user: Describe ActionConstraint(Constraint) from the Blender manual or Python API, including usage steps and snippets.

assistant: # ActionConstraint(Constraint)

base classes — [`bpy_struct`](bpy.types.bpy_struct.html#bpy.types.bpy_struct "bpy.types.bpy_struct"), [`Constraint`](bpy.types.Constraint.html#bpy.types.Constraint "bpy.types.Constraint")

*class* bpy.types.ActionConstraint(*Constraint*)
:   Map an action to the transform axes of a bone

    action
    :   The constraining action

        Type:
        :   [`Action`](bpy.types.Action.html#bpy.types.Action "bpy.types.Action")

    action_slot
    :   The slot identifies which sub-set of the Action is considered to be for this strip, and its name is used to find the right slot when assigning another Action

        Type:
        :   [`ActionSlot`](bpy.types.ActionSlot.html#bpy.types.ActionSlot "bpy.types.ActionSlot")

    action_slot_handle
    :   A number that identifies which sub-set of the Action is considered to be for this Action Constraint

        Type:
        :   int in [-inf, inf], default 0

    action_suitable_slots
    :   The list of action slots suitable for this NLA strip

        Type:
        :   [`bpy_prop_collection`](bpy.types.bpy_prop_collection.html#bpy.types.bpy_prop_collection "bpy.types.bpy_prop_collection") of [`ActionSlot`](bpy.types.ActionSlot.html#bpy.types.ActionSlot "bpy.types.ActionSlot"), (readonly)

    eval_time
    :   Interpolates between Action Start and End frames

        Type:
        :   float in [0, 1], default 0.0

    frame_end
    :   Last frame of the Action to use

        Type:
        :   int in [-1048574, 1048574], default 0

    frame_start
    :   First frame of the Action to use

        Type:
        :   int in [-1048574, 1048574], default 0

    last_slot_identifier
    :   The identifier of the most recently assigned action slot. The slot identifies which sub-set of the Action is considered to be for this constraint, and its identifier is used to find the right slot when assigning an Action.

        Type:
        :   string, default “”, (never None)

    max
    :   Maximum value for target channel range

        Type:
        :   float in [-1000, 1000], default 0.0

    min
    :   Minimum value for target channel range

        Type:
        :   float in [-1000, 1000], default 0.0

    mix_mode
    :   Specify how existing transformations and the action channels are combined

        - `REPLACE`
          Replace – Replace the original transformation with the action channels.
        - `BEFORE_FULL`
          Before Original (Full) – Apply the action channels before the original transformation, as if applied to an imaginary parent in Full Inherit Scale mode. Will create shear when combining rotation and non-uniform scale..
        - `BEFORE`
          Before Original (Aligned) – Apply the action channels before the original transformation, as if applied to an imaginary parent in Aligned Inherit Scale mode. This effectively uses Full for location and Split Channels for rotation and scale..
        - `BEFORE_SPLIT`
          Before Original (Split Channels) – Apply the action channels before the original transformation, handling location, rotation and scale separately.
        - `AFTER_FULL`
          After Original (Full) – Apply the action channels after the original transformation, as if applied to an imaginary child in Full Inherit Scale mode. Will create shear when combining rotation and non-uniform scale..
        - `AFTER`
          After Original (Aligned) – Apply the action channels after the original transformation, as if applied to an imaginary child in Aligned Inherit Scale mode. This effectively uses Full for location and Split Channels for rotation and scale..
        - `AFTER_SPLIT`
          After Original (Split Channels) – Apply the action channels after the original transformation, handling location, rotation and scale separately.

        Type:
        :   enum in [`'REPLACE'`, `'BEFORE_FULL'`, `'BEFORE'`, `'BEFORE_SPLIT'`, `'AFTER_FULL'`, `'AFTER'`, `'AFTER_SPLIT'`], default `'AFTER_FULL'`

    subtarget
    :   Armature bone, mesh or lattice vertex group, …

        Type:
        :   string, default “”, (never None)

    target
    :   Target object

        Type:
        :   [`Object`](bpy.types.Object.html#bpy.types.Object "bpy.types.Object")

    transform_channel
    :   Transformation channel from the target that is used to key the Action

        Type:
        :   enum in [`'LOCATION_X'`, `'LOCATION_Y'`, `'LOCATION_Z'`, `'ROTATION_X'`, `'ROTATION_Y'`, `'ROTATION_Z'`, `'SCALE_X'`, `'SCALE_Y'`, `'SCALE_Z'`], default `'ROTATION_X'`

    use_bone_object_action
    :   Bones only: apply the object’s transformation channels of the action to the constrained bone, instead of bone’s channels

        Type:
        :   boolean, default False

    use_eval_time
    :   Interpolate between Action Start and End frames, with the Evaluation Time slider instead of the Target object/bone

        Type:
        :   boolean, default False

    *classmethod* bl_rna_get_subclass(*id*, *default=None*, */*)
    :   Parameters:
        :   **id** (*str*) – The RNA type identifier.

        Returns:
        :   The RNA type or default when not found.

        Return type:
        :   [`bpy.types.Struct`](bpy.types.Struct.html#bpy.types.Struct "bpy.types.Struct") subclass

    *classmethod* bl_rna_get_subclass_py(*id*, *default=None*, */*)
    :   Parameters:
        :   **id** (*str*) – The RNA type identifier.

        Returns:
        :   The class or default when not found.

        Return type:
        :   type