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F379 — continuous force field acting on a fleet of bodies each frame, computed from each body's distance to a moving (or static) field centre. Replaces JS-spring CSS effects (e.g. `cursorProximityWrite`) when targets are physics-bound elements: keeps everything inside ONE physics simulation, so cursor pushes and ball impacts compose cleanly through the engine instead of fighting at the CSS layer.
Type physicsForceFieldCategory solversContext sharedDynamic ports noCompound no
Inputs
| Port | Type | Description |
|---|---|---|
world | any | World |
bodyIds | floatArray | Fleet to act on. Wire from `physicsStaticBodyEach.bodyIds` or `physicsBodyStagger.bodyIds`. |
centerX | float | Field source x. Viewport coords when `frameSelector` is set; otherwise body coords. Wire `pointer.x` for a cursor-driven field. |
centerY | float | Center Y (px) |
enabled | float | Enabled |
Outputs
| Port | Type | Description |
|---|---|---|
| - | - | No ports declared. |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
mode | enum | "repel" | Mode options repel, attract |
radius | float | 200 | Effective range. Bodies further than this from the centre receive zero force. min 0; step 10 |
strength | float | 50 | Peak force magnitude at the centre. Decays to 0 at the radius edge per `falloff`. Tune with respect to body density × mass. step 5 |
falloff | enum | "linear" | Falloff options linear, inverse, inverseSquare |
frameSelector | string | "" | Optional CSS selector for viewport→body coord transform on `centerX/Y`. Set when wiring raw `pointer.x/y` so the field centre tracks the visible cursor in the world's coord space. Leave empty when `centerX/Y` are sourced from another physics body or already in body coords. |
motionGateMinSpeed | float | 0 | When > 0, the field stops applying force whenever the centre's frame-to-frame speed drops below this threshold. Mitigates iterative-solver creep — sustained force on a stack of bodies pinned against a corner will eventually squeeze them through walls; gating on cursor motion lets the user stop creeping by simply holding still. 0 = always-on (original behaviour, fine for non-stacked scenes). 50 px/s = "broom" feel: silent when cursor is held, alive when it moves. Use 0 if the field is a magnet on a static scene where you want force even when the cursor is parked. min 0; step 10 |
Use cases
- Cursor repulsor — wire `pointer.x/y → centerX/centerY`, `physicsStaticBodyEach.bodyIds → bodyIds`, set `mode: repel`, `radius: 200`. Cursor pushes letters/cards/grid items away with smooth falloff.
- Magnetic cursor — same wiring, `mode: attract`, `falloff: inverse`. Bodies suck toward cursor; pair with a stiff spring tether for snap-back.
- Static gravity well — `centerX/Y` driven by literal coords (not pointer). Bodies orbit / fall toward the well.
- Ball-pit nudge — multiple force fields (one per cursor / one per touch point) target the same body fleet; their contributions stack additively at the physics layer.
Related nodes
Envelope
Use physicsForceField as the node type inside a graph node envelope. Add id, optional params, optional connections, and optional activeWhen based on the guide context.
Generated source
Registry faster-motion-docs/node-registry.jsonCategory page /help/faster-motion/faster-motion-node-category-solvers/