How does terrain work in video games?

A beginner’s guide to video game terrain: how tiles, heightmaps, voxels, and noise create the ground players walk on, and how to design terrain that’s fun to explore.

Rolling hills, jagged mountains, sandy beaches, winding rivers. When you explore a game world, the ground under your feet does a lot of quiet work. It sets the mood, shapes where you can go, and decides what you see on the horizon. But what is that ground actually made of?

This guide explains how game terrain works, from tile-based 2D maps to 3D landscapes, in plain language. You’ll learn the main techniques game makers use, how terrain gets its look, how worlds can be generated automatically, and how to design terrain that’s fun to move through.

What is terrain in video games?

Video game terrain is the ground surface of a game world. That means it’s the main surface that players and other moving objects travel across, and the base that everything else sits on. It usually imitates natural surfaces like rock, sand, gravel, and soil, but it can also stand in for human-made ground like cracked pavement or overgrown paving stones.

Terrain isn’t just scenery. Shaping the land is a design tool. One level design reference defines landscape design in games as the purposeful shaping of the land to support how players move and what you want them to experience.

Terrain in 2D games: tiles

Many 2D games build their worlds out of tiles: small, regular images that fit together like a grid to form the whole level. A single grass tile, a dirt tile, and a water tile can be reused over and over to build a large map. Tiles can define how a world looks, how it works – which squares are walkable, which are walls – or both.

Tiles are a natural fit for top-down and side-view games, and for anyone who wants to build levels quickly from a small set of reusable pieces.

Terrain in 3D games: heightmaps

Most 3D terrain starts with a heightmap. A heightmap is a grayscale image where each pixel’s brightness represents height: white is high, black is low, and gray is somewhere in between. The game takes a flat grid and raises or lowers each point based on the matching pixel, turning a flat sheet into hills and valleys.

Heightmaps are efficient and easy to edit, which is why they’re so common. But they have one big limitation: each point on the map can only have one height. That means a heightmap can’t represent caves, tunnels, or overhangs – anything where ground sits above other ground.

Beyond heightmaps: voxels

For worlds that need caves or terrain that can be dug and destroyed, some games use voxels instead. A voxel system treats the world as a 3D grid of tiny cells, each either solid or empty. This makes caves, overhangs, floating islands, and fully destructible ground possible. Historically, the trade-off has been complexity: voxel terrain is harder to build and run, so it’s usually used only when those abilities are essential to the game. However, this is starting to change, as AI tools like Unity Spark begin to make these approaches more accessible.

How terrain gets its look

Shape is only half the story. Terrain also needs surfaces: grass on the plains, rock on the cliffs, sand by the water.

A common technique is the splatmap: a hidden texture that tells the game which surface to show where, and how to blend between them. A splatmap often has four color channels, each assigned to a different material – for example, grass, soil, rock, and sand. Where the grass channel is strong, you see grass. Where two channels overlap, the surfaces blend smoothly instead of switching abruptly.

Surfaces don’t always have to be painted by hand. Many tools apply materials automatically using rules based on the terrain itself – for example, putting rock on steep slopes. Some go further and decorate whole regions automatically with themed sets of plants, rocks, and textures, often called biomes.

Generating terrain automatically

Some games create their terrain with code instead of by hand. This is called procedural generation, and one of the most common starting points is noise.

Noise, in this sense, is a mathematical pattern of smooth, random-looking values. Treat those values as heights and you get a heightmap of gentle hills. Layering several versions of the noise at different scales – big hills plus smaller bumps – produces more natural, rugged terrain. From there, you can turn the lowest areas into water, and combine height with a second noise pattern for moisture to decide where forests, deserts, and snow appear.

Because each point can be calculated on its own, this approach can even generate worlds that seem to go on forever, creating each area only when the player gets close.

Noise has limits, though. Different areas don’t relate to each other, so the map can start to feel samey, and it usually takes a lot of tweaking to get results you like. It’s a great, quick starting point for small projects and game jams, which many creators later replace with something more tailored to their game.

Designing terrain that’s fun to explore

Good terrain isn’t just realistic. It supports how players move. A few principles from level design help:

Plan the big picture first.

Start with a simple map that labels the main areas and how they connect. Then shape rough hills, valleys, and paths before adding any detail. Resist the urge to sculpt fine details early.

Decide on scale early.

How far apart should places be? How steep can a slope be before it’s too steep to climb? Work this out early, because most terrain tools make it hard to move or resize big landforms later. Moving a mountain is harder than moving a wall.

Make it readable.

Players should be able to tell where they can and can’t go. Watch out for slopes that look climbable but aren’t, and spots where players can get stuck. Leave generous flat space at the top and bottom of ramps so players don’t overshoot and fall.

Borrow from nature.

Water flows downhill and curves around obstacles, so rivers – and the valleys around them – tend to curve. People follow the land, so paths usually curve around hills and trees too. Trees work like walls you can walk through, enclosing spaces without fully blocking them.

Test it by playing it.

Walk through your terrain often. Look for areas that feel too big, routes that feel too long, and places where players can get stuck or fall into a gap.

Header image note: Glowing wireframe landscape that shifts from blue in the low areas to orange on the peaks. Image generated by Claude Opus 5.5, October 7, 2026.