A TorsionSpringConstraint applies torque based on a relative angle and relative angular velocity. It attempts to bring two axes from two parts together and is useful for hinged swinging doors with a spring-back effect.
Damping
The Damping value controls how fast the spring's oscillation dies down. A value of 0 allows the spring to oscillate endlessly, while higher values bring the spring to a rest more quickly.
Stiffness
Stiffness sets the torsional strength of the spring. Higher values create a spring that responds with more force.
Limits
Enabling the LimitsEnabled property exposes the MaxAngle value to restrict the spring's range within a cone; it also exposes the Restitution value which defines the elasticity of the attachments when they reach their limit.