ActionSlot(bpy_struct)

Action Slots organize animation data within an action. Each action has slots with specific animation data. An animated data-block specifies an action and a slot, determining the animation data it uses. See the Blender Manual for how Action Slots are used, or the technical documentation for details on the animation system’s architecture.

Create & Access an Action Slot

To get started with Action Slots, you can easily create them by inserting a keyframe on an object. When you do this, Blender automatically creates an Action & Slot for that data-block.

import bpy

# Assume Suzanne mesh is present in the scene.
suzanne = bpy.data.objects["Suzanne"]

# Create animation data and an action for Suzanne:
# Slot will be automatically created.
suzanne.keyframe_insert("location", index=0)

# Action slots can be accessed like this:
action = suzanne.animation_data.action
for slot in action.slots:
    print(f"Slot Identifier {slot.identifier!r} "
          f"with name {slot.name_display!r} "
          f"targets ID type {slot.target_id_type!r}")

Manually Create an Action Slot

If required you can also manually create Action Slots on an Action. Note the target_id_type that matches the data-block type. Identifiers start with a prefix based on the ID type, e.g. “OB” for objects, followed by the name. There can be identifiers like OBSuzanne and MESuzanne and the name (Suzanne) can be shared between them. This is intentional, so that the slots and the datablocks can have the same name.

# Actions creation.
action = bpy.data.actions.new("SuzanneAction")

# Creation of slots requires an ID type and a name.
slot = action.slots.new(id_type='OBJECT', name="Suzanne")
print(f"slot type={slot.target_id_type!r} "
      f"name={slot.name_display!r} "
      f"identifier={slot.identifier!r}")

# Output:
#   slot type=OBJECT name=Suzanne identifier=OBSuzanne

Explicitly Assigning Action Slots

An action slot is compatible with a data-block if the slot’s target_id_type matches the data-block’s type. If there are multiple slots on the Action, and you want to just pick the first one that’s compatible, use the following code. anim_data.action_suitable_slots can be used after the Action has been assigned; it is a list of action slots of that Action, but only the ones that are actually compatible with the owner of anim_data (in this case, Suzanne).

# If there are multiple slots on the Action, pick the first one that's compatible
anim_data = suzanne.animation_data_create()
anim_data.action = action
assert anim_data.action_suitable_slots, "expecting at least one suitable slot"
anim_data.action_slot = anim_data.action_suitable_slots[0]

Finding Action Slot Users

To return a list of the data-blocks that are animated by a specific slot of an Action, use the users() method of the ActionSlot.

# Iterate through all actions in the Blender data.
print("Action & slot users:")
for action in bpy.data.actions:
    for slot in action.slots:
        # Return the data-blocks that are animated by this slot of this action
        users = slot.users()
        print(f"{action.name:20} slot={slot.identifier:12s} users: {users}")

base class — bpy_struct

class bpy.types.ActionSlot(bpy_struct)

Identifier for a set of channels in this Action, that can be used by a data-block to specify what it gets animated by

active

Whether this is the active slot, can be set by assigning to action.slots.active

Type:

boolean, default False, (readonly)

handle

Number specific to this Slot, unique within the Action. This is used, for example, on a ActionKeyframeStrip to look up the ActionChannelbag for this Slot

Type:

int in [-inf, inf], default 0, (readonly)

identifier

Used when connecting an Action to a data-block, to find the correct slot handle. This is the display name, prefixed by two characters determined by the slot’s ID type

Type:

string, default “”, (never None)

name_display

Name of the slot, for display in the user interface. This name combined with the slot’s data-block type is unique within its Action

Type:

string, default “”, (never None)

select

Selection state of the slot

Type:

boolean, default False

show_expanded

Expanded state of the slot

Type:

boolean, default False

target_id_type

Type of data-block that this slot is intended to animate; can be set when ‘UNSPECIFIED’ but is otherwise read-only

• ACTION Action.

