Michael314 wrote:Hi Uwe,
Ok, so the depth of the scattering is then determined by the division of the scattering setting and the scale? I used 0.5 where you have 0.09.
I found the value of 50 through trial and error (best item to look at were the hands, I tuned the parameters until I got a slightly reddish effect on the fingers but not on the palm).
I read through your post and I agree that the color of "transmission" is crucial - with everything else same, this can give you anything from a yellow-ish ill-looking face through normal and towards a blushed appearance.
In the picture attached (DAZ Reby Sky model), I used a map for the transmission color (EC). I first tried to use the transmission strength maps (ES) as well, but then through that Octane would give me that though volumetric effects (material thickness), which I think is not available in the programs they made the maps for.
Michael, your values are way off.
The exact calculations and settings are explained here:
http://render.otoy.com/forum/viewtopic.php?f=21&t=9380&p=67650Without a decent setting of the transmission channel you won't get a nice SSS effect:
You'll need a grayscale SSS-Map (which can be very rough and lo-res, like 512X512) which defines what regions of the body are affected by the scattering (like Paul said: nostrils, ears, fingers). You can go without it, but then you'll get an overall waxy impression (some still might take for a wonderful skin, anyway
).
Multiply this with the color you need to have for the effect (I used a pale red, could be made something more saturated, probabliy)
The medium node tells how "deep" the light rays travel into the object, and how they get reflected. 9mm seem a reasonable value for me, though the effect gets stronger the darker the skin color is, so a fine tuning between 12mm (very pale skin) to 4mm (very dark skin) might be required. Skin sub surface doesn't reflect too much light in the direction it comes from, the main part goes
through it (again, see the ears!), so the direction value has to go more to +1.
I have to disagree with Paul about the absoption. With the right transmission, scattering and directional values you don't need to touch the absobtion and can leave it to 0.0.
And, of course, you have to render in pathtracing or pmc
I've attached 3 examples with different diffuse and bump maps, all other settings like transmission, SSS or specularity are unchanged (note the impact of the effect):