Wiring the FK controls

00:03

So now the spine, head and neck are rigged. So let's turn our attention to the limbs

00:09

first. We're going to wire up the FK controls.

00:12

And these are very similar to how we built the FK spine.

00:17

Let's hide the leg controls for now and focus on the arms.

00:21

All we need at this stage is for the FK controls to move and rotate the FK joints.

00:28

As we are focusing on FK, we can hide the IK controls for now.

00:33

And these poor vector controls,

00:36

I'll just find the armed group in the outliner.

00:40

So the root control moves the whole arm

00:43

but the FK controls don't currently follow it.

00:46

So we need to make a few changes to how this works.

00:50

Let's hide the I care joints first

00:54

and move the arm IK and FK joints out of the arm group

00:59

and also delete that group.

01:02

I realize this will break things for now,

01:04

but we need to rework the hierarchy. So the FK controls work with the rig.

01:09

Next, we need to clean the translations from the joints.

01:14

So just as we have done many times before, move the values from here

01:19

down here

01:20

or use the script provided to speed things up.

01:23

That's the ICA joint done.

01:25

Now, the FK,

01:27

so you see the FK arm has rotated to here,

01:31

this is because we have joint orient values down here,

01:35

which had now been applied on top of the offset parent matrix values.

01:40

So we just need to remember when working with joints, we need to remove those two.

01:45

I'll do the same on the IK joint too.

01:48

We now need to repeat this for the rest of the FK joints.

01:52

So we can connect the controls like we did with the spine.

01:56

So copy the translate Y here

01:59

down to here.

02:01

This now doubles the distance this joint is from its parent.

02:06

So we just need to zero out the main attribute to move it back

02:10

and now do the same with the hand FK joint

02:14

reset this to move it back.

02:17

So now we can set this arm up in exactly the same way that we did the spine

02:21

using direct connections,

02:24

which is why we needed the joints translations to be zeroed out,

02:29

open the node editor

02:31

and bring the FK controls in

02:34

just reorganize these.

02:36

And now bring the FK joint in too.

02:40

I'll move these so they are next to the same controls.

02:45

Now connect the hand controls, rotate attribute to the hand FK joints,

02:50

rotate attribute

02:52

and also connect the translations

02:55

repeat this for the lower arm,

02:57

connecting the rotations and translations to the lower arm FK joint.

03:03

We need to do something different for the upper arm.

03:06

If you remember,

03:07

we had to connect the spine differently too.

03:10

So it would inherit any parent translations

03:13

this time, connect world matrix zero

03:17

to offset parent matrix.

03:20

We can move the route now and the FK arm controls follow.

03:25

If we use direct connections,

03:27

it would stay in world space and we saw this with the spine.

03:31

So now we can control the arm using forward kinematics.

03:36

Nice and easy.

03:37

And we didn't need to use any offset groups or constraints.

03:41

While we are here, we also need to check the rotate orders.

03:45

You see the joint is set to YXZ

03:49

and the control is XYZ.

03:51

We ideally need these to match.

03:54

So let's update the control.

03:56

I don't know if you did, but did you notice that the arm moved slightly as I changed?

04:00

It,

04:01

it was only a little movement but this is

04:03

why it's important to update the rotate orders.

04:06

So the controls and joints are synchronized.

04:09

If you do this later, once the character has been animated,

04:12

the animation would change and need to be redone.

04:16

Let's update the other controls.

04:19

OK. That's the arm done.