Road Zones and Zone Types

Every road surface in MetaRoad is built from zones. There are two levels:

a Zone Type — a named surface category (Driving, Sidewalk, Tram, Marking, …) defined once for the whole project;
a Road Zone — an instance that assigns a Zone Type to a specific surface (a lane, or a closed-loop fill), with optional per-surface overrides.

Zone Types (project-wide)

A Zone Type defines what a surface is and how it looks when baked. Zone Types are registered project-wide in Project Settings → Plugins → Meta Road → Road Zone Types (UMetaRoadSettings::RoadZoneTypes — a map of name → details).

MetaRoad ships a built-in set — Driving, Sidewalk, Shoulder, Border, Stop, Median, Parking, Biking, Restricted, Marking, Tram, Rail, Bus — and you can add your own.

The built-in Road Zone Types listed in Project Settings

Each Zone Type stores:

Property	Meaning
Mesh Material	Default material applied to this surface when baking
Decal Material	Default decal material — leave empty and no decal is built for this type
Material Priority	Where surfaces overlap, the triangle takes the material with the highest priority
Is Decal	The zone is a flat overlay projected onto the road surface (adds no height) — for asphalt markings such as arrows and stop lines. (Unrelated to Unreal’s `UDecalComponent`.)
Editor Color / Editor Material	Color and preview material used only in the editor (Schematic view)
Description	Free-text note

Zone types shown on a road

Road Zones (per surface)

A Road Zone is a Zone Type in use on a concrete surface. It references a Zone Type and may override that type’s defaults for this one surface:

Property	Meaning
Zone Type	Which Zone Type this surface uses
Override Material	Use a custom material instead of the Zone Type’s default
Override Decal	Use a custom decal material instead of the default
Override Priority	Use a custom material priority instead of the default

Driving and Sidewalk zones

A Road Zone comes in two kinds, matching the two surface families. Both bake all of their zones into a single mesh (with per-zone material IDs).

Driving (FRoadZoneDriving) — a drivable surface: a normal lane, shoulder, bike, bus, or tram lane. It adds one option on top of the shared Road Zone fields:

Property	Meaning
Invert UV0	Flip the U texture coordinate of this lane’s surface

Sidewalk (FRoadZoneSidewalk) — a pedestrian surface with curb generation. Besides the shared Road Zone fields it adds:

Property	Meaning
Default Height	Sidewalk height (cm); can be varied along the lane by the Sidewalk Height attribute
Inside Curb / Outside Curb	Build the curb on the inner / outer edge of the sidewalk
Begin Curb / End Curb (+ cap curves)	Build a cap curb at the start / end of the sidewalk, shaped by a curve
Curb Profile	The Curb Profile asset defining the curb’s cross-section
Override Curb Material	Use a custom curb material instead of the profile’s default

Where Road Zones are used

Per lane — every road lane carries a Road Zone, edited in its Selection panel in Section Mode (the Road Zone / Zone Type rows).
Closed-loop fill — a closed spline fills its outline with a Road Zone via LoopedRoadZone — used for refuge islands, pedestrian crossings, and arrow markings. See Closed Loop Spline.

How the material is resolved

When baking, a surface’s material is chosen in this order:

the Zone Type’s default Mesh Material;
overridden by the Road Zone’s Override Material, if set;
where surfaces overlap, the one with the higher Material Priority wins.

See Baking → Mesh Lane Materials for the baking side.