All language subtitles for CustomMetahuman_8.1.mp4

We are now finally at the point,

where we can rig our outfit
to the Metahuman character.

All the hard work of designing
and modeling the clothes,

retopology, UV unwrapping and texturing is done.

This is the final step of the clothes
creation pipeline

before we can bring everything
into Unreal Engine,

and see how our Hero looks like
with clothes on.

So what is rigging?

Rigging is the process

of creating a skeleton and then parenting
the mesh to this skeleton.

The parenting or binding of the mesh
to the bones of the rig is done via vertex groups and weights.

Let's have a quick
look at this simple example.

We have a mesh called Body.

It has no vertex groups assigned,
and is not parented to anything yet.

Then we have a skeleton consisting of seven bones.

I named the bones
Pelvis, Spine1 and 2, Neck and Head.

All these bones are in a straight hierarchy.

And then we have two bones for the arms,

which are both parented to the Spine1 bone.

Let's parent the body to the skeleton, select
the body, then the rig and press CTRL+P.

You have a couple of options for
how you want to bind the mesh to the rig.

Let's choose "With automatic weights" first.

What Bender does is,

it first creates vertex groups
for the body mesh.

There is now a vertex group
for each bone of the skeleton.

You can see which vertices belong
to which group in edit mode.

The groups are not exclusive,

that is, a vertex can simultaneously
belong to several groups,

or in other words,

the vertex can be simultaneously influenced
by several bones of the skeleton.

Now, because we chose automatic weights,
Blender did not only create vertex groups,

but also automatically assigned
a weight to each vertex

based on the proximity of this vertex
to the bones of the skeleton.

If you select a single vertex,
you can see the weights

that have been assigned to it
here in the N-panel.

For example, this vertex is mostly
influenced by the Pelvis bone, but

will also move slightly if the Spine1
or the left arm bones are moving.

This vertex will retain its relative
position for all bones and will only move

when the left arm bone is moving.

You can also visualize this weight information
if you go into weight paint mode.

Selecting a vertex group will show you,

how different parts of the mesh
will be influenced

by the respective bones of the skeleton,
with red being high influence

and blue no influence at all.

If you select the skeleton and then
the mesh and then go into weight paint mode,

you can also just click through the
different bones with CTRL+left-click.

Also, the skeleton is now in Pose mode,
which means you can rotate each bone

and directly check
how the mesh is behaving.

The automatic weights operation
will produce different results

if the vertices of two meshes
are not in exactly the same position.

We have, for example,
a second mesh here called Clothes.

This one has a slightly different topology.

Now, if I parent it to the rig
with automatic weights,

and then move the bones,
we run into severe clipping issues,

because the character body
and the outfit mesh

have a quite different vertex weights distribution.

So using automatic weights for clothes
is not the best option.

But, what we can do instead is parent
the clothes to the rig "With empty groups".

This means Blender will still create
the necessary vertex groups,

but the vertices
will all have a weight of zero.

Moving the bones will not influence anything.

And now we want to transfer the weight distribution
from the body mesh to the clothes mesh.

It's much like baking information
from a high poly to a low poly mesh.

for each vertex of the target mesh
(which is our Clothes),

Blender will look for the nearest vertex
on the source mesh (which is the Body),

and copy the vertex weights from it.

The modifier for this operation is called
"Data Transfer".

Let's select the source, check
Vertex data and select Vertex groups.

Now we can apply the modifier.

If we check now how the clothes move with the rig,

the result is a lot better.

No more bad clipping!

All right, let's rig our real clothes now.

The "Avatar" has now served its purpose,
and we can hide it.

Instead, we will use the "Rig" character.

Because the clothes will be using
the metahuman body skeleton,

we can ignore the face rig.

Select the clothes and the body skeleton
and parent them with empty groups.

So our clothes now have all the vertex
groups for the body skeleton.

Lets drop the Data Transfer modifier on the clothes,
and then join body and head of the character with CTRL+J.

Now, in the data transfer modifier,
we can select the joined character mesh as the source.

activate the Vertex Data,

select Vertex Group,
and then click on "Generate data layers".

This will create additional vertex groups
for the head as well.

When we parented the outfit to the body,

blender only created vertex groups
based on the bones from the body skeleton.

Since we need vertex groups
for the neck and head as well,

Clicking on "Generate data layers" will do exactly that.

Now we can apply the modifier
and check our vertex weights.

Beautiful!

We managed to rig the clothes
to the metahuman skeleton.

Although we come really close
to an animation-ready outfit,

by transferring the weights
from the body,

the result is far from perfect.

We have sharp gradients for the vertex weights.

Parts of the mesh are attached to bones
that should have zero influence,

and we have ugly stretching issues
in the crotch and armpit areas.

So this will require some adjustments.

In the next chapter,
we will look into skinning or weight painting,

and fix those issues.