SpringFX adds physically based secondary motion to bone chains: hair, ponytails, ears, tails, skirts, coats, accessories and soft tissue. It is tuned for MetaHumans and the UE5 body skeleton, and works on any skeletal mesh.

WHY SPRINGFX

- Analytic damped-oscillator solver: stable at any stiffness and frame rate, no explosions and no frequency capping.

- Swing-only spherical pendulum rotation: no parasitic twist, the animated twist is preserved.

- Rotation and Location springs, with stiffness in Hz and damping as a real damping ratio.

- "Honey drag" fix: choose World, Rest Frame or Blended damping space.

- Sphere, capsule and plane colliders with channel masks.

- Wind (engine wind sources), deterministic noise and gusts.

- Swing cone limits with soft walls.

WORKFLOW

- One SpringFX node in the Anim Graph, placed after your final pose.

- SpringFX Profile data asset: share one setup across every Animation Blueprint of a character.

- Auto Setup Chains detects hair / tail / ear / skirt / cloth / accessory chains by bone name and applies the matching preset. Facial and control bones are skipped.

- Generate Colliders builds the standard UE5 / MetaHuman body collider set.

- 12 built-in presets (Hair Soft/Stiff/Long, Ears, Tail, Cloth, Skirt, Accessory, Necklace, Chest, Belly, Antenna).

- Control Rig unit (SpringFX Chain) running the same solver.

- Bake to Animation Sequence with loop-aware pre-roll, for cinematics and Movie Render Queue.

- Blueprint API and JSON import/export of profiles.

- Distance LOD, cull distance and teleport detection.

INCLUDED

- Full C++ source (Runtime + Editor modules).

- Template profile with the UE5 body collider set.

- README and Quick Start documentation.

Supported: Unreal Engine 5.8, Win64.