All language subtitles for 01. Simple Skin Material.2

Welcome to another blender cookie
tutorial my name is catcher mail

and in this video we're going to be taking
another look at realistic skin shading

with blender.

So far we walked through
this subject twice already.

Once in depth with the blender internal
render engine in the realistic head series

and then we briefly
touched on it

with cycles as in the
pancake hobo course.

But thus far we haven't gone in
depth with skin shading in cycles yet

so that's what i want to do.

Now if you've watched any of my training
before hopefully you know right away that

the first order of business is
taking time to observe reality

and for human skin this
is especially necessary.

Because everyone see human skin every day
and subconsciously knows precisely how it's

supposed to look.

That's why it's so hard for cg artists to get
right because if it's the slightest bit off

we all can tell and
the illusion is broken.

However understanding why human skin
looks the way it does is another story

knowledge that isn't so common.

So please study as many reference for
autographs as you can if you want to create a

believable skin material.

But since i have gone over skin observations
before in the pancake hobo course.

I'm only going to
hit the basics here

but if you want a more
detailed explanation

please go see the skin
lesson in that course.

So the buzzword when
it comes to skin shading.

Is subsurface scattering

and this is basically a
fancy term for translucency.

If we take a look at
this reference photograph.

It's a very typical
studio lighting setup

with very harsh back and rim lights which
are pushing a lot of light through the ear

here and this is

typically when it comes to
subsurface scattering and human skin

most people look straight at the ears
because that's where the effect is most

noticeable and you can get
a very bright orange red glow

and this color is what
bleeds through the shadows

and softens the shadows.

Notice here at the nose.

If we zoom way in and then if i
just right click and hover over.

The edge of our shadow

notice just how red the color is

that's actually happening on

all the shadows across the skin

and this is the key thing that i want
you to take away from this observation

and that we will
need to recreate

as we pull back out in general

the effects of sub-surface

causes a softening of the shadows
and therefore a softening of the skin

detail

and as far as the orangish
red color that is coming from.

Different layers underneath
the surface of the skin

like blood like muscle and
fatty tissue that combine

to give us that color as
the light scatters through it.

And with all that in mind

let's jump into blender and take a
look at the assets we have to start with.

So this comes from a
personal project that i

did a couple of years ago.

It's a slightly stylized and

elderly man head

and the reason i want to use this
is number one there is a ton of detail

built into the geometry

through a multi resolution
modifier up to level five.

If we jump up to
that level you'll see

all the skin and pore
detail that I've included

in the actual geometry.

You can

see how heavy it is.

Considering the viewport

sluggishness now

and it's important that this
is included in the geometry

meaning that it's
breaking the silhouette

it's not only included in a bump map
or some kind of cheat but it's actually

affecting the shape of
the geometry this will

help to ensure

a more believable.

Subsurface scattering effect

so let's pump that back
down to let's say level two.

And along with
this very detailed.

Piece of geometry

i also have.

All the texture
maps that i painted.

Specifically for human skin.

Things like.

Epidermal texture map
and subdermal texture map.

Bump maps subsurface
scale maps specular maps

all the textures that i would
need for a realistic skin shader

have already created it just needs to
be plugged into a shader appropriately.

So before we actually create the
shaders let's go through through.

The render setups that i have i'm just going
to split my user interface over here to

give me a very small.

Render viewport

and i should have a camera
let's at zero there you go.

Making sure that i'm in the cycles
render engine I'll go ahead and enable.

Viewport rendering or
shift z in that viewport.

And we have a black silhouette
because i have no lights visible

so let's jump over to my

layer management
add on and enable

layer rin a.

Which is my firm
first lighting scenario.

Pretty standard stuff with.

A strong key light.

A.

Back slash rim light

and then.

A large card which acts as a sort of
global rim light that i will show up

particularly well.

With reflections

and then then let's go
to the next one rin b.

This is a actually
very similar except that.

I would change the world
value so let me go choose a

environment map.

I will of course

include some environment
maps in the source files.

