---
title: "3D Terrain"
package: "@phaser-ae/terrain-3d"
tier: Free
version: 3.0.0-4
released: 2026-10-14
updated: 2026-10-19
description: "Shaped ground for outdoor 3D scenes, from a preset landform or your own height function, with editing tools and height, slope and ray queries that match the drawn surface."
url: https://phaser.io/packs/terrain-3d
site: Phaser - https://phaser.io
---

# 3D Terrain

Ground with shape in it for outdoor 3D scenes, plus the questions a game asks of the ground: how high is it here,
which way does it face, how steep is it, and where does this ray hit it. The answers match the mesh you see, so
anything you place sits on it.

## What it does

The landform is data. Name a preset, `hills`, `mountains`, `dunes`, `plateau` or `island`, or pass your own function
from a world point to a height, and nothing else in the pack cares which: a level can come from a seed, a hand-written
function or a file. `featureSize` is in world units, so growing `size` gives you more hills rather than the same hills
made bigger, which is what makes a large terrain feel large. An `after` function reshapes the result on top of a
preset: a continental shelf, a river valley cut through hills, a levelled building site.

What makes it read as ground rather than a coloured surface is the colormap, baked once over the whole terrain. Colour
comes from height bands with soft edges, blends towards each band's cliff colour on slopes, and is jittered at two
scales so flat ground never looks airbrushed, with a fine turf mottle in the grass. Close up, the renderer lays a
world-space grain over sandy ground that fades itself out with distance. The colour is baked, so it costs nothing per
frame.

The mesh is cut into chunks that each cull on their own and join without seams. `heightAt` interpolates over the same
two triangles per quad that the mesh draws, so a tree, a crate or a character placed with it sits exactly on the
surface, and `normalAt` uses the same normals the shading does. With edits, biome masks and footprint checks, the
terrain is an authoring tool as well as a backdrop.

## Features

- **Five landforms or your own** — `hills`, `mountains` with sharp crests, wind-aligned `dunes` with slip faces,
  flat-topped `plateau` and an `island` whose edges go under water, or a `height` function of your own.
- **A baked colormap** — four surfaces (`grass`, `sand`, `snow`, `rock`) or your own colour bands, cliffs drawn on
  slopes, and a `paint` callback for your own ground classes such as beach, dirt or vegetation.
- **Queries that match the render** — `heightAt`, `normalAt`, `slopeAt`, `raycast` and `place`, all of which answer
  exactly headless as well as drawn.
- **Saved edits** — `raise`, `flatten`, `road`, `valley` and seeded `landform` patches, applied in order, with `undo`,
  `redo`, and a JSON-safe `save` and `load`.
- **Biome masks** — feathered `forest`, `lake`, `mountain`, `hills` and `path` regions that tint the ground and that
  `biomeAt` reports to foliage and editor tools.
- **Building footprints** — `foundation` samples a rotated rectangle and returns an upright base height and the
  relief beneath it.
- **Distance detail** — `detail: 'walk'` or `'overview'` coarsens far chunks, with skirts over the gaps and morphed
  transitions, while every query keeps the full-resolution surface.
- **Endless ground** — `wrap: true` makes the terrain a torus that repeats on both axes, so a camera can fly on in one
  direction and never meet an edge.
- **Ground that changes in play** — render a `Heightfield` you own, write its heights, and `refresh` only the region
  that changed.

## Good for

- **Exploration and walking games** — hills or mountains with a first-person character standing on `heightAt`.
- **Driving and vehicle games** — `normalAt` aligns a car or a tank to the slope, and a `road` edit cuts an even route
  through the hills.
- **Strategy games and city builders** — `flatten` pads and `foundation` checks for buildings on uneven ground.
- **God games that reshape the land** — spells that raise a volcano or split an island, through a shared heightfield
  and `refresh`.
- **Flight over endless ground** — a wrapped terrain with no edge, in the style of Magic Carpet.
- **Island and coastal scenes** — the `island` landform with water shoaling against its beaches.
- **Level editors** — edits with undo and redo, saved and loaded as JSON.

## Make it yours

A build takes the size, the grid resolution, the landform, its amplitude, base height, feature size and seed, the
surface or your own colour bands, the colormap resolution, the turf and grain strength and the chunk count.
A procedural world is a seed and a preset; a designed level is a height function or a list of edits on top of one,
kept separately so you can regenerate it. `setDetailTexture` swaps the procedural grain for your own 256×256 image,
blended in three projections so cliffs do not stretch it.

Three quite different terrains from the same pack: a 400-unit grass island with a road and a flattened pad for a
village, walked in first person; a wrapped mountain range, much larger, flown over endlessly with the fog kept inside
half its size; and a strategy map whose own rules write the heights each turn and repaint only the ground that moved.

## A quick look

A mountain range, then a valley, a road and a level building pad cut into it, and a footprint checked:

```ts
game.terrain.build({ shape: 'mountains', size: 800, featureSize: 120, seed: 7 });
game.terrain.edit([
    { kind: 'valley', points: [{ x: 0, z: -80, y: 3 }, { x: 20, z: 80, y: 7 }], width: 15, feather: 20 },
    { kind: 'road', points: [{ x: -30, z: 0, y: 12 }, { x: 30, z: 20, y: 16 }], width: 5, feather: 4 },
    { kind: 'flatten', x: 30, z: 20, radius: 12, value: 16, feather: 3 },
]);
const site = game.terrain.foundation(30, 20, 10, 8);   // an upright base for a 10 × 8 building
const saved = game.terrain.save();                     // JSON-safe, for an editor's save
```

## Works with

- `world-3d` — the 3D world it builds into; `procgen` supplies its noise.
- `rig-fps` — give its floor the terrain's `heightAt` to walk the ground, and its `canMove` check for slope and
  step limits.
- `forest-3d` and `grass-3d` — trees and grass planted on its height, with forests masked by its biomes.
- `water-3d` — seas and lakes that shoal against its beaches.
- `terrain-world-3d` — for landscapes too large to hold in one height array, streamed in tiles.
- `voxels-3d` — for caves, overhangs and ground the player digs through.

## Good to know

- A heightfield has no overhangs, caves or arches; compose rock meshes or `voxels-3d` for those.
- The whole height grid stays in memory with one mesh per chunk; for bounded paging across a very large world, use
  `terrain-world-3d`.
- Edits are an authoring step, not per-frame sculpting, and history keeps up to 32 batches. Ground that changes in
  play goes through `refresh`, which keeps no history.
- `colormapRes` is capped at 2048 and goes into the shared atlas with your other art, and there is no splat-mapped
  material stack beyond the colormap and detail texture.
- A `lake` mask does not dig a basin or make water: flatten or carve one, and compose a water pack.

---

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