Rope Wind

Rope Wind is one of the four stacking force nodes inside a Rope System. Every frame it emits a Config structure; the container gathers all enabled forces (up to 16) and the GPU solver evaluates and sums them per particle, per substep. Wind therefore combines freely with gravity, turbulence and attractors.

The force is direction (normalized from Direction X/Y/Z) × Strength, modulated by layered deterministic gust noise. Gust sets how deeply the gust layer modulates the base strength — 0 is a perfectly steady breeze, higher values swing between lulls and slams. Speed sets how fast the gust layers evolve on the simulation clock, so it follows the Rope System's Time Scale and External Time: freeze the system's time and the wind freezes with it, in the same phase.

Strength 1.0 equals 2.5 Grafit units/s², the same calibration as Rope Gravity — a strength of 0.6 (the default) is a noticeable but polite breeze against normal cable weight. Like all rope forces, wind is evaluated as a function of position and time and can never itself tear a cable; tearing is decided by pin separation on the Rope node.

The gust field is deterministic: the same simulation time produces the same gust, so a run replays identically — including the exact moment a big gust hits.

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

• Flag wall — a Rope with a row of Start Points along the top edge, Attach End off, plus Rope Gravity and Rope Wind (Gust 0.6): a wall of banners that ripples unevenly, never in lockstep.
• Audio-driven storm — Audio FFT low-band energy → system wildcard + → Rope Wind Strength: the bass drives how hard the wind blows while Gust keeps the motion organic.
• Direction sweep — LFO (sine, slow) → Direction X and a cosine LFO → Direction Z: the wind rotates around the scene and the cable bundle circles with it.
• Underwater current — Strength 0.15, Gust 0.8, Speed 0.2 with weak Rope Gravity: slow, heavy swells like a kelp forest.
• Frozen gust — set the Rope System's Time Scale to 0 mid-gust for a sculpted still, then back to 1: the wind resumes from the exact phase it paused at.
• Hair and tassels — short cables (Segments 12, Slack 1.05) with light wind and high Rope Damping: subtle flutter rather than whipping.

• Gust multiplies around the base Strength, so a high Gust with a low Strength produces long calms punctuated by pushes — often more convincing than a strong steady wind.
• Speed rides the Rope System clock (Time Scale / External Time), which is what makes wind scrub deterministically along with the rest of the physics.
• The direction vector is normalized: put magnitude in Strength, not in longer direction components.
• Stack two Rope Wind nodes with different Speed values and near-perpendicular directions for a convincingly turbulent, non-periodic air field — cheaper and more controllable than one extreme node.
• If cables whip through colliders under strong wind, raise the Rope System's Quality tier before lowering Strength.