Open-world design

Designing a world the player can cross in any order: what counts as an open world and when not to build one, the pillars, landmarks and the triangle rule, density and pacing, traversal, guidance without hand-holding, gating, quests, systemic design, reactive world state, story, the technology (streaming, LOD, floating point, saves, with Godot 4.7 notes), scope, playtesting, common mistakes and a checklist. World structures, Lynch's five elements, weenies, environmental storytelling and lore delivery are on game world design; engine details are on the Godot sheets. Examples from real games cite the developers' own talks or interviews where possible; invented examples are marked.

What "open world" means

An open world is a continuous space the player can approach freely: pick the order, the route and often the goal. Most games sit somewhere between fully linear and fully open.

The table of all structures, with trade-offs, is in world structures.

When not to go open world

Design pillars

Three pillars recur across open-world talks and interviews. Each design decision should serve at least one.

Freedom without discovery is an empty map; discovery without freedom is a museum; emergence without the other two is a toy box. Write the pillars down in one line each and use them to cut features.

Landmarks and sightlines

Players navigate by what they can see. The world's large shapes are its interface.

The triangle rule

At CEDEC 2017, Breath of the Wild director Hidemaro Fujibayashi and terrain lead artist Makoto Yonezu presented the game's field level design, including what the team called the triangle rule: build terrain from triangular shapes (mountains, hills, rock spires).

Gravity and height

The same talk described gravity (引力): places that pull the player in, the way light attracts insects (Fujibayashi's image, as reported by Famitsu). Shrines were made visible from far off, stables offered information, enemy camps held useful weapons, strange rock formations invited a closer look. Height signals importance: the taller a structure, the more it matters.

Weenies, sightlines in towns and Lynch's elements are on game world design.

Density and pacing

Density is time between interesting things, not things per square kilometer. It depends on movement speed, sightlines and what counts as interesting.

Rules:

• Something is always in view. From anywhere, the player should see at least one thing they haven't done.
• Vary the rewards. Loot, lore, a new ability, a shortcut, a view, a story: the same reward everywhere feels like a chore.
• Vary the activities. A map of 200 identical camps is one activity repeated, not 200.
• Leave emptiness deliberately. Quiet stretches create anticipation and make the next find matter.

Checklist fatigue and the map-reveal tower

The tower that reveals a region's map and fills it with icons became known as the "Ubisoft tower", after the Assassin's Creed series popularized it. It solves onboarding but turns the world into a list: the player stops looking at the world and starts clearing icons.

If you keep a reveal mechanic, reveal terrain and names, not every activity, and let the player place their own markers.

Traversal

If moving is fun, the world between points of interest is content; if it isn't, the world is a loading screen.

Fast travel

Most games unlock fast travel after discovery and tie it to a place in the world.

Guidance without hand-holding

Guidance ranges from a UI arrow to nothing at all. Move toward the world end of this scale wherever playtests allow.

Rules:

• Give directions that can be followed in the world. "North of the lake" needs a lake the player can find.
• Record what the player learned. A journal, map notes or a log replaces the marker without losing the player.
• Offer a fallback. An optional marker or hint system keeps less experienced players playing; default it off only if playtests show most players manage.
• Don't let UI replace the world. If players stare at the minimap, the landmarks aren't doing their job.

The "yellow paint" debate and general guidance cues (light, color, leading lines) are on game world design.

Progression and gating

Gates decide what the player can reach when. Soft gates keep freedom; hard gates keep order.

Level scaling vs fixed zones

Skyrim combines the last two: dungeons have a level range, and enemy types stop getting stronger past a plateau (UESP's leveling notes). Whatever the model, make the danger readable before the fight.

Quests and content

Main and side content

Quest templates, made interesting

CD Projekt's Tomaszkiewicz, on Cyberpunk 2077's quests (E3 2019): "We never fail the quest based on choices. We treat those things as outcomes." Consequences keep the quest going instead of resetting it.

Systemic design

At GDC 2017 ("Change and Constant"), Fujibayashi, art director Satoru Takizawa and technical director Takuhiro Dohta described a shift from additive design (each object has one scripted use) to multiplicative design: objects react to the player's actions, and to each other. The team prototyped these rules in a 2D top-down version of the game, burning grass and cutting trees before the 3D world existed.

Dohta called the result a chemistry engine, a "rule-based state calculator", beside the physics engine. As reported from the talk:

Emergent situations need testing tools: spawn anything anywhere, record-and-replay, and a way to set weather and time.

Reactive world state

A world feels alive when it runs without the player and remembers what the player did.

