Bone(bpy_struct)

base class — bpy_struct

class bpy.types.Bone(bpy_struct)

Bone in an Armature data-block

bbone_curveinx

X-axis handle offset for start of the B-Bone’s curve, adjusts curvature

Type

float in [-inf, inf], default 0.0

bbone_curveinz

Z-axis handle offset for start of the B-Bone’s curve, adjusts curvature

Type

float in [-inf, inf], default 0.0

bbone_curveoutx

X-axis handle offset for end of the B-Bone’s curve, adjusts curvature

Type

float in [-inf, inf], default 0.0

bbone_curveoutz

Z-axis handle offset for end of the B-Bone’s curve, adjusts curvature

Type

float in [-inf, inf], default 0.0

bbone_custom_handle_end

Bone that serves as the end handle for the B-Bone curve

Type

Bone

bbone_custom_handle_start

Bone that serves as the start handle for the B-Bone curve

Type

Bone

bbone_easein

Length of first Bezier Handle (for B-Bones only)

Type

float in [-inf, inf], default 1.0

bbone_easeout

Length of second Bezier Handle (for B-Bones only)

Type

float in [-inf, inf], default 1.0

bbone_handle_type_end

Selects how the end handle of the B-Bone is computed

• AUTO Automatic – Use connected parent and children to compute the handle.

• ABSOLUTE Absolute – Use the position of the specified bone to compute the handle.

• RELATIVE Relative – Use the offset of the specified bone from rest pose to compute the handle.

• TANGENT Tangent – Use the orientation of the specified bone to compute the handle, ignoring the location.

Type

enum in [‘AUTO’, ‘ABSOLUTE’, ‘RELATIVE’, ‘TANGENT’], default ‘AUTO’

bbone_handle_type_start

Selects how the start handle of the B-Bone is computed

• AUTO Automatic – Use connected parent and children to compute the handle.

• ABSOLUTE Absolute – Use the position of the specified bone to compute the handle.

• RELATIVE Relative – Use the offset of the specified bone from rest pose to compute the handle.

• TANGENT Tangent – Use the orientation of the specified bone to compute the handle, ignoring the location.

Type

enum in [‘AUTO’, ‘ABSOLUTE’, ‘RELATIVE’, ‘TANGENT’], default ‘AUTO’

bbone_handle_use_ease_end

Multiply the B-Bone Ease Out channel by the local Y scale value of the end handle. This is done after the Scale Easing option and isn’t affected by it

Type

boolean, default False

bbone_handle_use_ease_start

Multiply the B-Bone Ease In channel by the local Y scale value of the start handle. This is done after the Scale Easing option and isn’t affected by it

Type

boolean, default False

bbone_handle_use_scale_end

Multiply B-Bone Scale Out channels by the local scale values of the end handle. This is done after the Scale Easing option and isn’t affected by it

Type

boolean array of 3 items, default (False, False, False)

bbone_handle_use_scale_start

Multiply B-Bone Scale In channels by the local scale values of the start handle. This is done after the Scale Easing option and isn’t affected by it

Type

boolean array of 3 items, default (False, False, False)

bbone_rollin

Roll offset for the start of the B-Bone, adjusts twist

Type

float in [-inf, inf], default 0.0

bbone_rollout

Roll offset for the end of the B-Bone, adjusts twist

Type

float in [-inf, inf], default 0.0

bbone_scalein

Scale factors for the start of the B-Bone, adjusts thickness (for tapering effects)

Type

float array of 3 items in [-inf, inf], default (1.0, 1.0, 1.0)

bbone_scaleout

Scale factors for the end of the B-Bone, adjusts thickness (for tapering effects)

Type

float array of 3 items in [-inf, inf], default (1.0, 1.0, 1.0)

bbone_segments

Number of subdivisions of bone (for B-Bones only)

Type

int in [1, 32], default 0

bbone_x

B-Bone X size

Type

float in [-inf, inf], default 0.0

bbone_z

B-Bone Z size

Type

float in [-inf, inf], default 0.0

children

Bones which are children of this bone

Type

bpy_prop_collection of Bone, (readonly)

envelope_distance

Bone deformation distance (for Envelope deform only)

Type

float in [0, 1000], default 0.0

envelope_weight

Bone deformation weight (for Envelope deform only)

Type

float in [0, 1000], default 0.0

head

Location of head end of the bone relative to its parent

Type

float array of 3 items in [-inf, inf], default (0.0, 0.0, 0.0), (readonly)

head_local

Location of head end of the bone relative to armature

Type

float array of 3 items in [-inf, inf], default (0.0, 0.0, 0.0), (readonly)

head_radius

Radius of head of bone (for Envelope deform only)

Type

float in [-inf, inf], default 0.0

hide

Bone is not visible when it is not in Edit Mode (i.e. in Object or Pose Modes)

Type

boolean, default False

hide_select

Bone is able to be selected

Type

boolean, default False

inherit_scale

Specifies how the bone inherits scaling from the parent bone

• FULL Full – Inherit all effects of parent scaling.

