What is the Bone Properties Tab in Blender?

The Bone Properties tab in Blender is a dedicated settings panel used to control and customize individual bones within a 3D armature. Located in the Properties Editor when an armature is selected, this tab allows animators and riggers to adjust a specific active bone's transforms, parenting relationships, deformation behavior, inverse kinematics (IK) limits, and custom viewport appearances. Understanding this tab is essential for creating functional character rigs and precise 3D animations.

Key Features and Panels in Bone Properties

1. Transform

The Transform panel controls the active bone's local positioning, rotation, and scale.

  • Mode: Allows you to choose the rotation mode, such as Quaternion (WXYZ) for avoiding gimbal lock, or various Euler angles (XYZ, ZXY, etc.) for simpler animation curves.
  • Location, Rotation, and Scale: Displays exact numeric values for the bone's current state relative to its parent or local space.

2. Relations

This panel manages how the selected bone interacts with other bones in the same armature hierarchy.

  • Parent: Sets or changes the parent bone.
  • Connected: Keeps the head of the child bone attached directly to the tail of the parent bone.
  • Inherit Rotation / Scale: Toggle options to determine whether the bone automatically inherits rotation or scaling transforms from its parent.
  • Local Location: Ensures the bone's movement relies on its local coordinate system rather than the parent's.

3. Inverse Kinematics (IK)

When using IK constraints to animate limbs (like legs or arms bending naturally), the Inverse Kinematics panel defines how the bone behaves within the IK chain.

  • Locking Axes: Restricts movement along specific X, Y, or Z axes.
  • Stiffness: Controls how resistant the bone is to bending when the IK target moves.
  • Limits: Sets min/max angle limits for natural joint rotation (e.g., preventing an elbow from bending backward).
  • Stretch: Allows the bone to lengthen along its axis when the IK target is pulled beyond the rig's standard reach.

4. Deform

The Deform panel determines how the bone influences attached 3D meshes during animation.

  • Deform Checkbox: Disabling this prevents the bone from affecting the mesh entirely, which is ideal for control bones, targets, or mechanical helpers.
  • Envelope: Adjusts the distance and influence radius of the bone's automatic weighting volume.
  • Bending Distance: Controls the curvature influence area when using Envelope weights.

5. Bendy Bones (B-Bones)

Bendy Bones split a single bone into multiple visual segments to create smooth, curved deformations for organic objects like tails, tentacles, or spine setups.

  • Segments: Increases the number of sub-segments within the single bone.
  • Curve In/Out: Controls the easing, roll, scale, and offset at the start (head) and end (tail) of the bone.

6. Viewport Display

This section helps keep rigs organized and easy to navigate visually.

  • Custom Object: Replaces the default bone shape (octahedral, stick, etc.) with a custom 3D mesh (e.g., a circle or box) to create user-friendly animator controls.
  • Scale / Offset: Adjusts the display size and alignment of the custom shape without altering the actual bone transforms.
  • Wireframe: Forces the custom shape to render as a wireframe for clearer visibility over the mesh.