Rules:

• Show the change. A reputation number nobody notices is wasted; guards who mention the fire are not.
• Budget branches. Every persistent change multiplies later content (dialogue, art states, tests).
• Simulate near, fake far. Full simulation near the player; coarse updates (or timestamps) far away.
• Store changes, not the world. Save what differs from the authored start (see save state).

Faction design and reputation systems are on societies and cultures and game world design.

Story in an open world

The urgency problem: the story says "hurry", the structure says "wander". Players either feel guilty exploring or stop believing the story (the ludonarrative dissonance described on game world design).

Writing tips:

• Write each beat to stand alone: who, where, why now.
• Keep a state table of what the player may or may not know at each beat; test the odd orders.
• Let the player's choices echo later, cheaply: a line of dialogue, a changed sign, a new NPC in town.

Technical considerations

A large world has to be streamed in, drawn cheaply at a distance, kept numerically stable far from the origin, and saved without writing everything.

Floating point

A 32-bit float has 24 bits of precision, so the smallest step between values grows with distance from zero. Godot's docs give these as the maximum recommended single-precision ranges (in units, usually meters) before rendering or physics artifacts:

Save state

Give every placed object a stable id in the editor, never an index that changes when a designer adds a crate.

In Godot 4.7

A chunk streamer that keeps a square of chunk scenes around the player loaded:

# chunk_streamer.gd: keeps chunks near the player loaded
extends Node3D
 
const CHUNK_SIZE := 256.0   # meters per chunk side
const RADIUS := 2           # chunks kept in each direction
const PATH := "res://world/chunks/chunk_%d_%d.tscn"
 
@export var player: Node3D
 
var _loaded: Dictionary[Vector2i, Node3D] = {}
var _pending: Dictionary[Vector2i, String] = {}
 
func _process(_delta: float) -> void:
    var wanted := _wanted(_chunk_of(player.global_position))
    for coord in wanted:
        if not (_loaded.has(coord) or _pending.has(coord)):
            _request(coord)
    _poll()
    for coord in _loaded.keys():
        if not wanted.has(coord):
            _loaded[coord].queue_free()
            _loaded.erase(coord)
 
func _chunk_of(pos: Vector3) -> Vector2i:
    return Vector2i(floori(pos.x / CHUNK_SIZE),
        floori(pos.z / CHUNK_SIZE))
 
func _wanted(center: Vector2i) -> Array[Vector2i]:
    var out: Array[Vector2i] = []
    for x in range(-RADIUS, RADIUS + 1):
        for z in range(-RADIUS, RADIUS + 1):
            out.append(center + Vector2i(x, z))
    return out
 
func _request(coord: Vector2i) -> void:
    var path := PATH % [coord.x, coord.y]
    if not ResourceLoader.exists(path):
        return                  # sea or map edge: no chunk
    ResourceLoader.load_threaded_request(path)
    _pending[coord] = path
 
func _poll() -> void:
    for coord in _pending.keys():
        var path: String = _pending[coord]
        match ResourceLoader.load_threaded_get_status(path):
            ResourceLoader.THREAD_LOAD_LOADED:
                _pending.erase(coord)
                var scene: PackedScene = \
                    ResourceLoader.load_threaded_get(path)
                var chunk := scene.instantiate() as Node3D
                chunk.position = Vector3(coord.x, 0.0,
                    coord.y) * CHUNK_SIZE
                add_child(chunk)   # main thread: safe
                _loaded[coord] = chunk
            ResourceLoader.THREAD_LOAD_FAILED, \
            ResourceLoader.THREAD_LOAD_INVALID_RESOURCE:
                _pending.erase(coord)
                push_error("chunk failed: " + path)

Next steps for a real game: unload with a bigger radius than you load (hysteresis) so chunks don't flicker at a border, instance at most one chunk per frame, apply each chunk's save deltas right after instantiate(), and give distant chunks a low-detail stand-in with visibility ranges.

Scope and production

An open world multiplies everything: content, bugs, test time, streaming budgets. Plan for it.

Playtesting and telemetry

Log events with a position, time, and player id: discovered, died, quest_step, fast_travel, map_opened. Plot them over the map image; compare builds.

Common mistakes

Checklist

OPEN-WORLD BRIEF
PILLARS (one line each): freedom / discovery / emergence
CORE LOOP: spot -> travel -> detour -> arrive -> vantage
WHY OPEN? (and why not linear, zones or a hub)
MAP SIZE: minutes to cross on foot / mount / glide
REGIONS:            name, identity, difficulty, landmark
GLOBAL LANDMARKS (visible from most of the map):
DENSITY PER REGION: majors / minors / micros / rests
TRAVERSAL VERBS:    fast travel rule:
GUIDANCE: markers? directions? diegetic cue? journal?
GATES: difficulty / environment / knowledge / ability / story
LEVELING: fixed / ranged / scaled (caps?)
MAIN STORY: urgency answer; beats that work in any order
SIDE CONTENT: handcrafted / templated / systemic mix
SYSTEMS: rules list; what interacts with what
REACTIVITY: schedules, factions, persistence (budget)
TECH: chunk size, load radius, LOD/HLOD, origin, saves
TOOLS: placement, scatter, quest editor, debug teleport
SLICE: which region, what "done" means
TELEMETRY EVENTS: discovered, died, stuck, map_opened
PLAYTEST QUESTIONS: where did you go first, and why?

