Terrain Editing

Terrain Editing

Sculpting heightmaps, painting vegetation and water, and generating tiles.

Press E to toggle edit mode. The cursor becomes a brush and a toolbar appears below the nav bar. LMB paints, RMB erases.

Brushes

Cycle with B in edit mode.

Brush	Effect
Raise	Raise (LMB) or lower (RMB)
Flatten	Level the area to the height you first clicked
Paint	Stamp an exact target height
Smooth	Average pixels with their neighbours
Noise	Add fBm procedural noise
Erode	Simulate hydraulic erosion

Flatten samples on first click, so click on the elevation you want before dragging across the area you want levelled.

Brush Controls

Key	Action
[ / ]	Size down / up
Ctrl+Scroll	Size
- / =	Strength down / up
MMB	Eyedropper — sample height or vegetation at the cursor

Height Clamps

Clamps bound what a brush can do, which is how you grade against a fixed elevation without overshooting.

Key	Action
,	Set floor clamp to cursor height
.	Set ceiling clamp to cursor height
Ctrl+,	Clear floor clamp
Ctrl+.	Clear ceiling clamp

Set a floor at rail height and Smooth aggressively around a right-of-way — the clamp stops the brush pulling terrain below the grade.

Vegetation And Water

Press V for vegetation mode, W for water.

In vegetation mode, keys 0–7 select the preset to paint. Water mode paints the water mask — white is water, black is land.

The preset is a vegetation-density level, not a fixed biome:

ID	Density	Approx. mask	Typical use
0	Full	100%	Dense forest and maximum plant placement
1	Very Dense	86%	Woodland or other very dense cover
2	Dense	71%	Trees and brush with small openings
3	Medium	57%	Balanced mixed vegetation and open ground
4	Light	43%	Grass, shrubs, and scattered trees
5	Sparse	29%	Mostly open grass or ground
6	Minimal	14%	Pasture, cropland, and lightly planted yards
7	Clear	0%	Built-up, bare, snow, or open-water ground

Those are placement-mask strengths. The game's vegetation graph can still suppress individual plants around track, water, objects, steep slopes, and cut-tree masks. Generated land-cover data maps source classes onto these levels; it does not store an ecological class in the tile.

The water mask does not draw a visible lake plane. For that, open F9 → Geo → Water in a native FUSE project. The Water workspace can place a rectangular surface with the world pointer, edit every polygon boundary point, reuse the material/profile from a loaded stock lake, and replace a stock lake with an editable FUSE-owned copy. Collider, terrain snapping, UV scale, tessellation, and vertical offset are explicit fields.

RailLoader has no equivalent lake-polygon schema, so these controls are visibly disabled in legacy mode instead of writing data that would be lost on export.

Selection

Press M in edit mode.

Tool	Use
Rect / Lasso	Click and drag to select a region
Wand	Click to flood-fill select similar values

Key	Action
Ctrl+C	Copy
Ctrl+V	Paste — then click to place
Ctrl+X	Cut / export PNG
Delete	Clear the selected region

Copy and paste move terrain between locations, which is the quickest way to repeat a landform.

Tile Generation

Open the Generate panel to build terrain from real-world data.

Action	Result
Click a tile cell	Queue it
Drag across cells	Box-select a region to queue
RMB a cell	Remove from the queue
Scroll	Zoom the grid
MMB drag	Pan the grid
Run	Generate everything queued

Queue the whole area first, then Run once — generation is the slow part.

Tile bounds come from the nearest Map.json: origin.latitude, origin.longitude, and tileDimension. Standalone native projects create this file during the New Mod wizard, so elevation, vegetation, and OSM alignment are not tied to the stock map. Existing legacy tile folders without a manifest use the stock-map defaults for compatibility.

After generation, the editor atomically synchronizes Map.json.tiles with the tile files actually present on disk. Tile cleanup and undo do the same, so a map package cannot silently advertise deleted terrain or omit restored terrain.

Tile Cleanup

A dedicated workspace for trimming large generated blocks down to what a railroad actually needs.

Action	Result
Drag	Mark tiles
Shift+drag	Add to the marked set
Ctrl/right-drag	Keep tiles
Invert / Outside ROW	Mark everything outside the right-of-way

The usual workflow is to mark the ROW, then Invert / Outside ROW, then delete.

Batch deletion asks for confirmation and moves files into a timestamped _TileEditor_Deleted_Tiles recovery folder. Ctrl+Z restores the whole batch — nothing is destroyed immediately.

OSM Guide Overlay

Press O for the OpenStreetMap overlay, which is the practical way to trace real alignments.

The in-game F9 equivalent streams an aligned guide over just the 5×5 or 8×8 game-tile neighbourhood around the camera, following terrain and unloading behind you. It shares the desktop editor's Map.json georeference and caches images under the installed mod rather than a machine-specific path.

Setting	Options
Mode	Clear Lines (default — drops the pale map sheet, keeps features) or Full Map
Resolution	Overview → Ultra, matching z15–z18

Adaptive detail keeps the camera area sharp without rendering the whole coverage window at maximum resolution. Both the desktop OSM toolbar and the F9 Terrain controls show cache usage and offer a confirmation-protected Clear Cache.

OSM and Mapbox data come from third-party services under their own terms — check those before redistributing anything derived from them.

In-Game Terrain Workspace

The F9 Terrain workspace separates practical sculpting from vegetation and water mask painting. The separate Geo → Water workspace creates the visible water surface. Terrain's building-pad, track/road, walkway, grade-plane, ditch, and embankment tools use bounded cut/fill with target convergence, specifically to avoid the spikes a naive flatten produces.

Saving

Ctrl+S saves all modified tiles atomically, keeps up to three recoverable per-tile backups, and clears every derived render cache only after the new file has replaced the old one. Ctrl+X exports the heightmap as a PNG. Press D for diff mode to see exactly which tiles are unsaved — they carry a yellow border.

Related

• Keybinds
• Getting Started
• Track Editing

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Mirrored from docs/TERRAIN_EDITING.md - edit there, not here.