All language subtitles for CustomMetahuman_4.1.mp4

Let's make some hair!

With the groom system in Unreal Engine,

With the groom system in Unreal Engine,

we don't have to go through

the complicated process
of creating hair cards for our characters.

Instead, we can create hair
particle systems in Blender and import them

as Alembic files into Unreal Engine
with really beautiful results.

So in this chapter,

we will have a look at the workflow
of creating custom hair for our Hero.

I will show you two ways of creating hair:

One is the native blender hair particle system,

and the other one is a free
blender addon called HairNet,

which is quite useful
to make specific hair types.

Creating hair is always a process that requires

a lot of tweaking and finetuning
to achieve a good looking result.

So depending on the hairstyle you are going for,
this chapter

might not give you a step by step instruction
for every use case,

but I hope you learn the fundamentals
of the hair system in Blender to get

you started for your own projects.

Right...

Let's get to it.

First, let's download
and install the HairNet addon.

You can find it on GitHub at this address.

Click on the releases
and download the latest version.

Then open up the preferences in Blender
and install the addon.

I'm using Blender 2.93, by the way.

After installation,

you can find it in the N-panel
under the tab called Hair.

The feature that I want to use for my hair
is the Add Hair From Sheets feature.

Let me show you how it works.

All it needs is a mesh with some edge
loops and seams.

What it does is creating hair strands
along the normal edge loops

with hair subdivisions at every seam.

Let's create a plane, make some loop
cuts, and mark them as seams.

Then we need to make sure Emit Hair on Self
is checked and click on Add Hair From Sheets.

Then we need to make sure Emit Hair on Self
is checked and click on Add Hair From Sheets.

The tool generates two hair strands
along the two edges of the plane.

We can hide the plane itself
by unchecking the Show Emmitter box

in the Viewport Display section
of the particle details panel.

After the hair is generated,
you can treat it

like any hair particle system.

So if, for example,

you go into particle edit mode,
you can groom the hair to your liking.

And the nice thing is
it is non-destructible.

So if you decide to change the shape
of your emitter plane,

you can regenerate the hair particles
and they will adjust to the new form

of the emitter geometry.

Also, maybe you want to increase the hair
density and introduce

additional loop cuts.

You can do that. Just delete
the particle system and generate it again

after you have made changes
to the emitter plane.

So now that we know how to use
the HairNet addon,

let's go ahead and actually make some hair
for our character.

I want to make the King Harald hairstyle
from the Vikings TV show.

So I will start with the top hair first
and then create

additional particle systems
for the shorter hair and hair layers.

We of course could just use
the Blender hair tool

to create this,
but I find that working with the HairNet tool

gives me more flexibility
to duplicate hair strands, move them around,

and adjust individual parts of the groom.

Let's begin then.

I used the OBJ file

of the head that I exported
from Mesh Morpher in the second chapter

of this course, as my character head.

I then positioned the cursor on the head
with Shift-Rightclick

and create a plane.

I select two vertices and extrude
a couple of times

to create the emitter plane
that I want to use for the hair.

After that, it's just duplicating the mesh

a couple of times, moving it into position
and adjusting the vertices

until I get a base
that roughly matches the top hair

from the reference images.

I do the same thing to create the bun, or knot

at the back of the head.

Now that I am happy with the base,

I go through every object and adjust them.

For example, I add loop cuts for the meshes
where I want the hair to be more dense,

and mark the seams
and adjust some vertices.

Once an emitter plane is finished,
you can either hide it by pressing H

or move it into a hidden collection
by pressing M.

When that is done,
I go through all the meshes one by one,

and create hair particle systems
with the HairNet add on,

as I showed you before.

Then I hide the emitter and adjust the settings
such as the radius in the Children section

Then I hide the emitter and adjust the settings
such as the radius in the Children section

of the particles pannel.

You can always move
and adjust each emitter plane later.

So this workflow
allows for great flexibility.

Now that the top here is done,

let's create the short hair
for the rest of the head.

Of course, we want the hair to grow
only on the part of the head

where it's supposed to be.

So we need to paint the vertices
that will be emitting hair.

Go to the vertex tab and create a new vertex group.

I call it ShortHair.

Then go into weight paint mode,
set the weight

and strength to 1 and paint
the part of the head where you want hair.

If you press F, you can adjust
the radius of the brush.

With Shift-F, you can change the strength
of the brush tool.

Now we can create a new
hair particle system and assign

the ShortHair vertex
group to the density slot.

I then adjust the length of the hair,
set children to "interpolated",

and go into particle edit mode.

Make sure to set Preserve Strand Length
and

Preserve Root Positions in the tool options
as well as check Deflect Emitter.

Otherwise you will push the hair
inside the head mesh

when you begin grooming.

Use the comb tool
and the other tools to adjust

the hair direction, length, or puffiness.

Since my hero has a nasty scar
on the left temple,

there would probably be no hair
growing along the scar line.

So I go back to weight painting and paint
this area with a weight of 0.

As a final touch,

I add two other particle systems
for breakup hair

and one for some fine
loose hair to give it a more natural look.

For the first breakup hair system,
I set the number to 0,

and plant hair strands in particle
edit mode where I need them.

Then I just groom the hair
and play around

with the Children settings.

For the second breakup hair system,

I create a second vertex group
and paint the top hair part only.

Then I create the particle system as before,

but set the number of particles
quite low to about 50,

set Children to simple
and their amount to 10

And then again play around
with the settings for roughness and kink.

Same thing for the flyaway hair.

But here I set the amount
of children to only 2.

In the particle edit mode,

I groom the hair a bit
so it doesn't look so uniform.

And this is basically it.

The settings for the hair particles
will always differ depending on the scale

of your model and emitters.

So there is no right way to do that.

I really recommend to play around
with the sliders for clumping, roughness

and kink, adjust the hair diameter if necessary,

and just see what looks best.

In the next chapter,

we will go through the export
and import process, how to set up

the groom system in Unreal Engine,
and the hair shader options.