• ARMATURE Armature.

• BRUSH Brush.

• CACHEFILE Cache File.

• CAMERA Camera.

• COLLECTION Collection.

• CURVE Curve.

• CURVES Curves.

• FONT Font.

• GREASEPENCIL Grease Pencil.

• GREASEPENCIL_V3 Grease Pencil v3.

• IMAGE Image.

• KEY Key.

• LATTICE Lattice.

• LIBRARY Library.

• LIGHT Light.

• LIGHT_PROBE Light Probe.

• LINESTYLE Line Style.

• MASK Mask.

• MATERIAL Material.

• MESH Mesh.

• META Metaball.

• MOVIECLIP Movie Clip.

• NODETREE Node Tree.

• OBJECT Object.

• PAINTCURVE Paint Curve.

• PALETTE Palette.

• PARTICLE Particle.

• POINTCLOUD Point Cloud.

• SCENE Scene.

• SCREEN Screen.

• SOUND Sound.

• SPEAKER Speaker.

• TEXT Text.

• TEXTURE Texture.

• VOLUME Volume.

• WINDOWMANAGER Window Manager.

• WORKSPACE Workspace.

• WORLD World.

• UNSPECIFIED Unspecified – Not yet specified. When this slot is first assigned to a data-block, this will be set to the type of that data-block.

Type:

enum in ['ACTION', 'ARMATURE', 'BRUSH', 'CACHEFILE', 'CAMERA', 'COLLECTION', 'CURVE', 'CURVES', 'FONT', 'GREASEPENCIL', 'GREASEPENCIL_V3', 'IMAGE', 'KEY', 'LATTICE', 'LIBRARY', 'LIGHT', 'LIGHT_PROBE', 'LINESTYLE', 'MASK', 'MATERIAL', 'MESH', 'META', 'MOVIECLIP', 'NODETREE', 'OBJECT', 'PAINTCURVE', 'PALETTE', 'PARTICLE', 'POINTCLOUD', 'SCENE', 'SCREEN', 'SOUND', 'SPEAKER', 'TEXT', 'TEXTURE', 'VOLUME', 'WINDOWMANAGER', 'WORKSPACE', 'WORLD', 'UNSPECIFIED'], default 'UNSPECIFIED'

target_id_type_icon

Type:

int in [-inf, inf], default 0, (readonly)

users()

Return the data-blocks that are animated by this slot of this action

Returns:

users

Return type:

bpy_prop_collection of ID

duplicate()

Duplicate this slot, including all the animation data associated with it

Returns:

Duplicated Slot, The slot created by duplicating this one

Return type:

ActionSlot

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 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

Inherited Properties

bpy_struct.id_data

Inherited Functions

bpy_struct.as_pointer bpy_struct.driver_add bpy_struct.driver_remove bpy_struct.get bpy_struct.id_properties_clear bpy_struct.id_properties_ensure bpy_struct.id_properties_ui bpy_struct.is_property_hidden bpy_struct.is_property_overridable_library bpy_struct.is_property_readonly bpy_struct.is_property_set bpy_struct.items

bpy_struct.keyframe_delete bpy_struct.keyframe_insert bpy_struct.keys bpy_struct.path_from_id bpy_struct.path_from_module bpy_struct.path_resolve bpy_struct.pop bpy_struct.property_overridable_library_set bpy_struct.property_unset bpy_struct.rna_ancestors bpy_struct.type_recast bpy_struct.values

References

Action.slots ActionChannelbag.slot ActionChannelbags.new ActionConstraint.action_slot ActionConstraint.action_suitable_slots ActionKeyframeStrip.channelbag ActionKeyframeStrip.key_insert ActionSlot.duplicate

ActionSlots.active ActionSlots.new ActionSlots.remove AnimData.action_slot AnimData.action_suitable_slots NlaStrip.action_slot NlaStrip.action_suitable_slots