Blender | Rigging Practice Part 3: Arm

This is a continuation of the tail rigging from last time.
This time it’s the arm.

Rigging

1｜Setting Up the Bones

2｜Create the Controller Bones

First, create the control bone for the arm.
Duplicate the end bone of the arm with shift + d, then right-click to confirm.
Since the identical-sized bone overlaps and is hard to distinguish, increase the Length value in the properties panel on the upper right.
Then do the following.

• Disable Deform in the Bone properties.
• Clear the parent relationship with alt + p.
• Set the IK bone’s name to IK.Arm.

▼ Here’s how it looks so far ▼

Next, create a control bone for the Pole from the elbow.
Switch to a top-down view and create the Pole bone from the elbow with shift + e.
Then use g + y to move it away from the elbow.

Then do the following.

• Disable Deform in the Bone properties.
• Clear the parent relationship with alt + p.
• Set the Pole bone’s name to POLE.Arm.

Next, switch to Pose Mode.
Select the tip bone of the arm (not the IK bone) and add IK from Bone Constraints.

Set the target to the armature and the bone to the IK bone.
Set up the Pole in the same way.
Since the number of bones to link, including itself, is 3, change the value from 0 to 3.
Setting the Pole shifts the local rotation vector, so correct it.
※ It’s usually off by roughly 45 degrees.

3｜Check the Movement

If you actually move the IK bone around with g, you can confirm that the arm moves in sync.

You can also confirm that moving the Pole bone around with g rotates the elbow.

※ In the gif, the IK bone has been offset slightly to make the movement easier to see.

This completes the arm rigging.