Dangerous Structures

A Minecraft Forge mod that transforms structures into hostile territory. All structures — vanilla and modded — become permanent mob hotbeds where hostile creatures spawn around the clock, regardless of light level or time of day.

Features

Core

• Automatic structure detection — All registered structures (including modded) are dangerous by default
• Village exclusion — Villages are excluded by default, with a toggle to include them
• Structure whitelist/blacklist — Fine-grained control by ID or tag
• Mob whitelist/blacklist — Control which hostile mobs can spawn
• Dimension filtering — Choose which dimensions are affected
• Buffer radius — Expand structure boundaries for spawn detection
• Fully server-side — No client installation required

Spawning (v1.1.0)

• Structure piece-aware spawning — Targets individual rooms and corridors instead of the full bounding box
• Column-based floor finding — Efficient vertical scanning for valid spawn positions
• Pack spawning — Mobs spawn in groups matching vanilla pack sizes
• Vanilla spawn weights — Respects biome mob probabilities
• Hazard avoidance — Skips lava and water positions
• Difficulty scaling — Spawn cap and interval scale with Easy/Normal/Hard
• Night spawn boost — Configurable faster spawning at night
• Min player distance — Prevents mobs spawning on top of players

New in v1.1.0

• Initial population — 3-6 mobs spawn throughout a structure the first time it's discovered each session
• Armor system — Mod-spawned mobs are equipped with randomized armor (configurable tiers and drop chance)
• Fire immunity — Mod-spawned mobs receive permanent Fire Resistance to survive outside structures
• Admin commands — /ds status, /ds info, /ds list, /ds reload, /ds debug, /ds spawns, /ds validate
• Elite mob spawns — Rare enhanced mobs with boosted stats, glow, and bonus XP
• Environmental effects — Darkness effect and ambient sounds inside structures (opt-in)
• Mob persistence — Optional flag to prevent spawned mobs from despawning
• Mod API — Public API for other mods to register structures as dangerous
• Config validation — Warns about invalid structure/mob IDs on server start

Requirements

	Version
Mod	1.1.1
Minecraft	1.20.1
Forge	47.2.0+
Java	17+

Installation

1. Install Minecraft Forge for 1.20.1
2. Download the latest dangerousstructures-x.x.x.jar from Releases
3. Place the JAR in your mods/ folder
4. Launch the game — config generates on first server start

Commands

All commands require OP level 2. Available under /dangerousstructures or the alias /ds.

Command	Description
/ds status	Show mod status, config summary
/ds info	Show which dangerous structure(s) contain your position
/ds list	List nearby dangerous structures
/ds reload	Force-invalidate all caches
/ds debug [on/off]	Toggle debug logging at runtime (survives config reloads)
/ds spawns	Show spawn statistics
/ds validate	Re-run config validation and report issues

Configuration

The config file is generated at world/serverconfig/dangerousstructures-server.toml on first world load.

General

Option	Type	Default	Description
enabled	Boolean	true	Master enable/disable
autoDetectStructures	Boolean	true	Auto-detect all structures. When enabled, whitelists are ignored.
includeVillages	Boolean	false	Include villages when auto-detect is enabled

Structure Filtering

Option	Type	Default	Description
structureWhitelist	List	["minecraft:fortress", ...]	Structure IDs to make dangerous (manual mode only)
structureTagWhitelist	List	[]	Structure tags to include (manual mode only)
structureBlacklist	List	[]	Structure IDs to NEVER make dangerous (all modes)
structureTagBlacklist	List	[]	Structure tags to NEVER make dangerous (all modes)

Mob Filtering

Option	Type	Default	Description
mobWhitelist	List	[]	If non-empty, ONLY these mobs spawn. Priority over blacklist.
mobBlacklist	List	["minecraft:ender_dragon", "minecraft:wither"]	Mobs to exclude
dimensionSpecificMobs	Boolean	true	Pick mobs from the current biome's spawn list

Other Settings

Option	Type	Default	Description
allowedDimensions	List	["minecraft:overworld", ...]	Active dimensions
bufferRadius	Integer (0-16)	0	Extra blocks around structure bounds
debugLogging	Boolean	false	Log each spawn to console

