Purpose

Force Field combines wind, curl noise, a vortex and attraction into a velocity grid. Use one field to direct several solvers, with each solver controlling how strongly it responds. The node generates flow values without solving a fluid simulation.

Use

Place Force Field in the Geometry view, under Solvers. For a clear first test, set Curl Amplitude and Vortex Strength to 0 and Wind to 1, 0, 0. Keep Resolution at 48 and Bound Size at 4. The preview should show a uniform direction within that domain.

On a receiving solver’s Resources page, add a velocity Connection and select this field’s velocity resource. Raise the receiver’s coupling control where it starts at 0, as it does on FLIP Liquid, Rigid, Soft Body and Deform. Connect Field Lines to the same resource for a separate view.

Inputs and outputs

The velocity output is a world-space vector grid. Its bounds come from Bound Size and Bound Center. Geometry is an optional declared input; the procedural field can be built without it.

A resource connection chooses the field. It does not set the receiving solver’s coupling strength or expand that solver’s domain.

Controls

• Wind sets the constant vector. Curl Amplitude and Frequency add noise; Octaves adds detail and Curl Drift moves the noise through space.
• Vortex Strength, Radius, Center and Axis shape rotation. Start by changing Strength while keeping the default Y axis.
• Positive Attract Strength pulls inward; negative values push outward. Attract Radius and Center locate the effect.
• Mask Radius at 0 disables the mask. A positive radius confines the field around Mask Center, with Mask Softness controlling the edge.
• Time Offset and Time Scale control procedural animation. Max Speed Clamp caps the resulting field speed.
• Resolution and bounds affect the field build. With Auto-Rebuild off, press Rebuild to apply pending structural changes. Preview controls change the displayed samples without changing field resolution.

Notes

The default field already combines wind, curl and a vortex. Isolate one contribution while learning what it does, then mix them.

Field strength and the receiving solver’s response are separate. If the preview looks right but the simulation does not move, check the velocity Connection, coupling value and domain placement.

Ports

Inputs

• geometry points

Outputs

• velocity velocity field
• preview lines
• preview_cd lines

Parameters

Force Field

Auto-Rebuild on Build Params (Autorebuild) Toggle op('force_field').par.Autorebuild

Default:

On

Options:

Off, On

Rebuild (Rebuildnow) Pulse op('force_field').par.Rebuildnow

Default:

None

Simulate (Simulate) Toggle op('force_field').par.Simulate

Default:

On

Options:

Off, On

Reset (Resetsolver) Pulse op('force_field').par.Resetsolver

Default:

None

Preview

Show Preview (Previewshow) Toggle op('force_field').par.Previewshow

Default:

On

Options:

Off, On

Preview Density (Previewdensity) Int op('force_field').par.Previewdensity

Default:

12

Range:

2 to 48

Preview Length (cells) (Previewlength) Float op('force_field').par.Previewlength

Default:

0.6

Range:

0 to 2

Outputs

Force Field Resource (Hdrforceout) Str op('force_field').par.Hdrforceout

Read only.

Default:

"" (Empty String)

Velocity Output Resource (Velocityname) Str op('force_field').par.Velocityname

Default:

force_vel

Domain

Domain (Hdrdomain) Str op('force_field').par.Hdrdomain

Read only.

Default:

"" (Empty String)

Resolution (Resolution) Int op('force_field').par.Resolution

Default:

48

Range:

8 to 256

Bound Size (cube) (Boundsize) Float op('force_field').par.Boundsize

Default:

4

Range:

0.1 to 20

Bound Center X (Boundcenterx) Float op('force_field').par.Boundcenterx

Default:

0

Range:

-100 to 100

Bound Center Y (Boundcentery) Float op('force_field').par.Boundcentery

Default:

0

Range:

-100 to 100

Bound Center Z (Boundcenterz) Float op('force_field').par.Boundcenterz

Default:

0

Range:

-100 to 100

Rebuild Field (Rebuild) Pulse op('force_field').par.Rebuild

Default:

None

Forces

Time (Hdrtime) Str op('force_field').par.Hdrtime

Read only.

