user: Show practical ways to work with Shape Keys Panel in a Blender add-on or script – include code.

assistant: # Shape Keys Panel

[image reference removed]

Shape Keys panel.

The *Shape Keys* panel is used to create, organize, and manage shape keys.
It presents a tree view where shape keys can be reordered by click-dragging.

Shape Key element

> Value/Frame (number)
> :   In Relative mode: Value is the current influence of the shape key used for blending between
>     the shape (value=1.0) and its reference key (value=0.0). The reference key is usually the Basis shape.
>     The weight of the blend can be extrapolated above 1.0 and below 0.0.
>
>     In Absolute mode: Value is the *Evaluation Time* at which the shape will have maximum influence.
>
> / Mute
> :   If unchecked, the shape key will not be taken into consideration when
>     mixing the shape key stack into the result visible in the 3D Viewport.
>
> / Lock Shape
> :   Shape keys can be locked to protect them from accidental modification due to inadvertently
>     selecting the wrong key for editing in the list. Most common sculpt and edit mode operators
>     and tools that move vertices abort with an error if the active shape key is locked.

Shape Key Specials
:   > New Combined
    > :   Add a new shape key with the current deformed shape of the object.
    >     This differs from the  button of the list, as that one always copies
    >     the Basis shape independently of the current mix.
    >
    > Duplicate
    > :   Creates a copy of the active shape key.
    >
    > New from Objects
    > :   Add the vertex positions of selected objects as new shape keys,
    >     or update existing shape keys with matching names.
    >
    >     To use, select the object(s) to copy shape data *from*,
    >     then the target object to copy shape data *to*, and perform the operation.
    >
    > New from Objects Flipped
    > :   Creates new shape keys from selected objects while mirroring the vertex positions
    >     across the local X axis. This is typically used when creating symmetrical shape keys
    >     (for example, generating a *Left Smile* from a *Right Smile* shape).
    >
    >     The operation requires the topology of all involved meshes to match.
    >
    > Update from Objects
    > :   Updates existing shape keys of the active object with the vertex positions of
    >     selected objects that have shape keys with matching names.
    >
    >     To use, select the object(s) to update shape data *from*, then the target object to
    >     update *into*, and perform the operation.
    >
    > Update from Objects Flipped
    > :   Similar to *Update from Objects*, but applies a mirrored update across the local X axis.
    >     This is useful for updating symmetrical shape keys when working with mirrored geometry
    >     or pose-corrective shapes.
    >
    > Flip
    > :   If your mesh is symmetrical, in *Object Mode*, you can mirror the shape keys on the X axis.
    >
    >     This will not work unless the mesh vertices are perfectly symmetrical.
    >     Use the Mesh ‣ Symmetrize tool in *Edit Mode*.
    >
    > Flip (Topology)
    > :   Same as *Mirror Shape Key* though it detects the mirrored vertices based on the topology of the mesh.
    >     The mesh vertices do not have to be perfectly symmetrical for this action to work.

    > Make Basis
    > :   Makes the selected shape key the new *Basis* shape key. The vertex positions of the
    >     active shape key are applied to the base mesh, and all other shape keys are adjusted
    >     relative to this new basis.
    >
    >     This operation is useful when a corrective or edited shape key should become the
    >     default shape of the mesh instead of the original basis.
    >
    > Apply All
    > :   Saves the current visible shape to the mesh data and deletes all Shape Keys.
    >
    > Delete All
    > :   Removes all Shape Keys and any effect that they had on the mesh.

Relative
:   Set the shape keys to *Relative* or *Absolute*.
    See [Relative or Absolute Shape Keys](introduction.xhtml#animation-shapekeys-relative-vs-absolute).

Shape Key Lock (pin icon)
:   Show the active shape in the 3D Viewport without blending.
    *Shape Key Lock* gets automatically enabled while the object is in *Edit Mode*.

Shape Key Edit Mode (edit mode icon)
:   If enabled, when entering *Edit Mode* the active shape key will **not** take maximum influence as is default.
    Instead, the current blend of shape keys will be visible and can be edited from that state.

Add Rest Position
:   Creates an [Attribute](../../modeling/geometry_nodes/attributes_reference.xhtml) in the vertex domain called
    `rest_position` which is a copy of the `position` attribute before shape keys and modifiers are evaluated.
    Only mesh objects support this option.