Baking (Mesh Generation)

Baking converts the road layout data stored in your URoadSplineComponents into actual 3D assets placed in the level: static meshes for the drive surface, sidewalks and curbs; spline meshes for road markings; and decals for surface overlays.

Baking is an action of the Meta Road editor mode, not a separate tool. Open the mode, select the Bake tile in the Bake palette, and run Bake Selected or Bake All (see The Meta Road Editor Mode).

Tip

Preview before you bake. While editing you can switch the view toggle to Preview for a live, non-destructive preview of exactly what will be generated — nothing is written to disk until you bake.

Running a bake

1. Enter the Meta Road editor mode and open the Bake palette; click the Bake tile.

2. Select the road actor(s) you want to build.

3. Click Bake Selected (the selected AMetaRoad actors) or Bake All (every road actor in the level).

4. The bake runs in the background with a progress notification (with per-actor OK / warning / error counts and an Open Log button). When it finishes, a generated actor named <YourActor>_Gen is created, or the mesh is written in place, depending on the generated-asset settings.

For example, baking the actor RoadActor11 produces RoadActor11_Gen:

The generated actor holds the mesh components (usually UStaticMeshComponent and USplineMeshComponent) referencing the generated assets:

Clear (on the same tile) removes the generated _Gen actors/assets without generating new ones.

Each bake generates assets for these layers:

• Drive Surface + Decals

• Sidewalks

• Curbs

• Marks

• Spline Meshes (road attributes such as guardrails)

Where the settings live

• Per-actor build settings (UMetaRoadBuildSettings) — which layers to build, their materials, and triangulation parameters. Edit them per road in the Preset sub-mode (with a live preview) or in the actor’s Details. Baking always uses each actor’s committed build settings.

• Generated-asset settings (UMetaRoadBakeSettings) — where the assets are written and how (see below), edited in the Bake panel.

Generated-asset settings

The Bake panel exposes a Generated Assets category (backed by UMetaRoadBakeSettings) that controls where generated mesh assets are written, how they are saved, and what happens to the previous bake’s assets when you re-bake. These settings live in your per-project editor preferences — a single shared instance, not stored per road and not saved in the level — so they apply to every bake until you change them.

Where assets are saved — output location

Generation Location chooses the root folder generated assets go into:

Option	Where the assets land
World Relative (default)	A folder next to the current level (the level’s own content folder) — keeps a level’s generated meshes together with the level.
Global	The top-level /Game content folder.
Current Asset Browser Path	The folder currently selected in the Content Browser (falls back to World Relative if none is available).

Under that root, several options shape the exact path. They are all ignored when Current Asset Browser Path is used (it writes straight into the selected folder):

Option	Default	Effect
Auto Generated Asset Path	_GENERATED	Sub-folder segment appended under the root. Leave it empty to write directly into the root.
Use Per User Autogen Subfolder	on	Adds a per-user sub-folder under the auto-generated path, so several people baking the same level don’t overwrite each other.
Autogen Subfolder User Name Override	(OS user name)	Custom name for that per-user sub-folder.
Store Unsaved Level Assets In Top Level Game Folder	on	(World Relative only) For an unsaved level — whose content folder can’t be resolved — write into /Game instead of the transient /Temp.
Append Random String To Name	on	Appends a short random suffix to each asset name so bakes never collide.

With the defaults, baking saves meshes to something like …/<Level>/_GENERATED/<YourName>/RoadActor11_… _ab12cd.

How assets are saved — save behavior

Generation Mode decides what happens to each asset the moment it is created:

Option	Behavior
Auto Generate And Autosave	Create the asset and immediately save it to disk.
Auto Generate But Do Not Autosave (default)	Create the asset and mark it dirty — it appears in the Content Browser, but you save it yourself (Ctrl+S / Save All).
Interactive Prompt To Save	Ask for a target folder via a save dialog. To avoid one dialog per sub-mesh, MetaRoad prompts once per bake and reuses that folder for the whole batch; cancelling aborts the bake (nothing is generated).

Auto-cleaning previous assets

Each road actor has a Replace on Regenerate flag (AMetaRoad, default on). When it is on, re-baking that actor first removes the previous bake’s _Gen actor and its generated mesh assets, then builds fresh ones — so re-baking doesn’t leave orphaned meshes behind. With it off, a re-bake keeps the old output in place next to the new one. The Clear action runs the same cleanup for the selected actors unconditionally (ignoring the flag) without generating anything.

How the old mesh assets are disposed is set by Clean Strategy:

Option	What it does	Undo (Ctrl+Z)
Permanent Delete (default)	Permanently deletes the previous bake’s mesh assets from disk.	Still restores the old _Gen actor, but its mesh references become empty, and undo history from before the bake is cleared.
Move To Trash	Moves (renames) the old mesh assets into a _Trash sub-folder next to them instead of deleting — names are made unique so repeated bakes don’t collide.	Fully reversible: restores the old actor with valid mesh references, nothing is lost from disk, and prior undo history is preserved.

Note

Use Move To Trash while iterating (safe and fully undoable) and Permanent Delete for clean final output. The _Trash folder is not emptied automatically — delete it yourself once you’re happy with the result.

Spline grouping (important)

Baking forms generation units from your splines: one unit per (AMetaRoad actor, SubGroup). Splines in the same actor and the same SubGroup are triangulated into one seamless mesh; different sub-groups/actors are generated independently. Keep an intersection’s splines in one actor and SubGroup, and split large networks so each junction is its own unit. This rule is explained in full — with examples — in The MetaRoad Workflow → Spline grouping.

Mesh Lane Materials

All road lanes have a Lane Type:

You can add new Lane Types in Project Settings. Each Lane Type has a Default Material:

For a selected road lane you can override the default lane material:

You can also override the Lane Type material from the road’s build settings:

So the road-lane material is resolved in this priority order:

1. Default material from the Lane Type description

2. Override material from the road’s build settings

3. Override material from the selected road-lane menu

Mesh UVs

Road-surface generation produces two texture-coordinate channels:

• UV0 — a separate track per lane. Useful for road ruts or tram tracks.

• UV1 — a track for the left and right sides of the road. Useful for road patches.

To display the debugging materials shown above, choose the UV0 Debug or UV1 Debug preset:

Mesh Vertex Color

For road-surface materials we recommend using the Vertex Color attribute to control where textures on the UV0/UV1 channels appear (puddles, ruts, patches). This removes artifacts at seams where several URoadSplineComponents meet:

Suggested parameters for the Drive Surface vertex color:

They set the vertex color at the center and edges of the mesh, and where lanes intersect:

For complex intersections you may still need to paint vertices manually in Mesh Paint mode.

See also

• FBX Export — export the road meshes to .fbx files.

• Preset Mode — stage build settings against the live preview.