Editing a basic FK control setup

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So here we have a basic FK control setup.

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So the controls are parented to each other,

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which gives us that forward kinematics movement.

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This just means the rotations are evaluated from the shoulder down to the wrist.

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So forward kinematics

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with IK which is inverse kinematics,

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the rotations are evaluated in reverse. So from the wrist back up to the shoulder.

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So this allows you to do things in animation where you

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can plant the wrist or lock where the hands are.

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So these FK controls will eventually drive the

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control arm which will then move the base skeleton

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even though these are in the correct position and orientated. The right way,

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we still have a problem.

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Each control has values on the translation and rotation attributes,

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but we need them to be zero

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as a basic rule.

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All your controls should be set to zero when passing it on to an animator.

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This just makes for a cleaner, more user friendly rig.

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Now we could just freeze the transforms,

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this fixes the translations

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but the rotations have now reset,

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meaning the orientations have changed.

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Whereas we need them to stay the same as the joints,

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what we would traditionally do in this instance, is use an offset group.

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Let's press control NG to create an empty group

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and call it upper arm offset.

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We should add the L in too just so we can see that it's for the left side.

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And let's use the match transformations tool again to snap it to the upper arm joint.

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This will move it so it's positioned and orientated

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correctly just like we did with our control.

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There it is

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and it has all the values just like our control.

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If I now parent the control to the group,

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you will see that the values are now zero.

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This is because they have been offset to the group above it,

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they are zero because the control is in

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the same position and orientation as the group

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using this offset group has freed up the attributes for us

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which will make the animators very happy.

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All we need to do now is create two more for the other controls.

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Let's rename them

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and match their transforms to the lower arm and hand joints.

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Now let's organize a hierarchy.

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So these groups are parented to the controls above them

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and then the controls parented to them.

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So there we go all nice and clean because the

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offset values have been moved to the groups above them,

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we can now also still animate too.

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The problem is if you need to have offset groups on most of your controls,

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your rigs are going to start to get a bit blurted

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just like this.

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You can see that most of this rig is offset groups.

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Let's just filter them.

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OK? So yeah,

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there's quite a lot.

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Thankfully in May 2020 Autodesk introduced a whole suite of matrix nodes and tools

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and with them came the ability to offset

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these transforms without the need for any groups.

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So let's go back.

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OK. So here we have the controls with the values again.

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Let's look at the hand. First,

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all we need to do is look in the attribute editor

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here we have a new transform, offset parent matrix tab.

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All we need to do is copy the values above

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down here.

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So now the control has moved away

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but what we have done is add the translate Y value twice.

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All we need to do is zero it out of here

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and that moves back because the offset is now stored here instead.

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So we can use this instead of an offset group.

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Let's update the lower arm next

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and just copy these down to the transform offset parent matrix tab.

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So that's moved again. So let's zero out the main attributes to pull it back.

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There we go.

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Finally, the upper arm control

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and there we go. Nice and easy.

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All the values are nice and clean, ready to be animated

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and our rig is also much lighter without all those extra offset groups.

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OK?

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So now you have a good understanding of how

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controls can be built and applied to the rig.

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Feel free to start building your own.