beamng-road-layers

name	beamng-road-layers
description	Reference for BeamNG road spline layer system - how visual layers (markings, edge blends, wear patterns) map to DecalRoad objects with lateral positioning, materials, and widths. Use when generating or configuring road visual layers.
user-invocable	false

BeamNG Road Spline Layer System

Overview

A road spline in BeamNG consists of a centerline with widths, plus multiple layers that each generate one or more DecalRoad objects. Each layer represents a visual element (marking, blend, wear pattern) positioned relative to the road centerline.

Layer Properties

Property	Type	Default	Description
material	string	"road_invisible"	Material name for the DecalRoad
width	float	10.0	Fixed width in meters (used when isTrackWidth = false)
position	float	0.0	Lateral position: -1.0 = left edge, 0.0 = center, +1.0 = right edge
isTrackWidth	bool	true	If true, width follows road width; if false, uses fixed width
isFlip	bool	false	Reverse the spline direction (used for bilateral asymmetric layers)
texLen	float	10.0	Texture repetition length along spline in meters
fadeIn	float	1.0	Fade-in distance at road start (meters)
fadeOut	float	1.0	Fade-out distance at road end (meters)
renderPriority	int	10	Draw order (higher renders on top)
isOverObjects	bool	false	Render above other scene objects

Lateral Offset Calculation

The position value determines where a layer sits relative to the road centerline:

offsetPoint = centerPoint + binormal * position * 0.5 * roadWidth

Where:

• centerPoint = interpolated position on the road centerline
• binormal = perpendicular vector to the road direction (pointing right)
• position = lateral position value (-1.0 to +1.0)
• roadWidth = road width at that point

Examples:

• position = 0.0 → centered on road
• position = -1.0 → left edge of road
• position = +1.0 → right edge of road
• position = ±1.1 → slightly beyond road edge (for edge blends)

Layer-to-DecalRoad Mapping

Each layer creates one DecalRoad (or multiple if >100 nodes). The DecalRoad receives:

• Nodes with laterally-offset positions and appropriate widths
• Material, textureLength, renderPriority from the layer
• improvedSpline = true, drivability = -1.0 (always)
• startEndFade from fadeIn/fadeOut values

Auto-Generated Layer Types

BeamNG's road spline editor supports auto-generated layers organized into categories. See layer-reference.md for complete details on all layer types with exact materials, widths, and positions.

Summary of Layer Categories

Category	Material	Width	Position	Description
Edge Lines	m_line_white	0.25m	±1.0	Solid white edge markings
Center Line	m_line_white_discontinue	0.2m	0.0	Dashed center marking
Lane Lines	m_line_white_discontinue	0.2m	per-lane	Dashed lane dividers
Edge Blend 1	m_road_asphalt_edge	1.0m	±1.1	Close asphalt-edge transition
Edge Blend 2	m_road_edge_dirt	2.0m	±1.25	Mid-range dirt transition
Edge Blend 3	m_road_asphalt_edge_grass	3.0m	±1.35	Far grass transition
Light Tread	m_tread_marks_clean	track	per-lane	Light tire marks
Heavy Tread	road_rubber_double	track	per-lane	Heavy tire marks
Road Cracks	m_asphalt_cracks_02	track	per-lane	Crack overlay
Repair 1	repair1	track	per-lane	Repair patches
Repair 2	repair2	track	per-lane	Repair patches
Patches	road_patches1	track	per-lane	Road patches
Damage 1	m_asphalt_damaged_01	track	per-lane	Damage texture
Damage 2	m_asphalt_damaged_02	track	per-lane	Damage texture

"track" width means isTrackWidth = true (follows road width).

Render Priority Stacking

Layers render bottom-to-top by renderPriority:

1. Edge blends (priority 9) - below everything
2. Road surface/wear layers (priority 10) - standard
3. Road markings (priority 10+) - on top

Bilateral Layers

Many layer types come in left/right pairs:

• Edge Lines: Left (position -1.0) + Right (position +1.0)
• Edge Blends: Left + Right (right side uses isFlip = true)
• Lane layers: Created per-lane with calculated positions

The isFlip flag on right-side edge blends ensures the texture direction matches the road direction from that side's perspective.