trackBuilder/meshes - Cross-Section Mesh Definitions

Reference for extensions/util/trackBuilder/meshes.lua. Defines cross-section profiles (tubes and side walls) used by the track builder's procedural mesh system.

Exports (returned table)

This module returns a plain table (not M), so it's used via require() not as an extension.

Internals

createTube(radius, steps, wallHeight)

Generates a tube cross-section with inner and outer shell. Uses trigonometric sampling around a semicircle or full circle. Includes optional vertical wall extension above the tube opening. Returns {crossPoints, uv, cap, material, flipUVRight}.

createSideWall(height, angle)

Creates a simple triangular wall profile. The angle parameter tilts the wall inward. Returns the same cross-section format with sharp edges flagged.

How It Works

Each mesh definition is a cross-section profile containing:

• crossPoints: vec3 positions defining the 2D cross-section shape
• uv: Per-point UV channel (0 for outer surface, 1 for inner)
• cap: Triangle face indices for end caps
• material: Always "track_editor_border"
• sharp: Indices where normals should not be smoothed (walls only)
• flipUVRight: UV orientation flag

The track builder extrudes these profiles along spline paths to create the 3D track geometry.

local meshes = require('util/trackBuilder/meshes')
local tube = meshes.tube5m
-- tube.crossPoints contains vec3 positions for the cross-section
-- Used by segmentToProceduralMesh to generate the final 3D mesh