Radial Force

Attraction / repulsion vector field — points flow toward or away from a center. The "gravity / magnet" primitive for physics-like motion without the full Physics roadmap.

Category: Fields Menu path: Fields > Radial Force

Ports

Port	Type	Direction	Description
scalar	scalar	output	Force magnitude at comp center (CPU value)
vec2	vec2	output	Force vector at comp center (CPU value)
scalarField	scalarField	output	Magnitude field (
vectorField	vectorField	output	Radial force field (primary output)

Parameters

Param	Type	Default	Description
center	vec2	(0, 0)	Attraction/repulsion origin
strength	scalar	1.0	Signed peak magnitude. Positive = push (points flee), negative = pull (points attract). Keyframeable
radius	scalar	200	Distance at which the falloff's t = 1 value applies
falloffType	enum	Linear	Linear · InverseDistance · InverseSquare · Custom
falloff	curveRamp	linear 1→0	Only active when falloffType = Custom. Maps normalized distance to a multiplier

Expose Channels

When enabled (E button on node header), adds input ports that override params via edge connections:

Port	Type	Overrides
center_in	vec2	center
strength_in	scalar	strength
radius_in	scalar	radius

How It Works

At each sample point, Radial Force computes the unit radial direction (sample minus center, normalized) and multiplies by a signed magnitude sign(strength) × |strength| × falloff(t), where t = clamp(distance / radius, 0, 1).

Built-in falloff functions:

• Linear — 1 - t. Smooth decay from full strength at center to 0 at the edge.
• InverseDistance — 1 / (1 + 9t). Gentle decay; approximates real-world 1/r fields.
• InverseSquare — 1 / (1 + 99t²). Sharp decay; gravity / light-attenuation character.
• Custom — uses the falloff CurveRamp directly.

At the exact center, the direction is undefined so the vector is zero; the magnitude field peaks there.

Usage Examples

Basic: Attractor

Grid → PointAdvect ← RadialForce.vectorField → DrawPoints → Output. Set strength to a negative value — points get pulled toward the center.

Basic: Scatterer

Same graph with positive strength — points flee outward.

Creative: Spiral in

Combine with a Vortex at the same center via FieldMath Add on the two vectorField outputs. Points spiral inward (pull + tangential flow).

Creative: Anti-gravity ring

Use falloffType = Custom and draw a CurveRamp that's 0 at the center, spikes around 0.5, then drops to 0. Points caught in a narrow annular band get pushed outward, leaving a calm eye.

Tips

• Signed strength avoids needing two nodes or a separate "direction" toggle — just negate to switch push/pull.
• InverseSquare gives a much steeper falloff than InverseDistance — if your effect concentrates too tightly at the center, drop to InverseDistance or Linear.
• The scalarField output is useful as a mask: combine via FieldMath Multiply with another field to concentrate an effect around a point.

Related Nodes

• Vortex — tangential swirl; pairs naturally for spiral motion
• PointAdvect — consumes the vectorField to move points along the force
• DistanceField — for shape-based (not point-based) distance fields
• FieldMath — combine radial + vortex + noise forces