• FIX_SHEAR Fix Shear – Inherit scaling, but remove shearing of the child in the rest orientation.

• ALIGNED Aligned – Rotate non-uniform parent scaling to align with the child, applying parent X scale to child X axis, and so forth.

• AVERAGE Average – Inherit uniform scaling representing the overall change in the volume of the parent.

• NONE None – Completely ignore parent scaling.

• NONE_LEGACY None (Legacy) – Ignore parent scaling without compensating for parent shear. Replicates the effect of disabling the original Inherit Scale checkbox.

Type

enum in [‘FULL’, ‘FIX_SHEAR’, ‘ALIGNED’, ‘AVERAGE’, ‘NONE’, ‘NONE_LEGACY’], default ‘FULL’

layers

Layers bone exists in

Type

boolean array of 32 items, default (False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False)

length

Length of the bone

Type

float in [-inf, inf], default 0.0, (readonly)

matrix

3x3 bone matrix

Type

float multi-dimensional array of 3 * 3 items in [-inf, inf], default ((0.0, 0.0, 0.0), (0.0, 0.0, 0.0), (0.0, 0.0, 0.0)), (readonly)

matrix_local

4x4 bone matrix relative to armature

Type

float multi-dimensional array of 4 * 4 items in [-inf, inf], default ((0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0)), (readonly)

name

Type

string, default “”, (never None)

parent

Parent bone (in same Armature)

Type

Bone, (readonly)

select

Type

boolean, default False

select_head

Type

boolean, default False

select_tail

Type

boolean, default False

show_wire

Bone is always displayed in wireframe regardless of viewport shading mode (useful for non-obstructive custom bone shapes)

Type

boolean, default False

tail

Location of tail end of the bone relative to its parent

Type

float array of 3 items in [-inf, inf], default (0.0, 0.0, 0.0), (readonly)

tail_local

Location of tail end of the bone relative to armature

Type

float array of 3 items in [-inf, inf], default (0.0, 0.0, 0.0), (readonly)

tail_radius

Radius of tail of bone (for Envelope deform only)

Type

float in [-inf, inf], default 0.0

use_connect

When bone has a parent, bone’s head is stuck to the parent’s tail

Type

boolean, default False, (readonly)

use_cyclic_offset

When bone doesn’t have a parent, it receives cyclic offset effects (Deprecated)

Type

boolean, default False

use_deform

Enable Bone to deform geometry

Type

boolean, default False

use_endroll_as_inroll

Add Roll Out of the Start Handle bone to the Roll In value

Type

boolean, default False

use_envelope_multiply

When deforming bone, multiply effects of Vertex Group weights with Envelope influence

Type

boolean, default False

use_inherit_rotation

Bone inherits rotation or scale from parent bone

Type

boolean, default False

use_inherit_scale

DEPRECATED: Bone inherits scaling from parent bone

Type

boolean, default False

use_local_location

Bone location is set in local space

Type

boolean, default False

use_relative_parent

Object children will use relative transform, like deform

Type

boolean, default False

use_scale_easing

Multiply the final easing values by the Scale In/Out Y factors

Type

boolean, default False

basename

The name of this bone before any ‘.’ character

(readonly)

center

The midpoint between the head and the tail.

(readonly)

children

A list of all the bones children.

Note

Takes O(len(bones)) time.

(readonly)

children_recursive

A list of all children from this bone.

Note

Takes O(len(bones)**2) time.

(readonly)

children_recursive_basename

Returns a chain of children with the same base name as this bone. Only direct chains are supported, forks caused by multiple children with matching base names will terminate the function and not be returned.

Note

Takes O(len(bones)**2) time.

(readonly)

parent_recursive

A list of parents, starting with the immediate parent

(readonly)

vector

The direction this bone is pointing. Utility function for (tail - head)

(readonly)

x_axis

Vector pointing down the x-axis of the bone.

