Force fields
Invisible fields that push, pull, swirl, or roughen nearby particles, with per-emitter routing so each field affects only what you want.
Open in the interactive manual →The interactive version has full-text search, a table of contents, and light/dark themes.
A force field influences particles within its radius: to swirl a cloud, suck it inward, blow it sideways, or rough it up. Add one with Create ▸ Force Field, then tune it in the Force Field section of Properties.
Field types
| Type | Effect |
|---|---|
| Vortex | Particles swirl around the field's axis. |
| Gravity well | Pulls particles inward toward the center. |
| Wind | Pushes particles in one direction. |
| Turbulence | Adds chaotic curl-noise jitter. |
| Pointer | The visitor's own cursor or finger. Moving or dragging pulls particles toward it and blows them along the direction of travel at the same time; a click or tap sends a ripple expanding outward from that spot. |
Aim a Wind or Vortex field by rotating the node: both use its local +Y axis. In the editor a field draws as a translucent sphere of influence (with an arrow for Wind/Vortex) so you can see its reach.
The Pointer field
This is the one field a visitor drives. It never steals the click, so orbiting, links and tap actions all keep working exactly as they did.
A cursor is a ray and a force needs a point, so you choose the depth it lands at with Cursor depth: Facing the viewer puts it on a plane through this node that always faces the camera (reachable anywhere on screen), and Flat, at this node's height puts it on a horizontal slice, drawn as a ring, for effects on a floor or a table. Either way the node's position is what sets that depth, so it is still worth placing.
- Magnet and Drag wind both multiply Strength. Set either to 0 to use only the other: magnet alone is a cloud that follows the cursor, wind alone is a wake that only appears while you move.
- Settle is how fast particles shed the speed this field gave them. Lower for a loose, floaty trail; higher for a tight cloud stuck to the cursor. At 0 nothing ever settles, so a long visit ends with everything either collapsed on the cursor or blown out of frame.
- Ripple push, Ripple speed and Ripple width shape the tap. Ripple push 0 turns taps off entirely. A ripple always finishes expanding even after the finger lifts, and retires once it reaches the field's Radius.
Field controls
- Field active: uncheck to switch the force off while keeping the node where it is. This is the control that turns a field on and off; the outliner eye only hides its gizmo, and particles keep feeling a hidden field.
- Radius: the sphere of influence.
- Strength: how hard it pushes. Negative strength inverts the field: gravity repels, wind reverses.
- Falloff: Constant, Linear, or Inverse-square across the radius.
- Frequency: turbulence only; the scale of the noise.
Affinity routing
By default a field affects every emitter in the scene. But each emitter has a Force-field affinity control (it appears once a field exists): uncheck "Affected by all fields" and tick only the fields you want this emitter to feel. So one vortex can spin your sparks while leaving the smoke alone.