And do

ok so if i bump this up
to let's say point five.

Now we have a lot of environment lighting
contributing to our shadows lightening them

up a whole lot

and then finally we have
render scenario rio see.

Which if i

let's say turn off my
environment light again

this setup is useful for looking at
how back scattering works through the ears

and if

my sub surface values are good.

So yeah the reason
i show you these is

in order to get the best

skin material.

You'll want to look at the shading
through different light setups

and if it looks good in all the lighting
situations then you can have confidence

in your material.

So i think I'll start with

scenario a.

Just because

it's a little bit more
neutral and standard

and let's get started
building materials lrs.

I'll switch my

three d viewport
to the node editor

with the n key

and right now i have
one of my cards selected

but if i select my
head geometry over here.

We have no material
associated so.

Let's create one

and i'm going to call
this skin underscore simple.

Because i'm going to walk
you through a couple different

skin shading setups

obviously i named this one simple so the
first one is going to be a fairly bare-bones

approach just using the
subsurface scattering node

and textures associated
with the model

and then after that I'll
show you a more complex

approach to sub surface
scattering specifically for skin.

With Matt heimlich support
of the Arnold skin shader

which has all the bells and
whistles of three layer skin shading.

That you may be familiar
with if you come from the re

mental ray.

Are obviously Arnold

but being more complex

means that it actually rings
hers about half the speed

as the simple setup

and you can actually get a very
believable result with the simple setup but

still i think it's
good to know both ways.

So now let's introduce our
subsurface scattering node with shift a.

Shader subsurface scattering.

And we'll remove
our diffuse b sdf

and plug in the bss rdf
output into the surface input.

And immediately we
can see in our viewport.

That.

Way too much light is now penetrating
the surface and scattering around

it's glowing way too much

so the first setting i usually tweak is
going to be this scale value right here

where the higher the value

the easier it is for light to penetrate
and the further through the surface it can

penetrate

the lower the value.

The harder it is for
light to pass through

the surface and it
doesn't go quite as deep.

So let's bump this down.

Two point one.

And you'll see that

less light is able to make it all the
way through the ob checked and our shadows

appear

and if we go

down a little bit more let's go
two point one five cut it in half.

Our shadows get even darker and more of
our model starts to appear while we still

have a lot of light
shining through especially.

In the ears

because they're the
thinnest part of our head mesh

but that's still a
little bit too high hi.

How about a point one three.

I think that's going to
be a good value based on.

My exploration of this shader

and now with that dialed in it'll be a lot
easier to go over these settings which i

will quickly

run through first we have.

The fall off algorithm
that we can select.

Where i kind of look these in reverse
order from bottom to top where compatible

is the old algorithm that's about to be
phased out and removed from trunk so we don't

need to worry about that at all

and we're going to be
left with cubic and goshen

cubic is a sharper fall off
based on the documentation

and it actually renders
a little bit faster

but then

goshen is slightly more complex
of an algorithm so it takes

a little bit longer to render but it's
perhaps a little bit more physically accurate

though when i compare the two i really
don't see any noticeable difference

aside from a slight render time savings
with cubic's i'm going to select that it is

the default or it should be

a below that we have color this is
the general color of our object so if we.

Do let's see switch that
too let's see zoom out here.

Switch that to green

you know it looks like a
green object that scatters

which is probably pretty obvious to you
of course that's what that does but with

subsurface scattering if
we jumped down we've always.

As the scale option here
below that we have radius

and

this is where we control.

What color the
scattered light becomes

so if you remember that
reference image we just looked at.

In the shadowed areas on the edges i pointed
out how red the shadows were and this is

the scattered color glowing through the sh
shadows and with skin it happens to be red

so if we open up those options we have
three values with a really no description

but the first one
is the red value

the second one is a green value
and the third is the blue value so

rgb which gives us

an overall color.

So again with skin we're looking
for a row red color so let's leave

the first value at one

and then start to decrease the green and
blue which should leave us with more red.

So let's

bump these down to half
point five point five.

