Biome Spawn Director

Biome Spawn Director lets Forge modpack authors control where a world begins using biome selectors and real geographic constraints instead of fixed coordinates.

Use it for starts such as:

• spawn somewhere in a specific biome or biome tag;
• begin deep inside a biome instead of on its edge;
• begin a controlled distance from a shoreline;
• start underwater or on the seabed with a minimum water depth;
• require another biome to exist within a chosen distance band;
• avoid selected biomes or nearby structures;
• give every new player their own directed start instead of sharing one world spawn.

Features

• Exact biome IDs and #biome_tag selectors
• WORLD mode for one shared authored world origin
• PER_PLAYER mode for independent first-join placement
• Placement modes: SURFACE, UNDERWATER, SEABED, CAVE
• Minimum / maximum biome-interior distance
• Minimum / maximum dry-shore distance
• Required neighboring biome with distance bounds
• Minimum / maximum water-column depth
• Final Y-range constraints
• Biome and structure exclusions
• Strict vanilla fallback or optional relaxed-constraint fallback
• Persistent WORLD spawn selection
• Existing-player protection when adding the mod to an established world
• Optional Water Breathing arrival grace for aquatic starts
• Admin preview, placement, reset, and status commands
• Search diagnostics for rejected candidates
• Singleplayer loading-screen status while a WORLD origin is being resolved

Requirements

• Minecraft 1.20.1
• Forge 47.4.10 or newer
• Java 17

Biome Spawn Director's spawn logic is server-authoritative. On a dedicated server, the server owns placement. In singleplayer, include the mod normally in the client/modpack so the integrated server can resolve the origin; the client copy also provides the Locating origin... loading-screen status.

Configuration

After first launch, edit:

config/biomespawndirector-common.toml

The mod is disabled by default so simply adding the JAR to an existing pack will not move players until the pack author opts in.

Simple biome start

[general]
enabled = true
mode = "WORLD"
placement = "SURFACE"

[biomes]
targets = "minecraft:plains"

Ocean start with reachable shore

[general]
enabled = true
mode = "WORLD"
placement = "UNDERWATER"
fallback = "VANILLA"
arrivalWaterBreathingSeconds = 30

[biomes]
targets = "#minecraft:is_ocean"
searchAnchors = "#minecraft:is_ocean"
excluded = "minecraft:frozen_ocean,minecraft:deep_frozen_ocean"

[relativePosition]
minShoreDistance = 48
maxShoreDistance = 176
minWaterDepth = 8
underwaterDepthBelowSurface = 6

WORLD mode resolves and persists one shared origin. On a new singleplayer world, Biome Spawn Director resolves that origin before the player is admitted, preloads the destination, and shows a small Locating origin... status if extra search time is needed.

PER_PLAYER mode searches independently for each eligible new player instead.

Selector syntax

Biome selectors accept comma-separated exact IDs and tags:

targets = "minecraft:plains"
targets = "minecraft:plains,minecraft:forest"
targets = "#minecraft:is_ocean"

The same exact-ID / #tag form is supported by target, search-anchor, exclusion, required-neighbor, and structure selector fields where applicable.

Fallback behavior

VANILLA keeps the normal spawn if no candidate satisfies the configured rules.

RELAX_CONSTRAINTS keeps the target biome requirement but retries without the relative-position constraints. This is useful when reaching the requested biome matters more than satisfying every distance band.

Searches are bounded; impossible configurations do not intentionally search forever.

Admin commands

All commands require permission level 2.

• /biomespawn status — show active configuration summary
• /biomespawn preview — search for and describe a candidate without moving a player
• /biomespawn place — immediately resolve and place yourself
• /biomespawn place <player> — resolve and place another player
• /biomespawn reset — clear your first-placement marker
• /biomespawn reset <player> — clear another player's marker
• /biomespawn resetworld — clear the persisted WORLD-mode origin so a future eligible resolution can select a new one

Notes for pack authors

Relative geography can make first world creation take longer than vanilla because the mod may need to generate and inspect terrain before it accepts a location. The search planner first uses cheap biome-source information to avoid unnecessary generation, then validates actual terrain before accepting the final spawn.

When WORLD-mode origin resolution extends past vanilla spawn generation in singleplayer, the loading screen displays Locating origin... so the player knows the game is still working.

The selected WORLD origin is persisted, so normal later loads do not repeat the initial search.