Rope Gravity

Rope Gravity is one of the four stacking force nodes that live inside a Rope System. It does not simulate — it emits a Config structure that the container collects each frame and uploads to the GPU. Inside the solver, every enabled force is evaluated per particle, per substep, and the results are summed: add a Gravity, a Wind and a Turbulence node and cables feel all three simultaneously. A system accepts up to 16 force nodes.

The force is a pure constant acceleration: direction (normalized from Direction X/Y/Z) × Strength. Strength 1.0 corresponds to 2.5 Grafit units/s² — deliberately calibrated so that a 1-unit cable on a 2-unit-tall screen settles in a beat instead of drifting like it's on the moon. Because the force is a pure function of position and time (here, of neither), it can never inject energy that tears a cable — forces move ropes, only pin separation tears them.

Each Rope node scales its own response through Gravity Scale, so one gravity node can pull heavy and light cables differently in the same system. Setting Strength to exactly 0 removes the force from the frame entirely (the container drops zero-strength configs), and Enable off does the same.

Direction is normalized before use, so Direction 0, −10, 0 behaves identically to 0, −1, 0 — magnitude belongs to Strength. If all three components are zero, the default down direction is used.

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

• Normal hanging cables — drop one Rope Gravity next to your Rope node and leave the defaults: cables droop and swing naturally.
• Zero-G flotation — set Strength to 0.05 and add a Rope Turbulence node: cables drift like kelp or seaweed in slow water.
• Tilting world — LFO → Direction X while Direction Y stays at −1: gravity swings side to side and the whole bundle sways in sync, as if the room were rocking.
• Beat-driven jolt — Audio Beat Detection Kick → Math (multiply) → Strength through the system's wildcard + boundary: every kick yanks the cables downward.
• Upward smoke — Direction Y = 1 with a modest Strength and low Damping on the Rope: cables rise like ribbons in a draft.
• Depth pull — Direction Z positive with a Camera Distance around 3 on the system: cables lean toward the viewer and grow in perspective.

• Force nodes stack additively — there is no "master" gravity. Two Rope Gravity nodes with opposite directions cancel exactly.
• Per-cable weight belongs on the Rope node's Gravity Scale, not here: one gravity, many weights.
• A Strength of exactly 0 makes the node a no-op for that frame; use Enable if you want to keep the value while muting the force.
• Gravity can never tear a rope on its own — tearing is governed by pin separation versus Tear Distance on the Rope node, so animate the anchors if you want breaks.
• Extreme Strength (well above ~10) with few Segments can look stiff; raise the system's Quality tier rather than lowering the force.