Updating the second twist joint

00:03

Now we need to update the second twist joint here.

00:07

We want this to be rotated halfway between the upper arm joint and the elbow.

00:13

So we get a more gradual blend

00:15

open the node editor

00:18

bring in the main upper arm joint, not the twist joint

00:23

and now bring in the second twist joint

00:27

open these up.

00:31

So we want to affect the rotate Y axis.

00:35

If we connect the rotate wire attribute on the upper arm

00:38

directly to the rotate wire attribute on the twist joint,

00:43

we are getting the rotation back but it's far too much.

00:46

So we need a way to reduce that value.

00:49

Let's create a multiply divide node

00:52

and call this arm twist multi.

00:55

Although you should add the left in here too.

00:58

So it won't clash when you do the right arm,

01:01

connect the upper arms Y rotation to input on X

01:06

and then output X to the twist joints, rotate Y attribute.

01:11

So as we have seen before, we can use this to adjust the main rotation value

01:17

at the moment. Input one X is being multiplied by input two X. So by one,

01:23

which means we will get the same value

01:26

if we change input two X to 0.5

01:29

we will be getting half the value.

01:32

So if we rotate the control, now

01:35

the twist joint is moving half the amount

01:38

giving us that nicer more gradual blend down the arm,

01:42

we can rotate the upper arm now

01:44

and the shoulder stays level.

01:46

And the bicep area is following

01:50

one quick tip would be to create a custom bicep twist attribute

01:54

and connect that to the input two X attribute on the multiply divide node.

01:60

This will then give the animator complete control over how this area twists.

02:04

So they can correct it if they need to on more extreme poses.

02:10

OK. Let's reset this.

02:12

All we need to do now is make the follow joint move with the torso.

02:16

Otherwise the locator will be left behind

02:19

and then the shoulder won't deform as expected.

02:23

Let's move the torso.

02:25

OK. So we probably want to follow the spine three joint here. This is the closest

02:31

we aren't going to parent the follower joints to

02:33

it as that would change the main skeletal structure

02:36

and they would ultimately end up being exported to the engine.

02:41

So let's just constrain them

02:42

and we can just use a parent constraint with maintain offset enabled.

02:50

OK. Good that now follows.

02:55

Now move the follower joints to the main arm group under the rig systems group.

03:01

So we've done the upper arm and the shoulder now deforms in a more natural way.