Rope Turbulence

Rope Turbulence is one of the four stacking force nodes inside a Rope System. It emits a Config structure each frame; the container gathers all enabled forces (up to 16) and the GPU solver evaluates and sums them per particle, per substep.

The field is analytic curl noise and, crucially, a pure function of position and simulation time. That means two things. First, it is deterministic: the same spot at the same simulation time always yields the same force vector, for every cable that visits it — a replay is bit-identical. Second, being divergence-free and position-pure, it can never inject the kind of runaway energy that would tear a cable; tearing remains a matter of pin separation on the Rope node.

Scale controls the spatial frequency of the field: small values produce large, lazy vortices that move whole cables together; large values produce tight eddies that ripple along a single cable. Speed drives how fast the field itself evolves, on the Rope System's clock — so Time Scale and External Time scrub the turbulence exactly like the rest of the physics. Strength scales the magnitude, with 1.0 equal to 2.5 Grafit units/s², the same calibration as the other rope forces.

Because the field is coherent in space, neighbouring cables move in sympathy rather than independently — the difference between a flock and static.

Output: Config (structure) — collected automatically by the parent Rope System.

• Underwater tentacles — weak Rope Gravity (Strength 0.15) + Rope Turbulence (Strength 0.6, Scale 0.4, Speed 0.3) on free-ended cables: slow, coherent undulation.
• Static field sculpting — set Speed to 0 and raise Scale: the cables settle into a fixed, frozen swirl shape you can then rotate with the system's Rotation Z.
• Music-reactive chaos — Audio Analysis High band → system wildcard + → Strength: cymbals and hats add high-frequency jitter while the low end drives gravity or wind.
• Two-layer air — one Turbulence node with Scale 0.2 / Speed 0.15 for broad drift, a second with Scale 2.0 / Speed 1.2 and low Strength for surface shimmer: a convincing multi-octave field.
• Deterministic replay for capture — drive the system's External Time from a Timer while rendering: turbulence replays identically frame for frame, so multi-pass captures line up perfectly.
• Hair in a breeze — pair with Rope Wind: wind gives the direction, turbulence breaks the uniformity so strands separate instead of moving as a slab.

• Scale is the character knob. If turbulence looks like noise rather than motion, lower it — big vortices read as intention, small ones as vibration.
• Position purity means turbulence is safe at high strengths: it will not blow a cable apart, it will only fling it further.
• Turbulence follows the Rope System clock, so freezing Time Scale freezes the field in phase — perfect for a hard stop on a beat.
• Very high Scale with a low Segments count on the Rope wastes the detail; give cables 24+ segments before pushing fine eddies.
• Combining turbulence with a Rope Attract set to a tall narrow rectangle produces cables that swirl but keep returning to a column — the classic "spirit" look.