(readonly)

y_axis

Vector pointing down the y-axis of the bone.

(readonly)

z_axis

Vector pointing down the z-axis of the bone.

(readonly)

evaluate_envelope(point)

Calculate bone envelope at given point

Parameters

point (float array of 3 items in [-inf, inf]) – Point, Position in 3d space to evaluate

Returns

Factor, Envelope factor

Return type

float in [-inf, inf]

convert_local_to_pose(matrix, matrix_local, parent_matrix=((0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0)), parent_matrix_local=((0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0), (0.0, 0.0, 0.0, 0.0)), invert=False)

Transform a matrix from Local to Pose space (or back), taking into account options like Inherit Scale and Local Location. Unlike Object.convert_space, this uses custom rest and pose matrices provided by the caller. If the parent matrices are omitted, the bone is assumed to have no parent.

Parameters

• matrix (float multi-dimensional array of 4 * 4 items in [-inf, inf]) – The matrix to transform

• matrix_local (float multi-dimensional array of 4 * 4 items in [-inf, inf]) – The custom rest matrix of this bone (Bone.matrix_local)

• parent_matrix (float multi-dimensional array of 4 * 4 items in [-inf, inf], (optional)) – The custom pose matrix of the parent bone (PoseBone.matrix)

• parent_matrix_local (float multi-dimensional array of 4 * 4 items in [-inf, inf], (optional)) – The custom rest matrix of the parent bone (Bone.matrix_local)

• invert (boolean, (optional)) – Convert from Pose to Local space

Returns

The transformed matrix

Return type

float multi-dimensional array of 4 * 4 items in [-inf, inf]

This method enables conversions between Local and Pose space for bones in the middle of updating the armature without having to update dependencies after each change, by manually carrying updated matrices in a recursive walk.

def set_pose_matrices(obj, matrix_map):
    "Assign pose space matrices of all bones at once, ignoring constraints."

    def rec(pbone, parent_matrix):
        matrix = matrix_map[pbone.name]

        ## Instead of:
        # pbone.matrix = matrix
        # bpy.context.view_layer.update()

        # Compute and assign local matrix, using the new parent matrix
        if pbone.parent:
            pbone.matrix_basis = pbone.bone.convert_local_to_pose(
                matrix,
                pbone.bone.matrix_local,
                parent_matrix=parent_matrix,
                parent_matrix_local=pbone.parent.bone.matrix_local,
                invert=True
            )
        else:
            pbone.matrix_basis = pbone.bone.convert_local_to_pose(
                matrix,
                pbone.bone.matrix_local,
                invert=True
            )

        # Recursively process children, passing the new matrix through
        for child in pbone.children:
            rec(child, matrix)

    # Scan all bone trees from their roots
    for pbone in obj.pose.bones:
        if not pbone.parent:
            rec(pbone, None)

classmethod MatrixFromAxisRoll(axis, roll)

Convert the axis + roll representation to a matrix

Parameters

• axis (float array of 3 items in [-inf, inf], (never None)) – The main axis of the bone (tail - head)

• roll (float in [-inf, inf]) – The roll of the bone

Returns

The resulting orientation matrix

Return type

float multi-dimensional array of 3 * 3 items in [-inf, inf]

classmethod AxisRollFromMatrix(matrix, axis=(0.0, 0.0, 0.0))

Convert a rotational matrix to the axis + roll representation. Note that the resulting value of the roll may not be as expected if the matrix has shear or negative determinant.

Parameters

• matrix (float multi-dimensional array of 3 * 3 items in [-inf, inf], (never None)) – The orientation matrix of the bone

• axis (float array of 3 items in [-inf, inf], (optional)) – The optional override for the axis (finds closest approximation for the matrix)

Return (result_axis, result_roll)

result_axis, The main axis of the bone, float array of 3 items in [-inf, inf]

result_roll, The roll of the bone, float in [-inf, inf]

parent_index(parent_test)

The same as ‘bone in other_bone.parent_recursive’ but saved generating a list.

translate(vec)

Utility function to add vec to the head and tail of this bone

classmethod bl_rna_get_subclass(id, default=None)

Parameters

id (string) – 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 (string) – 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_resolve bpy_struct.pop bpy_struct.property_overridable_library_set bpy_struct.property_unset bpy_struct.type_recast bpy_struct.values

References

bpy.context.bone Armature.bones ArmatureBones.active Bone.bbone_custom_handle_end

Bone.bbone_custom_handle_start Bone.children Bone.parent PoseBone.bone