And you'll start to see that we get
an overall green color of our object

but the light
that passes through

causes it to glow low read

and i think i want it to be a
little bit more orange let's.

Remove the green color take
saturation all the way down to zero

and.

Okay yeah so i don't have any green
interfering and it's clearly a very red color

so in the radius let's.

Bump down my blue value.

So now we have a lie little bit
more green in the mix which should

take it closer to orange or
if i bump that up to point six.

Yeah we're starting to get.

A little bit

closer to orangish yellow

but still mainly.

Red.

All right i think that's good for the radius
that is a very important setting i would

say radius and scale
are the most important

but we have a
couple more options

below radius we have sharpness.

Now.

What i can tell sharpness does

is kind of the same
thing as decreasing scale

but just to support my theory on
what it does let's go ahead and do.

A couple renders

number one we will
render this with

sharpness turned off.

Then let's

switch to let's
go to slot seven.

And.

Go back to the node editor

by hitting escape

and

let's change our sharpness all
the way up to a value of one.

And render that again.

And now if we switch
between slot eight

and seven.

You can see

in slot eight.

That.

The details especially in
the forehead around the eyes

and will generally the front of
the face it gets a little bit blurrier

but then.

At seven they sharpen up a bit.

But also there seems to be more light passing
through the ears the glow gets a little

bit bored brighter.

So on

changing the sharpness setting
is not exactly the same as.

Simply dialing down the scale

but

it's some sort of in-between
that tries to sharpen

the details of the geometry

while still maintaining
that scatter amount.

And jumping back
to the node editor.

I usually leave sharpness off.

Because i.

Kind of think it detracts from
the believability a little bit

but abelow that we have texture
blur and this really only.

Is noticeable when
we're using a texture

because it does exactly what you
would expect it blurs that image

and the idea behind this
is if you read the docs

it states how and.

For example if we used a
photograph to create our textures.

It's already blurred there's
already blurring happening

within the sub surface effect because
the picture is of subsurface skin.

Whereas if we hand paint a texture
we might not necessarily build that in

and especially if we use a

procedural

we'll want to blur based on the
subsurface scattering algorithm

and that's really where this comes in handy
so i rarely ever touch the texture blur

setting.

And that is all for the.

Features of the
subsurface scattering node.

Do note that if
we switch to goshen

we lose the sharpness option.

Which again lends itself

to me believing that sharpness is
more of a cheat effect rather than being

physically accurate

but

anyway other than that that's.

All all for the
subsurface scattering node

and we're ready to plug in our textures
so i'm going to add an input texture

coordinate node.

Way over here off to the left

and then add input.

I'm sorry not input
texture image texture.

First we're going to load

and

our general head.

Color texture

let's enable thumbnails so we can
see exactly what we're looking for.

This is what i want
head color right here.

And then

let's plug in our
uvi to the vector.

And the color of our image into the
color of our subsurface scattering node.

And right away

you know it looks a
little bit more human

though.

In general the whole texture
feels a little bit too orange.

So

let's

add.

A.

Letter see color

rgb curves note

in between the image.

Color output and the
subsurface scattering node

and for the red channel.

I'm going to take
the right upper corner

and just drag it
down a little bit.

Then jump to the green channel

and drag that down
about half as much.

Yeah that feels a
little bit more natural.

Maybe a little less

red.

Air ago that feels better

and that's really it for having

a texture plugged into
subsurface scattering color

but we can also use textures for
everything else so i'm going to show you

what a scale texture does and

with shift control d.

To duplicate the image texture node while
maintaining the connection to the texture

coordinate node

and let's go open
another texture.

That i have already created and i have two
different versions of this it's called ss

as scale and ssl as scale beep.

Now scale b was procedurally
created by simply inverting

the head mesh and then baking
an ambient occlusion map.

That will conveniently
give you darkened areas

around the thinnest
portions of the mesh like the.

Ears

the eyelids the nose
and lips which is

you

if you want to control the scale that's
where you're going to want to control it.

