Ball-and-Socket Wrist — 3D Joint Control

Spherical Joint • btPoint2PointConstraint • Spring Damping • 3D Joystick • Prosthetic Design

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Joint Geometry

Ball Radius 8 mm

Socket Radius 9 mm

Forearm Length 80 mm

Hand Palm Size 35 mm

Tendon Spring Properties

Spring Stiffness 150 N/m

Damping Coefficient 0.8

Max Rotation 90°

3D Joystick Control

Wrist Orientation

Pitch: 0°

Yaw: 0°

Roll: 0°

Motion State

Constraint

P2P

Distance

Tension

Velocity

m/s

Presets

Display

Transparency

Ball-socket visual

Show spring lines

Show force vectors

Ball-and-Socket Wrist Joint — 3D

Verts: — • Tris: — • DOF: 3

Joint Specifications

Ball Dia.	—
Socket Dia.	—
Clearance	—
Forearm Length	—
Palm Size	—
Total Volume	—
Material Density	—
Total Mass	—

Physics Constraint

Type	btPoint2PointConstraint
Bodies Linked	—
Pivot Point	—
Spring Stiffness	—
Damping Ratio	—
Constraint Error	—
Constraint Force	—

Ball-and-Socket Theory

btPoint2PointConstraint: Creates a "pin" constraint fixing two bodies at a point. Simulates a ball-and-socket by linking a hand surface point to the wrist joint center. Unlike a true spherical joint, it allows 3DOF rotation through compliance and spring forces.

Spring Damping: Adds elastic restoring torque + velocity-dependent damping. Models tendon pretension and biological resistance. Higher stiffness = stiffer tendon-driven motion.

Prosthetic Advantage: Motorized tendons can drive this constraint with precise 3D rotational control, enabling natural-feeling wrist flexion/extension, radial/ulnar deviation, and pronation/supination.

Export

Ready. Use the joystick to control wrist rotation.