All language subtitles for CustomMetahuman_2.1.mp4

Before going into texturing, clothes,
and other things we want to add

to our character,

it is important to first
adjust our geometry,

since the textures and clothes will
then follow the form of the head and body.

Maybe we want to transform
the clean human form into an elf

or some alien looking creature.

So working on the mesh
would be the first step

in our customization process.

As pointed out in the previous chapter,
we need a workflow that doesn't break

any of the functionalities
of the metahuman.

There probably are a number
of different ways to approach this.

What I will show you here is a workflow
that allows you to modify the mesh

using Blender and an Unreal Engine
plugin called Mesh Morpher.

This plugin is unfortunately quite pricey,

but in my opinion it is worth the money.

You can find it on the Unreal Marketplace,
just search for Mesh Morpher.

And it is also available on Artstation.

You can find the link in the course description on Gumroad.

They also have a ton of tutorials
and how to use it.

So if you have any questions beyond
what I'm showing here,

feel free to dig in and get familiar
with its functionalities.

Right...

So after you install it to the engine,
you need to activate it

in the plugin settings of your Unreal Engine project.

And after activating the plugin,
you will have to restart the engine.

Now you can access it

via this icon on the top bar.

Now, let me quickly

explain what this plugin actually does.

The way it works is as follows:

The plugin uses two OBJ files

to create a morph target
for the skeletal mesh.

One is the original mesh,

let's call it the Morph Base.

And the second one is the Morph Target.

This is what you create in Blender
by using the sculpt or editing tools.

So we need to take our metahuman
base character in Unreal Engine,

create an OBJ file for the head and the body,

modify them in Blender to our liking,

and then use Mesh Morpher to generate
a new metahuman character,

with those modifications applied.

There is one major caveat for morph
targets though. You cannot perform

any operation on the mesh
that changes the vertex count or order.

Let me explain:

You know that any 3D geometry

is made up of interconnected vertices
or points in 3D space right?

Now, what you are typically never concerned with,

when you are creating your 3D
objects, is the vertex order.

This all happens under the hood,
and in most cases

the vertex indices are of absolutely
no relevance to you.

But in this case, it actually is.

Let's look at the body
mesh of our Hero model for example.

If you go to the preferences,
you can activate the developer tools

in the interface tab.

When you then go into edit mode,

there is an additional option in
the overlays dropdown menu called "Indices".

This will display the actual index

or order number
for any selected vertex on your mesh.

So every single vertex has a unique number
assigned to it.

What Mesh Morpher does is,

it compares the original mesh (our Morph Base)

and the changed mesh
(our Morph Target),

and looks whether a vertex has changed its location
in 3D space.

For this comparison,
all vertex indices of the two meshes

need to be the same.

So where's the problem?

There are a lot of operations
in a typical modeling

or sculpting workflow that actually affect
and change the indices,

by merging, deleting, or adding vertices.

So you cannot use the Merge By Distance function

to join body and head, for example.
You cannot cut or subdivide the mesh

and you cannot apply
Multiresolution or Subdivision modifiers.

All these operations will change either
the vertex count or the vertex order.

And since Mesh Morpher

needs two meshes with an identical
vertex count and order,

the only thing we are allowed to do
is move vertices around.

Actually, it's much like the shape keys
function in Blender.

If you try to apply a subdivision
modifier, for example,

Blender will tell you that
you can't do it to a mesh with shape keys.

Although the blend shapes in Blender
are a bit more forgiving,

so if you do change the mesh
in a destructive way,

the blend shapes still kind of work,

the Mesh Morpher plugin will not work well+

with this type of modifications.

So if you see something like that,

then that's the reason why.

In sculpt mode,

you can use any sculpt tool you like,

but you are not allowed to use Dyntopo or Remesh,

since those modifications will absolutely
change your vertex count and order.

All right.

Now, with this out of the way, let's

go and export our character.

Open up the Mesh Morpher plug in,

and select your body mesh.

We will then export this mesh
as an "OBJ watertight".

I will call it Hero_Body_UE.

Do the same with the face mesh.

I call this one Hero_Head_UE.

I call this one Hero_Head_UE.

You probably ask yourself,

why did I choose the watertight OBJ
for export and not the regular OBJ.

If you select the second option called "OBJ watertight",

this will give you a welded mesh.

A welded mesh means that all
overlapping vertices will be joined.

Let me quickly show you the difference
between the two options.

I have here two OBJs.

The right one was exported
using the first option:

Export as OBJ.

The one on the left was exported
using the OBJ watertight option.

If I now go into

edit mode and press
L to select linked mesh parts,

you see that this one
consists of different separated parts.

The watertight version,
however, is one single linked mesh,

which is better
when we start sculpting on it.

Now we will import those OBJ files in Blender.

For the import options, we need to set
the transform to -X forward and Y up.

This is just how the
Mesh Morpher plugin is set up.

By the way, you can save import and export

options in Blender as a preset.

So when you restart Blender,
you can choose the preset

and everything will be just set up
correctly.

Do the same for the head.

Here we want to deselect "split by object"
in the Geometry section.

Otherwise you will get separated
mesh parts for the eyes, teeth, etc.

For sculpting, we want it all to be one mesh

Let's keep things organized and rename those,

so we know what meshes serve which purpose,

and move them into a new collection

by pressing M,
with both objects selected.

Then let's duplicate the meshes
and move them into another collection.

This duplicate will be the mesh that
we will modify and use as our Morph Target.

We are now ready to actually begin working.

Now, at this point, I would recommend that
you pause watching the course,

and begin working on your character on your own,

Since your model will probably
look much different than mine,

feel free to get your creative juices
flowing and make something of your own.

In the next video, I will show you
the modifications I did to my Hero character

using anatomy references
and basic sculpting operations.

But this is optional.

Also, if you encounter problems
around the head-body border, don't worry.

That's normal, and we will fix it later.