Sounds pretty cool but
this first one is what

I'll use and it's
just simply hand painted

around the.

Ears and the eyes so
let's go with that one.

Both of them will be included in the
source files for you to play with but.

Ok so now if we plug this
directly the into the scale value.

There will be absolutely
no subsurface taking place

in the majority of the
head as you can tell but then

the eyes which is painted
to be point five value gray.

That has

a scale of point five so we see scattering
there and then we see a lot of scattering

around the ears.

Which of course doesn't look realistic
at all so we need to dial in that value

and mix it with a shift a color.

Rgb.

Art mix rgb node

and let's.

For the top.

Color swatch

i'm going to copy the scale value
that i was happy with point zero three

have moreover it hit control c

and then click on the color
swatch and for the value.

Let's paste that in there.

And then for the
operation let's choose add

because it once i
add the color from r.

S as a scale texture.

It will allow any areas that are
black will add nothing to this value

so the majority of the
head will stay at point.

Zero three

and then anything above zero will
simply be added increasing the scale

allowing more light
to scatter through it.

Like the ears which is what we
want so let's plug in the color to

color swatch number two

and then plug the color
into the scale value.

Giving us continued

surface effect all over
the mash but it's much

more concentrated in
the ears and the eyes.

So here's where we
have the option to

adjust the factor

and dial in how much of
that scattering that we want

so let's go way down
let's go to point one.

And that's still too much
how about point of two.

Erykah

you know that's a
little bit better

and

certainly easy to dial in if we want
more scattering in the ears which is.

You know something common that

people like to do.

Let's see here i wonder
how we're looking with

our other.

Lighting scenarios.

Let's disable render a and
take a look at render be.

Yeah that looks pretty good
from that angle how bout.

C which is basically
just a backlight

it's still looking good still
looking subsurface scattering.

So that's.

Great I'll stick with.

Render be for a little while

i think that's my favorite.

Lighting setup

and jump back over
the node editor.

Because the only component
that's missing from my

simplistic subsurface.

Skin material

is the specular component.

So if we add a shader.

Glossy b sdf.

And then mix it

lets the shader mix shader node.

Mix it with our sub surface.

We'll start to get some reflections
which are certainly a necessary part

of a skin shader.

And

i'm going to sound like a broken
record but with reflections comes for now.

So let's create
that component now.

Shift a input.

Layer weight.

Shift a vector er.

Let's see

not vector i'm sorry converter

color ramp.

Plug in our facing value into
the factor of our color ramp.

And just to

let's see dial this in

let's plug it into an emission
node first before using it.

To control the factor
of our mich shader node.

There we go let's switch our interpolation
to be spline and drag our lower.

Dark flag up.

Yeah to be like that

and now plug this into.

The color output into the
factor value of our mix shader.

Plug that back into the surface.

So we can see our
specular component now.

I think that's looking
a whole lot better.

But.

I will i'd like to take
this one step further

and also use this color rant
to control the roughness value

of our glossy b sdf so that.

As our geometry faces
away from the camera

which is increasing the amount of the glossy
be sdf which is why we get this nice rim

light

i also want it to.

Decrease the roughness
value making it

more shiny.

So let's add a color mix node.

And let's make the top

color swatch the value of the surface
that's facing more directly at the camera.

Change that to point.

Three.

And then

for color swatch number
two let's change that

to be

much lower to be more shiny

and let's try point
o one for that.

Than the color of our color
ramp goes into the factor.

And this color goes
into the roughness.

And then let's do a test with
and without at first without.

And and.

Oh

okay i messed up

i messed up something
let's go back.

I also need another mix node
like this one to control the factor.

A little bit more because

right now it's black.

You know for the faces that are.

For the surface it's facing
the camera more direct early

so there's no reflection
happening which is

clearly not.

Accurate

so we'll plug that color ramp
into the factor of another mix node

and the top value

needs to be let's say point one
and then the bottom value needs to be.

Point.

Let's go point five.

That might be a little bit
strong in both areas let's go.

Point three in the bottom

and point

o five

in the top.

