Making shape keys

After reading this page you will be able to sculpt a new shape key, extend it left and right with a mirror key, organize the list with groups and locks, and check that the key was made correctly.

Assumptions: a SkinnedMeshRenderer is loaded, and you are on the Shape Keys tab.

Sequence

1. Set the base state
2. Sculpt one side
3. Make the other side with a mirror key
4. Organize with groups and locks
5. Check
6. Save

1. Set the base state

A new key starts from the absolute shape you see on screen now. If other keys are on, you sculpt on top of that shape.

Press Reset All to 0 to bring every key down to 0 before you start. Leave keys on only when you want to build a key on top of a specific expression.

2. Sculpt one side

Press the new-key button, or press N in the Scene view.

When a bar shows that a key is being sculpted, the sculpting has started.

• Drag: grab
• Shift: Smooth
• F: radius, Shift+F: strength

Enter a name in the Shape key name field that shows left and right clearly. The mirror step in the next section flips this name.

Example name	Mirror result
eye_close_L	eye_close_R
L_brow_up	R_brow_up
smileLeft	smileRight
cheek_puff	cheek_puff_Mirror

Press Enter to confirm the new key, or Esc to cancel if you are not happy with it.

Confirming does not change the asset yet

Confirming here is a session confirmation. The mesh asset is updated only when you press Save Mesh. → Shape Keys

If you are not happy with the sculpt, you can edit it again. Press the edit button on the key's row to load its 100% shape, and continue sculpting. You can also move to Shape or Select & Move while you work (multi-tab editing), then come back and finish with Save. You cannot save an edit that changes the vertex count (delete or separate).

3. Make the other side with a mirror key

Press M on the row of the key you just made. The mirror axis is usually X.

The left and right topology does not have to match exactly. The tool finds pairs by spatial matching. A vertex with no partner is mirrored only if it lies on the symmetry plane.

If the mirror key is not created, the tool could not find a symmetric partner. If the mesh is asymmetric from the start, you must sculpt the opposite side by hand.

4. Organize with groups and locks

When you have more than about twenty keys, the list gets long.

• Turn on Group to fold the list by name prefix. If you decide on prefixes such as eye_, mouth_, or brow_, the list is easier to manage.
• Lock a finished key with L on its row. Locked keys are left out of bulk value changes, deletion, and key import from another mesh.

You can also select several keys with Ctrl or Shift + click, and lock them all at once.

To reorder, select the keys and press ^ / v. Moving several keys is also one undo step.

5. Check

Check that the key moves only where you intended.

1. Press S on the row to turn on the solo preview. Only that key is shown at 100.
2. Turn on Heatmap and click the key. The vertices that actually move are shown in color.
3. If a wrong area is colored, the brush radius was probably too wide when you sculpted. Go back to editing and refine it.
4. Press Esc to clear solo.

Turn on Extended range to push the slider to -100 to 200. Use it to check that the shape does not collapse when exaggerated. Do not save at those extreme values.

6. Save

There are two choices.

• Save Mesh: bakes the whole mesh, including the key structure, to <source name>_Edit.asset, and ends the session.
• Save as New Key: stores only the change you added to the base shape as a new key, and continues the session.

When you are making keys, Save Mesh is usually the one to press. Save as New Key is for when you changed the shape with Shape, want to keep the base mesh as it is, and want to keep only this change as a key. → Quick capture and Save Mesh

Restoring an existing expression

After you change the base shape, you may need the original face again. The Reverse button on that key's row creates a reversed key (_Revert).

To lock the current look into one key, use Merge applied values. The results of all keys that are not 0 become one new key at 100, and the source keys return to 0.