Rope Attract

Rope Attract is one of the four stacking force nodes inside a Rope System. Each 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. Attraction combines freely with gravity, wind and turbulence — a classic combination is gravity down plus a repeller in the middle, so cables part around an invisible obstacle.

Two zone shapes, chosen by the Shape dropdown, with the inspector hiding the ports that don't apply:

The rectangle mode is the reason this node exists in two flavours: a tall, narrow rectangle (the defaults, Size X 0.3 × Size Y 1.6) reaches far vertically while keeping a tight lateral grip, so it can lift cables lying on a floor collider from a long way off without dragging everything sideways. A circle is the natural choice for a general gravity well.

Strength follows the same calibration as the other rope forces: 1.0 corresponds to 2.5 Grafit units/s². Negative values invert the field into a repeller. Like all rope forces, attraction is a pure function of position — it can never tear a cable on its own.

Show draws the zone live in the render view: the shape outline plus directional arrows indicating pull or push, so you can position the attractor by eye instead of by trial and error.

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

• Gathering column — Rectangle shape, Size X 0.25, Size Y 1.8, Strength 1.5, plus Rope Gravity: cables from all over the frame rise and braid into a vertical column.
• Invisible obstacle — Circle, Radius 0.6, Strength −1.2 at frame center: a hanging curtain of cables parts around an empty space in the middle.
• Mouse magnet — Mouse node X/Y → system wildcard + → Position X / Position Y: cables chase the cursor around the viewport, with Show on so the pull radius is visible while performing.
• Beat pulse — Audio Beat Detection Kick probability → Math (scale to −2…2) → Strength: cables are yanked in on the beat and released between hits.
• Two-pole field — one attractor at Position X −0.7 and a repeller at +0.7: cables flow from one pole to the other, a visible field line pattern.
• Floor lift — a Rope Collider floor at Y −0.6 with cables resting on it, then a tall Rectangle attractor above: strands peel off the ground one by one as Strength rises.

• Size X and Size Y are full dimensions (the node halves them internally), so a Size Y of 1.6 spans from −0.8 to +0.8 around Position Y.
• Switching Shape hides the irrelevant ports in the inspector — Radius disappears in Rectangle mode, Size X/Y in Circle mode — but the stored values survive the switch.
• Keep Show on while designing and off in performance: the gizmo draws in the render viewport, not just the editor.
• Attraction stacks: multiple Rope Attract nodes make multi-well fields, and each can be independently animated.
• If cables snap taut against an attractor and jitter, the cure is the Rope's Damping or the system's Quality tier, not a weaker attractor.
• With several Rope Systems open, each draws its own gizmos — the overlay you see belongs to the system that owns the node.