Yeah let's give that a shot.

There you go that's much better.

With the.

Glossy clearly showing up on the

front of the forehead front
of the nose and also the lips.

That's certainly helping

our skin out.

That's without the roughness
maps now it's jumped to slot six.

And plug in our mix node.

For our roughness value.

And render again.

And here we have a much.

More subtle glossy effect

but this is how we can control.

How sweaty our character
is so if we go to slot seven.

You know he looks a little bit shiny
or a little bit more sweaty slot six.

Not so much.

So we can tweak those values i
think i i would tweak the values for.

Let's see the upper slot to be let's
see point two five instead of three.

And then maybe increase
the factor how much.

How much gloss is being added.

Right now the value is a point
o five i would increase that

let's see I'll actually increase
that two point one double it

and then leave
the roughness as is

at point three.

And then perhaps bring in a little bit
more reflection on the sides of the head.

With this bottom value over here
from point three let's go to point

four.

Yeah i think that's pretty good.

Do one more render.

Jumping back to the.

U the image editor.

Let's put this in slot five.

Yeah i think i'm
pretty happy with that.

Switching back to slot six.

Then slot five.

More reflections.

Or higher gloss value.

On top of the sub
surface i think works good

what we want is a nice
balance when it comes to skin

wear with subsurface.

The detail sales will be washed
out basically that's how it should be

and the way we get
them back is with

you know specular reflections it really
gives you a sense of the depth that the light

is penetrating

so that's definitely a key part is
striking the balance between specular

and subsurface.

But yeah that's you know
essential really all of my

components for the simplistic
subsurface shader using the.

Subsurface node

and if we go back to
the node editor and.

You know i have

all kinds of places
to plug another map in.

For example.

Let's add a bump map

shift control d

my image texture sure.

Go grab that.

Texture map

sss bump right here.

And to test this out

let's unplug our color from the
subsurface scattering node and leave it.

A whoops that was the
scale let's unplug the

color texture

so that it's white and at this
point i need to do render previews

at a higher resolution
to see more details

i'm going to bump that
up from fifty percent

of the render rez
two hundred per cent

and also increase
my samples well.

No i won't do that
quite yet i still want

you know.

Optimize renders
for the previews

and

anyway so the bump map is going to be
plugged directly into art displacement output

of our material

and.

How about we make a little
bit more room over here.

Right away i know that my bump
is going to be way too strong.

Or at least usually it is so let's try
doing a render as is and see if we need to

dial the bumped down at all.

Okay it might be kind
of hard to tell because.

It's still a fairly
grainy render.

That's another thing about subsurface
it needs more samples to clean up

and since my bump map
is a basically poor detail

you can't tell the difference
between pores and noise.

So

i also didn't render

a

before comparison so let me do
that real quick before we start to

dial in

the

button math

jump to slot five.

And.

Disconnect the
bump image texture.

Here we go here is before

four is after.

So.

There's quite a large change

and it's almost
like the face sort of

mushers and melts a little bit once the
bump is applied and that's because the bump

is way too strong.

So let's jump back to
our note editor and add

a a.

Converter math node.

Where we can plug
our bump texture into

here's where we can change
our operation to multiply

and change the.

Multiplied value down here

to make it point one of the
original intensity of the map.

Now let's plug that
into our displacement

output.

And try rendering again.

Here we are with a.

Bump map added let's see if
we can even tell a difference.

We can certainly
see a shift but.

You

can't really distinguish the
extra detail due to the noise

but you know this'll
be really good when i.

Render my final.

High sample high resolute ocean

image

but

for demonstration purposes i'm
really just showing you how i go about.

Dialing in these values

and now that i have
the bump dialed in i can

reconnect my.

Color texture to the
subsurface scattering node.

And then lastly if i
want to be thorough i can

duplicate my image texture
node and again shift control d.

And this will become
my specular map.

Keep in mind all of these maps i showed you
how to create in the realistic heads series

so

if you went through that you should
already have a detailed head model

with detailed textures like this to accompany
it that you can just plug directly into

cycles to get.

