Coastlines & coastal features
Two Build-tool knobs control how the coastline is drawn: Coastline fidelity and the Coastal features toggle.
Coastline fidelity
Section titled “Coastline fidelity”A 0–1 slider in the Coastlines card of the Build tool. Controls how closely the coastline stroke hugs the actual shoreline.
The renderer maps the slider to Chaikin smoothing iterations:
| Slider | Smoothing |
|---|---|
| 0.00–0.16 | 3 passes (very smooth, drifts away from the mesh) |
| 0.17–0.49 | 2 passes |
| 0.50–0.82 | 1 pass |
| 0.83–1.00 | 0 passes (raw polyline, every vertex is a jog) |
Default 0.6 — tighter than the legacy three-pass default while still readable on sketchy styles.
Coastal features
Section titled “Coastal features”A toggle in the Land section. When on, the renderer classifies each coastline segment and draws each category differently.
The four kinds:
- Default — open ocean coast, neutral land. Standard medium stroke.
- Cliff — inland terrain is mountain / snow biome, or the slope rises sharply. Heavier dark stroke, full opacity.
- Beach — inland terrain is grassland / desert / rainforest / beach biome with a shallow inland slope. Light dotted stroke, half opacity.
- Cove — the polyline curves sharply inward (a bay or inlet). Even heavier stroke than default, slightly lower opacity for an inset feel.
Cove takes precedence over cliff and beach, so a sharply-curved bay reads as a bay regardless of the inland terrain behind it.
Classification rules
Section titled “Classification rules”Internally, the classifier samples a point about six map cells inland of each coastline segment and looks at the triangle there:
- Mountain or snow biome (or steep slope) → cliff.
- Beach / coast / grassland / desert / rainforest biome → beach.
- Anything else, or a degenerate sample → default.
Cove is overlaid on top by inspecting the polyline’s local turning angle: runs of two or more consecutive points where the included angle is under 130° become coves.
When to turn it off
Section titled “When to turn it off”The classifier adds one mesh pass at render time. Turning it off:
- Speeds up the live preview noticeably at high mesh detail.
- Restores the legacy single-stroke coast look.
If you want the same unified stroke colour everywhere but want to keep the slider’s fidelity behaviour, leave Coastal features off and tune fidelity directly.
Related
Section titled “Related”- Terrain & detail — the parent section.
- Custom palette — the Coast / border ink override changes the colour of the default and cove strokes (cliff uses a darker version of the same ink automatically).
- Kingdoms — kingdom borders along the coast are suppressed in favour of the coastline stroke, so this layer is effectively the only one drawing along the sea.