Sparse Structures

Overview

Sparse Structures is a lightweight utility mod that adjusts how far apart all structures spawn in your world. By default, it doubles the spacing and separation values for every Structure Set in the game, making Villages, Temples, Strongholds, and all modded structures roughly twice as rare. This applies to vanilla structures, modded structures, and even datapack structures automatically.

The mod works through Minecraft's mixin system, intercepting structure placement data during world generation and multiplying spacing values by a configurable factor. It does not add any items, blocks, or crafting recipes. Instead, it provides a single configuration file where you control exactly how rare or common each structure should be. If you're running a modpack with dozens of structure mods and finding a new Village every hundred blocks, this is the mod that fixes that problem.

Beyond basic rarity control, Sparse Structures also fixes the vanilla bug MC-177381 (where the /locate command reports incorrect distances), removes the 4096-chunk separation limit that vanilla imposes, and generates unique salts per structure to prevent clustering. You can browse detailed configuration options throughout this guide.

Configuration

All configuration lives in a single file: config/sparsestructures.json5. The file uses the JSON5 format, which supports comments. There are three settings that control how the mod behaves.

spreadFactor (Global Rarity)

The spreadFactor is a multiplier applied to every structure's spacing and separation values. The default value is 2, meaning structures spawn with twice the distance between them. A value of 1 leaves structures at their vanilla or modded defaults. Values below 1 (like 0.5) make structures more common. A value of 0 disables all structures entirely. Decimal values are supported, so 1.5 would make structures 50% rarer.

The mod multiplies both the spacing (maximum distance between structures) and separation (minimum distance between structures) by this factor. If the calculated separation ends up equal to or greater than spacing, the mod automatically corrects it by setting separation to spacing minus 1, ensuring valid generation parameters.

idBasedSalt (Anti-Clustering)

When idBasedSalt is set to true (the default), the mod generates a unique salt value for each Structure Set based on a hash of its ID. The salt is calculated as the absolute value of the structure ID's hash code modulo Integer.MAX_VALUE. This is important because many modded structures leave their salt at 0 or use the same default value, which causes different structures to cluster together in the same chunks. With unique salts, each structure type gets its own independent placement grid, spreading them out much more evenly across the world.

customSpreadFactors (Per-Structure Control)

The customSpreadFactors array lets you override the global spreadFactor for specific structures. Each entry needs a structure field (the namespaced ID) and a factor field (the multiplier). You can target either a Structure Set ID (like "minecraft:villages") or an individual structure name (like "minecraft:village_plains"). When you target an individual structure, all structures within that same set are affected.

The custom factor completely replaces the global factor for that structure, it does not stack on top of it. If your global spreadFactor is 2 and you set a custom factor of 3 for Villages, Villages will be 3x rarer (not 6x). Setting a custom factor of 1 effectively exempts a structure from the global modifier. Setting it to 0 disables that structure entirely.

How It Works Under the Hood

Sparse Structures uses three mixins to modify Minecraft's world generation. Understanding what they do helps explain the mod's behavior and limitations.

Structure Spacing Modification

The core mixin intercepts Minecraft's registry data loader as it reads Structure Set JSON files. For every Structure Set that uses random spread placement (which is most structures), the mod multiplies the spacing and separation values by the appropriate spread factor. Structures using concentric ring placement (like Strongholds) are left untouched, since their placement system works fundamentally differently.

When a structure's spread factor is set to 0, instead of modifying spacing, the mod sets the structure's frequency to 0, effectively preventing it from ever generating.

Separation Limit Removal

Vanilla Minecraft caps the maximum separation between structures at 4096 chunks (65,536 blocks). The mod removes this cap by replacing the constant with Integer.MAX_VALUE (2,147,483,647). While most players will never need structures to be this rare, it ensures that extremely high spread factors work correctly without being silently clamped.

/locate Distance Fix

The mod fixes Minecraft bug MC-177381, which caused the /locate command to report incorrect distances between the player and located structures. The fix replaces vanilla's distance calculation with a proper Euclidean distance formula using Math.hypot(), giving you accurate distance readings when locating structures.

Common Configuration Examples

Here are some practical config setups for different play styles and modpack scenarios.

Heavy Modpack (Lots of Structure Mods)

If you're running modpacks with mods like Explorify, YUNG's Better Structures, Towns and Towers, and Dungeons and Taverns all at once, a global spreadFactor of 2 or 3 prevents the world from feeling like an overcrowded theme park. Leave idBasedSalt enabled to prevent structures from different mods clustering in the same area. You can then set specific important structures (like Villages) to a custom factor of 1 to keep them at normal rarity since they provide essential Villager trading.

Hardcore / Survival Challenge

For a challenging survival experience where structures are genuinely rare and valuable to find, set the global spreadFactor to 5 or higher. Finding a Village becomes a significant event rather than a routine occurrence. Combine this with custom factors of 1 on Strongholds so End progression remains achievable, and consider leaving Nether Fortresses at a lower factor since they're required for Blaze Rods.

Selective Structure Disabling

Set the global spreadFactor to 1 so most structures remain normal, then use customSpreadFactors to disable specific structures by setting their factor to 0. This is useful when two structure mods add similar buildings and you want to keep only one, or when a particular structure causes performance issues or conflicts with your world's aesthetic.

Compatibility

Sparse Structures works with virtually all structure mods and datapacks because it operates at the registry level, modifying Structure Set data as it's loaded regardless of which mod registered it. This means mods like YUNG's Better Dungeons, Repurposed Structures, Towns and Towers, and any other structure mod are automatically affected without needing specific compatibility patches.

There is one notable exception: the mod is incompatible with Cyanide, which also modifies structure placement data. Structures using concentric ring placement (primarily Strongholds) are not affected by the mod, as their placement system is fundamentally different from random spread.

The mod does not alter ore generation, geode placement, or other non-structure world generation features. Terrain and tree generation are affected very slightly (due to how structure placement influences chunk generation order), but not enough to be noticeable in normal gameplay.