That updated.

Subsurface sea goodness

like we're doing here

i don't want you to think i'm just breezing
through these textures and happen to have

all of them

you know it's a fairly involved process
that you can see in the realistic heads

series but

anyway.

The last map I'll show
you is the spec map.

And if we plug this into.

An emission no to see exactly
what we're dealing with.

You can see that it's
based on the color map with

that's been

converted to a black
and white value map

and that we have some highlighted
areas of white around the eyelids to.

Give us more of a a

wet

eyelid kind of look also in the.

Lip ps we want those to be a little
bit more reflective due to their wetness

but then in general
we just have a breakup.

Of the skin

speculating.

So we're going to
plug this into a

let's see color mix rgb node.

And use the image as the factor

and then from there we will I'll
choose colors that we want to be

are low value and are high value

for this top color
swatch which will be.

The lowest value of speculating.

Let's make that.

Point three.

And then take it
towards the blue direction

a little bit.

I like that.

Because when it comes to human skin it
helps to take the specular reflections into

the blue spectrum
just a little bit.

Let's

copy that color swatch now

with hovering over it and hit and control
c then pacing it with control v over the

next color swatch

and let's take that value from
point three all the way up to one.

And now we have that variation.

In the specular map but we have a little
bit more control over it and we don't want

the lower value to be zero we
still want it to reflect a little bit

but and.

I tend to make my my controlling maps be
black and white because that's easier for me

to understand.

It maps

and also i'd see how easy it is to plug
it into a mix note and dial in specific

values after the fact like here

in the shading network but
anyway now that i have that setup

let's plug that into
our glossy color.

And

that should help to break up.

Our glossy component
of the sky when.

A very realistically because.

Before this it was very
uniform across the entire.

Head

and breaking that up
certainly will help with realism

so at this point i think
i'm happy with my shader

based on the preview
down here and i will.

Let's increase my samples
for for a final render from

five hundred to one thousand

and hopefully be done
with this simplistic.

Skin shader.

And at about six
and a half minutes.

Which really isn't too bad.

Considering you know we're at a fairly high
resolution and certainly a lot of samples.

And.

It's a pretty good.

Representation of skin i think but like
everything it could of course use some more

tweaking

but at this point i'm
fairly satisfied fide

and

i would begin to do test renders in different
lighting conditions one thing that i

notice can affect
a skin material.

More than

you might expect is
the environment light.

So

let's switch to
slot number three

and.

Enable.

My world environment texture which is
key currently at a strength of zero so it's

basically turned off.

What if we switch
set to number one

and it's.

Clearly way too strong
so it's good to point five.

And this represents
more of a daytime.

Rendering scenario

and while this looks
pretty good and typically.

In environment lights
once they are introduced.

I'll have to go back and re address my
subsurface settings because it needs to look

good in both lighting conditions

but i suppose at this point i'm pretty
satisfied with the simplistic version of the.

Skin shader

and i know i'm calling it simplistic
but if we take a look at the node editor

so some might not call this simplistic
because we have a lot of nodes in here

but that's mainly due to
the textures that i'm using.

Because as far as sub-surface
goes it's just one node.

One layer if you will.

It's very common when it comes to skin
shaders to have a tri layer system which i

went over with blender internal

in the realistic head series

and if you come from mental ray or v
ray or other high end render engines.

You'll be familiar
with the tri layer system

that's where it can
get really complex and

in blender again
Matthew heimlich has

ported Arnold's

complex shader.

Into blender as a node group and that's
what i'm going to show you next but.

If you feel satisfied with the result that
i'm kind of showing you and feel satisfied

with the

range of options
that you have to tweak

just the subsurface
scattering node by itself

then this is.

A good option for you
it's what i tend to do.

Namely because i'm satisfied with the
rest salt and this next method the complex.

Arnold port shader

takes almost twice the amount
of time to render and clean up

but it does give you all those options
that you're used to if you come from one of

those commercial render engines.

So that is what the
next lesson is about.