Sub Surface Scattering Question

[mitchino]

I'm creating a matte plastic cap and have set up a specular material with a scattering medium node going into the medium slot. I have a dark green in the absorption slot and a light green in the scattering slot. Fake shadows are on, rendering using PT.

Why are the edges of the bottom part black? Can I fix them?

[mitchino]

another zero in the ray epsilon settings did it

[bepeg4d]

This is normal, Ray Epsilon is the precision of the rays, so, if your object is too small, or too big, compared with the scale of the scene (normally in cm), you need to correct the Ray Epsilon value, or correct the scale of the scene.
ciao Beppe