spline

Reusable spline library for rails, paths, procedural placement, and debug drawing. Aggregates the core, placement, and drawing sub-modules into a single namespace so callers only need one require.

Supports:

• linear, Catmull-Rom, and Bezier curves
• eased traversal modes (linear, easeInQuad, easeOutSine, easeInOutCubic, etc.)
• sampling by count or by spacing
• placement helpers for repeated items (fence posts, distributed instances)
• runtime constraint of an entity to a spline progress value
• lightweight debug drawing using spawned markers and segment meshes

Exports

Curve construction (forwarded from spline.core):

• M.new(points, opts) / M.linear(points, opts) / M.catmullRom(points, opts) / M.bezier(points, opts)

Sampling and queries (forwarded from spline.core):

• M.evaluate(path, t) / M.evaluateEased(path, t, easing)
• M.tangent(path, t) / M.length(path, steps?)
• M.sample(path, count, opts?) / M.sampleBySpacing(path, spacing, opts?)
• M.closestProgress(path, point, steps?) / M.resolveEasing(easing) / M.easingNames()
• M.measure(pathOrPoints, opts?) / M.atDistance(measured, distance, wrap?): the curve by arc length, read at constant speed

Placement helpers (forwarded from spline.placement):

• M.distribute(path, count, opts?) / M.distributeBySpacing(path, spacing, opts?)
• M.fence(path, spacing, opts?) / M.constrain(entityId, path, progress, opts?)

Debug drawing (forwarded from spline.drawing):

• M.draw(path, opts?) / M.drawMarkers(path, opts?) / M.drawSegments(path, opts?) / M.clearDrawn(ids)

Sub-module handles:

• M.placement: table — the raw spline.placement table.
• M.drawing: table — the raw spline.drawing table.

Usage

local spline = require("@builtin::modules.spline")

local path = spline.new({
    { x = -6, y = 0, z = 0 },
    { x = -2, y = 2, z = 4 },
    { x = 2, y = 2, z = -4 },
    { x = 6, y = 0, z = 0 },
}, { mode = "catmullRom" })

local pos = spline.evaluateEased(path, 0.35, "easeInOutSine")
local posts = spline.fence(path, 1.5, { lateralOffset = 0.6 })

Notes

• To move an entity along a spline at a constant speed, add the PathFollower component and call follow(path) with the spline.
• For networks of paths (roads, tracks, rails, lanes, routes) with junctions, drivable surfaces, terrain conformance and route queries, use @builtin::modules.pathNetwork.
• See the sub-module READMEs for full signatures: spline.module/core.module, spline.module/placement.module, spline.module/drawing.module.