Subsurface Scattering Pa=
rameters
Enable
On by default, but if off, the next lowest layer (or base) lobe is used.=
Gain
Subsurface scattering weight. Higher numbers increase the visibility of =
the subsurface scattering.
Color
Subsurface scattering color.
=
Mean Free Path Distance
Subsurface scattering mean free path distance (mfpd). This specifies how=
far the light travels inside an object and as a consequence how smooth the=
subsurface scattering is. This gets multiplied by the unit length set in t=
he Properties section. Higher amounts make the object appear less opaque an=
d more translucent as well as increase noise. Small amounts make the surfac=
e look diffuse and it may be more efficient to turn off the effect (0.0 Gain) if it's not visually important. Below we change the val=
ues from 8 to 16 and then 32. Notice how the sphere and pedestal become "so=
fter" and more translucent. Your render times might also increase at high v=
alues due to noise generated by translucent objects.
=
Mean Free Path Color
How far the light travels in the Red, Green, and Blue spectra. This is s=
caled by Mean Free Path Distance. Different colors may spread more or less =
and provide interesting effects like the red color bleeding into shadow edg=
es on skin. The RGB values correspond to how far the light travels in that =
color band. For example, and RGB value of 0.8 0.65 0.5 means Red spreads fu=
rthest at 0.8, then Green and finally Blue traveling the least distance in =
the object scatter result. Below we've taken out the center sphere and repl=
aced it with a bright disk light at the back of the outer sphere. Note that=
the sphere and pedestal share the same material and lighting play=
s an important role in your result.
=
=
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Post Tint
Tint that is applied at the end of the subsurface computation. Below on =
the left is a normal render and on the right a very light blue tint is adde=
d. If we want to apply the tint before the subsurface computation, set Irra=
diance Tint in the Properties section.
Multiple Mean Free Pat=
hs Description
Multiple Mean Free Paths operates differently than the =
others in a few significant ways. For most cases you will be happy with the=
results of the other models. However, there are instances where the user m=
ay want a non-physical way to control the colors of the scattering. The Mea=
n Free Path Color in many models uses the supplied RGB value to determine t=
he color scatter as noted in the parameter description. This means your res=
ult may have color shifts that are not desirable. Let's say you supply a te=
xtured color of RGB 0.51 0.28 0.31 which is a pink color. The scattering re=
sult will also include the green (0.28) and blue (0.31) responses. The Mult=
iple Mean Free Paths model maintains the pink color. Below is an example us=
ing this scenario illustrating the differences. The texture is connected to=
the Color and Mean Free Path Color of the Jensen Dipole and to the Short a=
nd Long Colors of the Multiple Mean Free Paths model in addition. Note the =
color shift on the Jensen model (Left) while the Multiple Mean Free Paths v=
ersion maintains the colors of the texture at all depths where connected.=
p>
Short Gain
Short subsurface gain or weight. This is only valid for Mul=
tiple Mean Free Paths subsurface model.
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Short Color
Short subsurface color. This is only valid for Multiple Mea=
n Free Paths subsurface model. Above uses Red as the chosen c=
olor.
Long Gain
Long subsurface gain or weight. This is only valid for Mult=
iple Mean Free Paths subsurface model. Operates the same as <=
strong>Short Gain.
Long Color
Long subsurface color. This is only valid for Multiple Mean=
Free Paths subsurface model. Operates the same as Sh=
ort Color.
Short MFP Distance
Short subsurface mean free path scalar distance. Below we go from 16 to =
24 and finally 32.
Long MFP Distance
Short subsurface mean free path scalar distance. Below we go from =
16 to 24 and finally 32.
Transmit Gain
This only applies when Double Sided is on. Instead of usi=
ng the Subsurface Gain for controlling the intensity of th=
e subsurface transmission, we use the Transmit Gain. =
If it's 0.0, then the effect is off.