Control Bones  &
Inverse Kinematics 

Control Bones & Inverse Kinematics (IK)

INVERSE KINEMATICS:

1. Extrude from tip of bone to add a new bone (will become our "Control" or "IK" bone)

   1. Test - what does this do?!

2. In "Edit" mode: "Clear" parent [Alt][P]

3. Select new (or extruded) bone AND hold down [Shift] key and also select previous bone (or last bone in the chain)

4. In "Pose" mode: Add IK to Active Bone [Shift][I]

5. This will now impact your entire bone chain.  You may have to set number of bones to affect:

   1. Select last bone (not your control bone!)

   2. Go to "Bone Constraints" tab on right side menu (Under "Bone" tab)

   3. You should have an "IK" constraint from step 3.

   4. Adjust your chain length to the number of bones you want to impact

6. Last step: add directional constraints. Why? So the movement behaves as you expect.

   1. Select the first bone in the chain (furthest from control bone)

   2. Go to "Bone Properties" tab (right side)

   3. Go to "Inverse Kinematics"

   4. Click the lock on "Lock IK X" (or "Y" or "Z")

   5. Can set for multiple bones:

      1. Hold [Shift] and click on multiple bones

      2. Hold down [Alt] and select IK lock for X, Y, or Z.

   6. For  spider leg like motion:

      1. Lock "Z" for bones.

CONTROLLERS:

1. Parent IK to ANY object! (can be a custom shape)

   1. You can animate in "OBJECT" mode! SO easy!

   2. You will want to turn on "Auto Keyframing"

   3. Steps:

      1. in Object mode, add a shape/object/custom object

      2. In pose mode, select the IK and go to IK modifiers

      3. Add a "Child of" modifier

      4. Select the shape you just make

      5. Go to Object mode and voila!

2. Under "Object Data Properties (for armature)

   1. under "Viewport Display"

      1. select "InFront"

      2. select "Axes"

BODY EMPTY:

1. Parenting your main body rig to an “empty” can simplify moving your object.

2. Add an empty (Object mode) and move it above your body

3. In Object mode, select the entire rig, hold down “Shift” and click on the Empty

4. [Ctrl][P]

   1. Select “Object Keep Transform”

REVIEW: Parenting Bones to objects

1. Select the mesh

2. [Shift] select the  armature (will select ALL bones -  probably not what you want - SO:)

3. [Ctrl][Tab] and then select the bone you want

4. [Ctrl][P] to parent to bone

5. [Ctrl][Tab] again to exit Pose mode
   
   

BONUS 1: You might want or need your IK bone to have an "offset" from your other bones so that you can easily find it.

1. On right side, go to the Bone Properties tab

2. Under "Custom Object" set your "Translation" values in X, Y, and Z.

BONUS 2: How do you easily find your control bones? Use a different shape!

6. 6. 2. On right side of interface, find "Scene Collection"

      3. Below the last element, Right click and select, "New Collection"

      4. You can hit "/" to isolate

      5. Add a new object of your choice (for example a Torus)

      6. You might want to thin it [Alt][S]

      7. Hit the camera button to hide it from rendering (Scene Collection window)

      8. hit the "/" again to go back to your main 3D window

      9. Select your control bone

      10. Click the "Bone" tab (right side)

      11. Find "Viewport Display"

      12. Under "Custom Shape" select your shape from "Custom Object"

      13. Want to change the size or rotation of control bones?

      14. switch to "Object" mode

      15. Make changes

      16. [Ctrl][A]

          1. select: rotation + scale