Bend Physics Motor


Smooth Bend Physics Motor runs a simulated connected chain of bones using a relative curve element target dynamics model. This motor smooths out the dynamics motion over the chain of bones.

Installation Requirements

This motor requires 2 or more connected consecutive bones to be installed.


Smooth Bend Physics Motor defines a simulated chain of bones with forces between them both trying to preserve length and the overall shape of the curve along the bones.

The user sets the stiffness property to a high value if the overall shape of the curve needs to be preserved under motion. Lowering stiffness to 0 results in a free flowing material like rope or cloth. If rope or cloth are desired, make sure the physics mode is set to Motion.

If the physics mode is set to Motion, stretchStiffness becomes active and allows the user to tweak how stretchy the material is.

If the simulation is unstable or jittery, remember to increase the damping value. This makes the motion bleed energy faster and will result in more stability under high amounts of motion.

This motor has less degrees of freedom than the Bend Physics Motor since motion is smoothed or averaged out. Use the Bend Physics Motor instead if you require higher fidelity motion.

Animatable Properties

  • stiffness This determines how much of the curve's shape is preserved during simulation.

  • stretchStiffness This determines how stretchy the material is. Property is only active when the Physics Mode is set to Motion.

  • damping This determines how quickly energy bleeds from the system.

  • gravityFactor This determines the amount of gravity pulling on the simulated bones. Set this value to 0 if you do not want any gravitational effects.

  • fadeStiffnessRatio This determines how the stiffness value fades over the affected bone elements. You typically do not need to adjust this value.

Static Properties

  • Physics Mode There are 2 modes available. Stability is the mode typically used if all you want is a simulated curve that tries to preserve shape and remains stable under extreme motion. Motion is used when you want a more lively effect or if you want to use the stretchStiffness property for free flowing material like rope or cloth.