Border Expands per Achievement - Progressive World Expansion

Many Minecraft worlds feel too large early on, reducing the need to explore or cooperate. This data pack solves that by tying the world border directly to player achievements. Starting at a tight 50x50 block area (radius 25), the border expands only as players earn advancements. This creates a natural progression where the world grows with your progress, encouraging teamwork and focused exploration without overwhelming new players.

The expansion is precise and predictable: each advancement earned by any player increases the diameter by exactly 50 blocks, adding 25 blocks to the radius. After the first achievement, the border becomes 100x100 (radius 50); after the second, 150x150 (radius 75), and so on. The pack includes a hybrid Nether-scaling system that adjusts the Nether border independently, ensuring the overworld and Nether stay balanced for co-op play. It is lightweight and tested for minimal server lag even with many players.

This pack is ideal for multiplayer servers, adventure maps, and challenge groups where you want to force players to work together and earn their space. Solo players can also use it to add a self-imposed challenge. The border remains centered at world spawn (0,0), so building near the center is wise. Note that the border does not shrink if players lose achievements (not possible in vanilla), and it only expands—making the game progressively easier in terms of available space. The pack does not modify advancement logic or add custom achievements; it uses the vanilla advancement tree.

• Starts small: 50x50 blocks, forces early cooperation and resource sharing.
• Expands per achievement: Each advancement earned by any player adds 50 blocks to the diameter.
• Nether scaling: Hybrid system adjusts Nether border independently to avoid exploits.
• Lag-free: Only runs a few scoreboard checks per tick, no heavy loops or entity scans.
• Multiplayer ready: All players contribute to expansion; no per-player borders.

Requirements: Minecraft Java Edition 1.21 or later (uses new advancement triggers). Place the data pack in the world's datapacks folder. Works on servers and single-player. The pack does not alter achievements or recipes; it only listens for advancement events. Nether and End borders scale based on world-specific rules; the End dimension uses the same overworld border. For best results, start a new world with the pack installed.