FastSSS2 and light cache

[alexnode]

Hi all,

I am an architectural visualiser, museum designer using 3ds max 2014 and vray 3.
I have a scene where I am using AXYZ people who have FastSSS2 material (They are compatible with vray 1.5 and max 2010) . Warning !!! I have never used the SSS2 material.
My problem is that near the SSS material in the final render there is noise (black dots) and after I finish calculating light cache it says invalid light cache samples.(see attachment)
I am rendering with LC+IR a high res image 4700 x 2000. Render settings are default.
I also use distributed rendering with my partner's workstation.
the settings for this material are
preset -milk whole
trace reflections
multiple scattering raytraced
Raytraced (solid)
Scatter gi off
prepass mode Single frame

I am not sure how to fix this material does anybody has a quick tip ? I have replaced it with a vrayMtl for now but i want to understand what is the problem.

[tashko.zashev]

Hi,

Thanks for attaching an example image.
Actually it will be very difficult to tell what causes those black spots without the scene file. There are many changes to the SSS2 material since V-Ray 1.5.
What are the settings for SSS2 multiple scattering ? Do you get the same issue (test in region render) if you change it?

[alexnode]

The setting was raytraced, i will try the prepass one that could work. I already change them to normal vray materials since they are far away and doesn't look different.