Troubleshooting spine twist controls

00:03

Now we need to get the upper spine to twist with the shoulder control.

00:08

The problem is the twist attribute is now locked. So we can't edit it.

00:14

If we connect the shoulder controls, rotate Y attribute to it,

00:17

it will break how the lower spine works.

00:20

So what we need to do is add the shoulder controls, wire, rotation into the mix.

00:26

So we can do this with another node here.

00:29

Add the shoulder control to the node, editor,

00:33

remove this

00:35

and open neck.

00:38

So

00:39

press tab and create a plus minus average node,

00:44

rename it to shoulder twist PM.

00:48

This node will take a series of values and add them together for us,

00:52

subtract them or find the average.

00:56

OK. Let me get organized.

00:58

First, we need the current twist value. So the one which is being taken away,

01:03

this is coming from the multiply divide node.

01:07

So connect output X to input one D zero on the plus minus average node,

01:14

we now want to add the shoulder rotation to this.

01:17

So take its rotate Y attribute and connect it to input one D one.

01:24

So with those now added together,

01:26

we can connect the output one D from the plus minus average node

01:31

to the twist attribute.

01:33

OK. Let's try this. Now

01:36

the hips still work good.

01:38

The shoulders now twist too perfect.

01:41

OK. So we have another problem.

01:43

The chest control,

01:46

we need that to also twist the upper body too.

01:50

Well. Now we have this network set up, we can easily add another control to it,

01:55

bring the chest control into the node editor.

01:58

And all we need to do is add that to the plus minus average node two.

02:03

So it's taking into account its rotations too.

02:07

So connect, rotate wi to input one D two.

02:12

There we go.

02:13

That works now and influences the upper torso.

02:19

Let's test down here.

02:23

So it looks like we have a similar issue down here.

02:27

The lower spine control isn't twisting the spine.

02:31

Now you may want it set up like this, which is fine.

02:34

But I think we might add the functionality back in

02:38

the good news is we can use the same setup as we did with

02:41

the chest control and simply add the hip and lower spine rotations together.

02:46

Let's move the hip control up here.

02:49

So we can add another plus minus average node here.

02:53

So let's create a new one.

02:56

We can just duplicate this one, actually

02:58

open it up

02:60

and rename it to hip twist P MA

03:04

connect to the hip controls, rotate Y attribute to input one D zero.

03:10

Let's remove some of these

03:12

and bring the lower spine control in

03:15

ah OK.

03:17

Looks like I accidentally called this root twist multi.

03:21

When I was reorganizing the scene,

03:23

it should actually be the hip twist P ma node.

03:26

Sorry about that.

03:28

I'll make sure it's corrected in the source files.

03:31

So just make sure you're connecting to the hip twist P MA node,

03:35

not the root twist multi

03:37

node.

03:39

So now connect the lower spines rotate Y attribute to the

03:43

input one D one attribute on the plus minus average node.

03:48

Now connect output one D to the raw attribute on the IK handle.

03:54

We can now use that to control the lower torso

03:59

and the hips still work too.

04:01

Upper spine works great.