Default:

"" (Empty String)

Time Offset (Time) Float op('force_field').par.Time

Default:

0

Range:

-100000 to 100000

Time Scale (Timescale) Float op('force_field').par.Timescale

Default:

1

Range:

-10 to 10

Wind / Curl (Hdrwind) Str op('force_field').par.Hdrwind

Read only.

Default:

"" (Empty String)

Wind (Windx) Float op('force_field').par.Windx

Default:

0.25

Range:

-100 to 100

Wind Y (Windy) Float op('force_field').par.Windy

Default:

0

Range:

-100 to 100

Wind Z (Windz) Float op('force_field').par.Windz

Default:

0

Range:

-100 to 100

Curl Amplitude (Curlamplitude) Float op('force_field').par.Curlamplitude

Default:

0.8

Range:

0 to 20

Curl Frequency (Curlfrequency) Float op('force_field').par.Curlfrequency

Default:

0.8

Range:

0.001 to 20

Curl Octaves (Curloctaves) Int op('force_field').par.Curloctaves

Default:

2

Range:

1 to 4

Curl Drift (Curldriftx) Float op('force_field').par.Curldriftx

Default:

0.15

Range:

-20 to 20

Curl Drift Y (Curldrifty) Float op('force_field').par.Curldrifty

Default:

0.08

Range:

-20 to 20

Curl Drift Z (Curldriftz) Float op('force_field').par.Curldriftz

Default:

0.04

Range:

-20 to 20

Max Speed Clamp (Maxspeed) Float op('force_field').par.Maxspeed

Default:

25

Range:

0 to 1000

Vortex

Vortex (Hdrvortex) Str op('force_field').par.Hdrvortex

Read only.

Default:

"" (Empty String)

Vortex Strength (Vortexstrength) Float op('force_field').par.Vortexstrength

Default:

1.5

Range:

-50 to 50

Vortex Radius (Vortexradius) Float op('force_field').par.Vortexradius

Default:

1.2

Range:

0.001 to 20

Vortex Center (Vortexcenterx) Float op('force_field').par.Vortexcenterx

Default:

0

Range:

-100 to 100

Vortex Center Y (Vortexcentery) Float op('force_field').par.Vortexcentery

Default:

0

Range:

-100 to 100

Vortex Center Z (Vortexcenterz) Float op('force_field').par.Vortexcenterz

Default:

0

Range:

-100 to 100

Vortex Axis (Vortexaxisx) Float op('force_field').par.Vortexaxisx

Default:

0

Range:

-1 to 1

Vortex Axis Y (Vortexaxisy) Float op('force_field').par.Vortexaxisy

Default:

1

Range:

-1 to 1

Vortex Axis Z (Vortexaxisz) Float op('force_field').par.Vortexaxisz

Default:

0

Range:

-1 to 1

Attractor

Attractor / Mask (Hdrattract) Str op('force_field').par.Hdrattract

Read only.

Default:

"" (Empty String)

Attract Strength (+in/-out) (Attractstrength) Float op('force_field').par.Attractstrength

Default:

0

Range:

-50 to 50

Attract Radius (Attractradius) Float op('force_field').par.Attractradius

Default:

1.5

Range:

0.001 to 20

Attract Center (Attractcenterx) Float op('force_field').par.Attractcenterx

Default:

0

Range:

-100 to 100

Attract Center Y (Attractcentery) Float op('force_field').par.Attractcentery

Default:

0

Range:

-100 to 100

Attract Center Z (Attractcenterz) Float op('force_field').par.Attractcenterz

Default:

0

Range:

-100 to 100

Mask Radius (0 = off) (Maskradius) Float op('force_field').par.Maskradius

Default:

0

Range:

0 to 20

Mask Softness (Masksoftness) Float op('force_field').par.Masksoftness

Default:

0.3

Range:

0.01 to 4

Mask Center (Maskcenterx) Float op('force_field').par.Maskcenterx

Default:

0

Range:

-100 to 100

Mask Center Y (Maskcentery) Float op('force_field').par.Maskcentery

Default:

0

Range:

-100 to 100

Mask Center Z (Maskcenterz) Float op('force_field').par.Maskcenterz

Default:

0

Range:

-100 to 100