing anything. The BRDFs currently used for SSS do not sample the volume of an object.
You may try to add the same geometry as a volume and have the surface geometry with transparency. IIRC the ocean tools or some flip shelfs provide an example setup.

There's also the physhader [github.com] which has a utility node to check for objects inside objects. This helps with (lower resolution) volumes not sticking outside of the surface.

I hope this helps.

Andy

Thanks for the info dude!

Cheers!

Andy58 is correct. You'll need to use a volume shader. Most implementation of SSS are approximations based on irradiance on the outer surface (ie the surface that's directly visible by the light).