References

• Hidemaro Fujibayashi, Satoru Takizawa and Takuhiro Dohta, "Change and Constant: Breaking Conventions with The Legend of Zelda: Breath of the Wild" (GDC 2017, GDC Vault) (opens in a new tab): multiplicative design, the chemistry engine
• "Breath of the Wild, science, and clever little lies" (Thumbsticks, 2017) (opens in a new tab): report of Dohta's part of the GDC talk, the chemistry engine's rules
• Zelda Universe, "Zelda Team discusses Breath of the Wild's development and 2D Zelda prototype at GDC" (2017) (opens in a new tab): the 2D prototype
• CEDEC 2017 session: "Field Level Design in The Legend of Zelda: Breath of the Wild" (Japanese) (opens in a new tab): speakers Hidemaro Fujibayashi and Makoto Yonezu
• Famitsu report of the CEDEC 2017 field design talk (Japanese, 2017) (opens in a new tab): gravity, the triangle rule, playtest heatmaps
• Robert Yang, "Open world level design: spatial composition and flow in Breath of the Wild" (Radiator Blog, 2017) (opens in a new tab): English summary and critique of the CEDEC talk, three scales of triangle
• Nintendo Life, "Zelda: Breath of the Wild's Ingenious Design Is All About Triangles, Apparently" (2017) (opens in a new tab): height as importance, towers and heatmaps
• Tim Turi, "An interview with FromSoftware's Hidetaka Miyazaki" (PlayStation Blog, 2022) (opens in a new tab): freedom in Elden Ring, Torrent and Sekiro's traversal, coming back later
• Alex Beachum and Loan Verneau, "Curiosity-Driven Exploration: The Design of Outer Wilds" (GDC 2020 announcement, Game Developer) (opens in a new tab)
• Kelsey Beachum, "Sparking Curiosity-Driven Exploration Through Narrative in Outer Wilds" (GDC 2021, GDC Vault) (opens in a new tab)
• "Live, die, repeat: How Outer Wilds piques curiosity in an ambivalent solar system" (Game Developer) (opens in a new tab): knowledge as the only progression, "Everything is on its own clock"
• Bill Rockenbeck, "Blowing from the West: Simulating Wind in Ghost of Tsushima" (GDC 2021, GDC Vault) (opens in a new tab) and Game Developer's summary (opens in a new tab): the Guiding Wind instead of a map marker
• MCV/DEVELOP, "The Witcher 3 quest designers talk balancing story with gameplay and declaring war on 'fetch quests'" (2016) (opens in a new tab): Mateusz Tomaszkiewicz and Pawel Sasko
• Game Developer, "From The Witcher 3 to Cyberpunk: the evolution of CD Projekt's quest design" (2019) (opens in a new tab): choices as outcomes, not failures
• UESP, Skyrim: Radiant (opens in a new tab) and Skyrim: Leveling (opens in a new tab): radiant quests; dungeon level ranges and enemy plateaus
• The Elder Scrolls IV: Oblivion (Wikipedia) (opens in a new tab): level scaling and its criticism
• Radiant AI (Wikipedia) (opens in a new tab): NPC schedules and the Radiant system in Oblivion and Skyrim
• Open world (Wikipedia) (opens in a new tab): definition, map-reveal towers ("Ubisoft towers"), emergent gameplay
• Far Cry 5 (Wikipedia) (opens in a new tab): towers removed, the Resistance meter, Dan Hay's "anecdote factory"
• Clive Thompson, "Halo 3: How Microsoft Labs Invented a New Science of Play" (Wired, 2007; republished by ABC News) (opens in a new tab): playtest tracking of where players died
• Floating origin (Wikipedia) (opens in a new tab): origin shifting for large worlds
• Godot docs: Large world coordinates (opens in a new tab): precision ranges, double-precision builds, limitations
• Godot docs: Background loading (opens in a new tab) and Thread-safe APIs (opens in a new tab)
• Godot docs: Visibility ranges (HLOD) (opens in a new tab), Mesh level of detail (opens in a new tab) and Occlusion culling (opens in a new tab)
• Terrain3D (Godot Asset Library) (opens in a new tab): a GDExtension terrain add-on