As shown in this image. I put an opaque block behind the SSS wall to block the light, but it doesn’t do anything.
I don’t recall this is the behavior of SSS in UE4, is this a known issue in 4.4.1 or I’m just hallucinating?
The light being used is Move-able Spotlight that cast shadows.
Any ideas?
Thanks in advance.
Hey RinDreamX -
I have been looking into this and haven’t been able to reproduce the issue you are having. Could you post a screenshot of your material setup including a look at your material attributes settings and a look at the spotlight’s details panel as well?
I would also begin by looking at your opaque block and light radius and make sure that the cone of your spotlight and its attenuation radius encompass both block and subsurface plane. It looks like it does in the screenshot above, but its worth mentioning as an easy and often overlooked solution.
Thank You
Eric Ketchum
Hope this screen clarify a bit more.
Essentially it’s very basic 0 Opacity SSS material and Opaque material as a shadow caster.
The Spot light is movable and cast shadow.
In the shot no: 4 I disable inverse square, but it shouldn’t matter and both did exhibit the same problem.
Thanks for looking into this issue.
Forgot to add, setting the light to Cast Translucent Shadow also didn’t solve the problem 
Hey RinDreamX -
Remove the 0 opacity and your SSS will work as you wish it to. Having a zero in opacity is telling the material that it will hold no shadows (its functionally translucent in relation to the shadows cast - nothing to cast on).
Thank You
Eric Ketchum