Periodic Spawning

Option	Type	Default	Description
enabled	Boolean	true	Enable periodic forced spawning during daytime
spawnInterval	Integer (20-6000)	200	Ticks between spawn attempts
spawnCapPerStructure	Integer (1-64)	8	Max hostile mobs per structure
maxPositionAttempts	Integer (1-20)	10	Position attempts per spawn cycle
minPlayerDistance	Integer (0-48)	6	Min distance from players for spawns
chunkSearchRadius	Integer (2-8)	4	Chunk radius to search for structures
randomizeInterval	Boolean	true	Add jitter to prevent synchronized waves
useStructurePieces	Boolean	true	Spawn within individual structure pieces
weightPiecesByArea	Boolean	true	Prefer larger pieces (rooms) for spawning
useVanillaSpawnWeights	Boolean	true	Respect biome spawn weight probabilities
packSpawning	Boolean	true	Spawn mobs in packs
maxPackSize	Integer (1-8)	4	Maximum pack size
scaleCapByStructureSize	Boolean	false	Scale cap by structure footprint
mobsPerChunkArea	Integer (1-16)	3	Mobs per 16x16 area (when scaling)
maxScaledCap	Integer (1-128)	32	Absolute max cap (when scaling)
fireImmunity	Boolean	true	Grant permanent Fire Resistance (prevents sunlight burning, fire, lava, Fire Aspect)
persistentMobs	Boolean	false	Prevent spawned mobs from despawning
nightSpawnMultiplier	Double (1.0-4.0)	1.0	Night spawn rate multiplier
initialPopulationEnabled	Boolean	true	Spawn a group of mobs when a structure is first discovered
initialPopulationMin	Integer (1-16)	3	Minimum mobs for initial population
initialPopulationMax	Integer (1-32)	6	Maximum mobs for initial population

Armor

Option	Type	Default	Description
armorEnabled	Boolean	true	Equip mod-spawned mobs with randomized armor
armorDropChance	Double (0.0-1.0)	0.085	Drop chance per armor piece on death
allowLeather	Boolean	true	Include leather armor in the pool
allowChainmail	Boolean	true	Include chainmail armor in the pool
allowIron	Boolean	true	Include iron armor in the pool
allowGold	Boolean	true	Include gold armor in the pool
allowDiamond	Boolean	true	Include diamond armor in the pool
allowNetherite	Boolean	false	Include netherite armor in the pool

Difficulty Scaling

Option	Type	Default	Description
enabled	Boolean	true	Enable difficulty-based scaling
easyCapMultiplier	Double (0.1-4.0)	0.5	Cap multiplier on Easy
normalCapMultiplier	Double (0.1-4.0)	1.0	Cap multiplier on Normal
hardCapMultiplier	Double (0.1-4.0)	1.5	Cap multiplier on Hard
easyIntervalMultiplier	Double (0.25-4.0)	1.5	Interval multiplier on Easy (higher = slower)
normalIntervalMultiplier	Double (0.25-4.0)	1.0	Interval multiplier on Normal
hardIntervalMultiplier	Double (0.25-4.0)	0.75	Interval multiplier on Hard (lower = faster)

Environmental Effects

Option	Type	Default	Description
applyDarknessEffect	Boolean	false	Apply Darkness effect to players in structures
darknessAmplifier	Integer (0-4)	0	Darkness effect amplifier level
playAmbientSounds	Boolean	false	Play ominous cave sounds in structures
ambientSoundInterval	Integer (40-2400)	400	Ticks between ambient sounds

Elite Spawns

Option	Type	Default	Description
enabled	Boolean	false	Enable rare elite mob spawns
spawnChance	Double (0.0-1.0)	0.02	Chance for each spawn to be elite
healthMultiplier	Double (1.0-10.0)	2.0	Elite health multiplier
damageMultiplier	Double (1.0-10.0)	1.5	Elite damage multiplier
glowingEffect	Boolean	true	Elite mobs glow through walls
namePrefix	String	"Elite"	Custom name prefix for elite mobs
bonusXP	Integer (0-500)	20	Bonus XP when an elite is killed by a player

API

Other mods can interact with Dangerous Structures via DangerousStructuresAPI:

import com.otectus.dangerousstructures.api.DangerousStructuresAPI;

// Register a structure as dangerous
DangerousStructuresAPI.registerDangerousStructure(new ResourceLocation("mymod", "my_dungeon"));

// Check if a position is dangerous
boolean dangerous = DangerousStructuresAPI.isPositionDangerous(serverLevel, blockPos);

// Unregister
DangerousStructuresAPI.unregisterDangerousStructure(new ResourceLocation("mymod", "my_dungeon"));

How It Works

The mod uses three complementary mechanisms:

1. Initial population — When a structure is first discovered each session, 3-6 mobs are immediately spawned throughout its rooms and corridors. Uses aggressive position-finding (50 scan attempts) with distributed placement across structure pieces so mobs are spread naturally, not clustered.

2. Spawn event interception — Hooks into Forge's MobSpawnEvent.SpawnPlacementCheck and MobSpawnEvent.PositionCheck to force-allow hostile mob spawns inside dangerous structures, bypassing light level and time-of-day checks.

3. Periodic spawning — A server tick handler that maintains mob presence inside structures at configurable intervals. Uses structure piece-aware targeting, column-based floor finding, pack spawning, and hazard avoidance for efficient, natural-feeling spawns.

All mod-spawned mobs are equipped with randomized armor and granted Fire Resistance for sunlight immunity. Structure detection uses Minecraft's StructureManager with a fast-reject gate (hasAnyStructureAt) for efficient cross-chunk lookups.

Building from Source

git clone https://github.com/Otectus/Dangerous-Structures.git
cd Dangerous-Structures
./gradlew build

The built JAR will be in build/libs/.

License

This project is licensed under the GNU General Public License v3.0.