Climbable Ropes for Create Aeronautics

NeoForge addon for Create: Aeronautics, specifically the bundled Simulated physics module that handles ropes. Adds two empty-hand climb modes alongside Simulated's existing wrench-driven zipline system: hanging rope strands (vertical by default; the angle gate is configurable up to fully horizontal), and plunger-fired ropes between paired LaunchedPlungerEntity projectiles.

How it works

Simulated already has a rope-strand riding system (ZiplineClientManager) that lets the player slide along a rope held by Create's wrench-tagged item. That system is left completely untouched (no mixins, no overrides), so ziplines behave exactly as in vanilla Simulated.

This mod adds two separate climb modes driven by empty-hand interaction.

Hanging rope strands

• The player right-clicks a rope strand with an empty main hand.
• A ClientTickEvent.Post handler (ClimbController) raycasts against rope strands using Simulated's own ZiplineClientManager.raycastRope helper.
• If a strand within reach is hit and the segment is within maxClimbAngleFromVertical of vertical (default ~32°, configurable up to 90° for fully horizontal ropes), we record the rope UUID, send Simulated's RopeRidingPacket so the server treats the player as riding (no fall damage, hanging animation, etc.), and run per-tick physics.
• Climb motion follows the local rope tangent rather than pure Y, with arc-length-based top/bottom limits and a 3D snap-pull, so diagonal and horizontal climbs feel natural.
• Forward direction (W) is locked at embark: vertical-ish ropes use the higher-Y endpoint; for shallower ropes the player's look direction wins, so W follows how the player attached, not how the rope was placed.
• W climbs up, S descends, sprint + S slides faster (smooth acceleration up, smooth coast back down). On near-horizontal ropes, slide acceleration scales with |tangent.y|, so a flat rope just travels at descend speed.

Plunger ropes

• Two paired LaunchedPlungerEntity projectiles (fired from Simulated's Plunger Launcher) form a rope between them.
• PlungerClimbController iterates ClientLevel.entitiesForRendering() for plungers, computes endpoint positions in world render space (accounting for Sable sublevel transforms so ropes attached to assembled physics objects work), and ray-segment-tests against each pair.
• Embark direction is locked when grabbing the rope. For vertical-ish ropes W goes to the upper end; otherwise W goes toward whichever end the player is facing.
• Slide acceleration and terminal speed scale with sin(angle from horizontal), so vertical plunger ropes accelerate fastest and near-horizontal ropes don't slide beyond the descend baseline.
• The same RopeRidingPacket signal drives the hanging animation in multiplayer.

Plunger ziplines

• Right-clicking a plunger rope while holding a CHAIN_RIDEABLE-tagged item (typically Create's wrench) embarks the player as a zipline rider rather than a climber.
• PlungerZiplineController mirrors Simulated's ZiplineClientManager.ridingTick physics: per-tick damping (v * -0.6, with the along-rope component subtracted), assistance (dir * v.dot(dir) * 0.04), and a spring force pulling the player anchor toward the closest point on the segment. Gravity and normal WASD motion come from vanilla player physics, so a horizontal plunger rope can be walked across as a temporary bridge.
• No steepness gate: plunger ropes are taut straight lines, so any angle is rideable (unlike the strand zipline which gates by maxRopeZiplineAngle).
• Dismount on Sneak, fly toggle, more than 5 ticks grounded, plunger removed/unplunged, or pushed past either endpoint with velocity.dot(dir) > 0.6.

Building

This depends on Simulated's compiled jar. Either:

• Build Simulated locally first (gradlew :simulated:neoforge:build in Simulated-Project/), or
• Drop a built simulated-neoforge-*.jar into ./libs/.

Then run gradlew build.

Controls

To grab on: look at a near-vertical rope strand or a plunger rope within block-interaction range, with an empty main hand, and right-click.

While climbing:

Input	Action
Forward (W)	Climb up (or along the rope toward the locked forward end on plunger ropes)
Back (S)	Descend
Sprint + Back	Slide: accelerates from descend speed up to a sustained slide, coasts to a stop on release
Sneak (Left Shift)	Dismount (let go, no impulse)
Jump (Space)	Jump off with a vanilla-jump-strength upward impulse. When you're at the top of the rope and a block is above, jump instead mantles you onto that block.
Stand on the ground without pressing forward	Auto-dismount after a few ticks
Mouse / camera	Rotates the player around the rope; you hang on the side you're facing
Toggle creative flight	Dismount
Switch off empty hand	Dismount

Sneak-to-dismount matches Simulated's existing on-embark hint ("Press [LEFT SHIFT] to dismount").

Embarking the existing Simulated zipline mode still works the same: look at the rope while holding a CHAIN_RIDEABLE-tagged item (typically Create's wrench) and right-click.

Ziplining a plunger rope

Hold a CHAIN_RIDEABLE-tagged item (typically Create's wrench), look at a plunger rope within block-interaction range, and right-click. You'll latch on and slide under gravity + your own input. Sneak to dismount, or run off either endpoint with enough forward momentum.

Configuration

Server-side config lives at <world>/serverconfig/climbable_ropes-server.toml, generated on first world load. On a dedicated server the operator owns it; in singleplayer the player owns it (per world). Values auto-sync to connected clients on join, so the server is authoritative. Clients can't tweak the file locally to climb faster.

The tables below are the quick reference. For a full guide with units, in-game behavior, interactions between settings, and tuning recipes, see CONFIGURATION.md.

[climbing]

Key	Default	Description
climbSpeed	0.18	Speed along the rope when holding forward (blocks/tick).
descendSpeed	0.22	Speed along the rope when holding back (blocks/tick).
jumpOffVelocity	0.42	Upward impulse applied when jumping off.
maxClimbAngleFromVertical	90.0	Maximum angle from vertical (degrees) at which a hanging-rope segment can be grabbed. The default allows any angle, including horizontal. Lower toward 0 to require near-vertical ropes (e.g. 31.79 matches the legacy 0.85 dot-product threshold).

[sliding]

Key	Default	Description
slideSpeed	1.2	Maximum sprint-descend slide speed.
slideAcceleration	0.05	How quickly the slide ramps up.
slideDeceleration	0.04	How quickly the slide eases out after releasing back.

[features]

Key	Default	Description
allowVerticalRopeClimbing	true	Toggle hanging-rope climb.
allowPlungerClimbing	true	Toggle plunger-line climb.
allowPlungerZipline	true	Toggle ziplining along plunger ropes with a CHAIN_RIDEABLE-tagged item.
allowBlockMantle	true	When jumping off at the top end of a rope, mantle onto the block above instead of getting a normal upward impulse.

Toggling a feature off only blocks new embarkations; in-progress climbs finish normally.

[advanced]

Key	Default	Description
snapPull	0.55	How aggressively the spring drags you toward the rope each tick.
snapVelocityCap	0.35	Maximum per-tick velocity the snap spring can contribute.
maxLeashDistance	3.0	Distance from the rope (blocks) at which external forces dismount you.
bottomDismountOffset	0.6	How close to the lower endpoint counts as "at the bottom" for the grounded auto-dismount.
bottomGroundedDismountTicks	5	Ticks of ground contact at the bottom before auto-dismount.
ropeHoverRadius	0.25	Raycast hitbox radius (blocks) for rope hover detection. Larger values make ropes easier to aim at.

Defaults preserve the standard behavior; these affect physics feel and targeting, so change them with care.