in this lesson we will take a look at
the all surface material an incredibly
realistic looking skin shader and
explore how to use it while harnessing
the enhanced speed of GPU rendering the
v-ray all surface shader is furies
implementation of anders Langlands all
surface shader which is designed to
reproduce the appearance of skin the
current v-ray version takes into account
diffuse two levels of reflection and
subsurface scattering in this scene we
have a model of a female head and some
preset studio lighting setup the shaders
for the eyes and hairs are already
applied and we have displacement on the
base mesh of the head for finer details
to get started let's open up the
material editor and create a v-ray all
surface material
for an easier workflow I'm going to set
the diffuse to a darker gray with a
value of 80 this way the reflections
will be more visible during the look
development process also let's make sure
that the subsurface scattering mix value
is set to zero then go ahead and change
the value of the reflection one strength
to zero so that we have just diffused
information coming from our shader by
starting with a simple setup like this
it's easier to build up our shader and
understand how each parameter is
affecting the overall result as it
increases in complexity okay
now let's apply the all surface shader
to the model and then open up the v-ray
settings let's make sure we're on v-ray
GPU next then go ahead and start the IPR
so we can begin working on our skin
shader
for a faster preview I will also draw
render region so that way we can quickly
observe and compare the changes we make
to our material now the first thing I
would like to cover here is the bump
texture parameter of the material let's
load our texture using a v-ray HDRI map
this way the bump texture will be loaded
in the correct color space without any
additional setup I'm going to load in
the zero zero displacement micro EXR
and for the bump texture I think a value
of 10 works nicely for this scene using
the bump texture slot for the all
surface material we can control the
overall bump of the shader but I would
also like to have even more control over
that parameter as a result I will
connect our bump texture to the diffuse
bump texture slot and copy the bump
strength value of 10 from the overall
bump
now we can move on to setting up the
reflections we will use both reflection
layers to better simulate the surface of
skin let's start with reflection one
I'll set the strength to one the
roughness to 0.65 and the IOR to 1.6 I'm
also going to switch the brdf type to
ggx
which will recreate a surface with micro
imperfections the better suits our skin
material now we need to add the bump by
connecting our bump texture into the
reflection one bump texture slot let's
also set the value to 10
okay the reflections are a little too
blurry and spread out than what I'd like
them to be so I'm going to lower the
roughness value to 0.55
okay that looks better all we need to do
now is lower the strength a bit as the
material looks too reflective at the
moment something like point eight should
work
okay now let's head to the second
reflection layer which will simulate the
thin layer of oil that skin naturally
has since this layer needs to be shinier
than the skin itself I'm going to set
the reflection to strength to one the
roughness value to 0.4 and the IOR to
1.6 again let's also set the brdf type
to ggx as well
okay that looks good but we still need
to add our bump let's connect the bump
texture to the reflection to bump
texture slot and set it to a value of 10
all right I want these reflections to be
spread out a little more so let's
increase the bump value to 15 now I also
want to bring back some of that glossy
look that we had before so let's also
lower the roughness to 0.3 now I think
that we are going in the right direction
but the reflection layer too is still
coming off way too strong let's lower
its strength value to 0.4 and then we
can move on the next important aspect of
a skin shader is the subsurface
scattering which affects how the light
scatters underneath the skin surface we
can turn this effect on by setting the
subsurface scattering mix value to 1
you'll immediately see the effect as the
surface of the shader smoothens out and
a slight reddish glow appears which is
controlled by the subsurface scattering
color parameters below now we can get a
sense of the thickness of the skin in
different areas especially where the
skin is very thin like around the
nostrils the default subsurface values
of the all surface material are pretty
good at creating realistic looking
results but let's see what happens if we
tweak some of these parameters further
for example in the first subsurface
layer let's increase the scatter radius
to something like 15 higher radius
values will scatter the light further
distances within the subsurface
scattering layer this immediately
changes the feel of the shader as
everything becomes smoother looking and
you can now clearly see the light
scattering in the skin throughout though
it looks cool this is not the effect I'm
going for as the material now looks more
like wax rather than skin so let's bring
the scatter radius value back to 1.5
okay great now that we've explored how
to set up the correct reflections
roughness bump and subsurface scattering
all we need to do now is add a diffuse
texture let's create a bitmap texture
node
and then load in the diffuse texture for
this model from the assets folder and
then turn off the render region and let
v-ray render out the final image
all right now you've seen how in v-ray
next you can use the all surface
material on GPU to create
physically-based skin shaders while
harnessing the power and speed of GPU
rendering