RenderFast

A professional, high-performance chunk pre-generator for Minecraft (Fabric).

RenderFast eliminates chunk-loading stutter by pre-generating terrain before you start exploring. Its fully asynchronous loading pipeline is built to saturate your CPU and SSD, while aggressive watchdog protection and adaptive throttling keep the server stable.

[!IMPORTANT] RenderFast includes native support for Voxy (Iris LOD) and Distant Horizons, so LOD data is correctly finalized and saved during pre-generation without overloading the async pipeline.

[!CAUTION] PERFORMANCE IMPACT: Generating chunks is a heavy task. While preloading is active you may see lower TPS and occasional stutters. Use Turbo Mode with extreme caution, as it bypasses all safety limits.

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Key Features

• Extreme Speed: Fully asynchronous pipeline with "Immediate Refill" logic and throttling to prevent main-thread hangs.
• Watchdog Breather & Lag Recovery: Yields to the server before a slow tick can trigger the 60s Watchdog crash, then waits for the server to recover before resuming.
• Smart Throttling: Real-time monitoring of TPS, RAM (with Auto-GC), and disk space.
• LOD Mod Sync: Native integration with Voxy and Distant Horizons.
• Map Mod Sync: Support for BlueMap, Dynmap, and Xaero's Map.
• Multi-Dimension Sequencing: Moves from Overworld to Nether to End in a configurable order.
• Priority POIs: Generate specific coordinates or structures before the main spiral.
• Detailed HUD: Progress bar with pause reasons (LOW RAM, BUSY TICK, LAG RECOVERY), speed, and ETA.
• Lighting Fix Mode: A light-only engine that fixes dark/black chunks in existing worlds.
• Player Safety Bubble: Force-loads the area around online players to prevent exploration lag.
• Full Control: Every setting is available through in-game commands or a custom Pause Menu UI.

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Commands

All commands require OP level 2 and work with both /renderfast and the /rf alias.

Control

Command	Description
/rf start [radius] [x] [z]	Starts preloading. Radius and coordinates are optional.
/rf pause / resume	Temporarily halts or continues the current task.
/rf stop	Cancels all tasks immediately.
/rf reset	Restarts the current task from 0% at your position.
/rf status	Shows progress, speed (ch/s), dimension, and ETA.
/rf turbo	Toggles Turbo Mode (bypasses safety throttles).
/rf help	Quick in-game reference for all commands.

Safety & Tools

Command	Description
/rf breather [ms]	Toggles or sets the watchdog protection threshold.
/rf recovery <ms>	Sets how long to wait before resuming after lag.
/rf border	Preloads everything inside the current world border.
/rf dryrun	Shows the target area corners using particles.
/rf estimate	Estimates final disk space usage for the run.
/rf report <seconds>	Sets how often progress is logged to the console.
/rf webhook <url|clear>	Configures Discord alerts for task completion.
/rf poi <add|clear>	Manages coordinates generated before the main task.
/rf oncomplete <cmd>	Runs a command when a dimension finishes.

Configuration (/rf config ...)

Sub-Command	Description
enable / hud / metrics / minimap	Toggle the engine, HUD, speed/ETA display, or HUD heatmap.
dh / voxy	Toggle Distant Horizons or Voxy sync.
refill / gc / adaptive	Toggle Immediate Refill, Aggressive GC, or adaptive throttling.
radius <val>	Generation radius (1-2048).
shape <CIRCLE/SQUARE>	Generation area shape.
cpu <PROFILE>	Presets: LOW, MEDIUM, HIGH, VERY_HIGH, INSANE.
ram <%>	RAM threshold (1-100) before auto-pausing.
disk <MB>	Minimum free disk space required to run.
timeout <sec>	Seconds before a "stuck" chunk is retried.
safety <radius>	Player safety loading radius (0-16).
saveinterval <val>	Chunks between forced world saves.
workhours <start> <end>	Active hours (0-23).
status <status>	Target generation depth (default: minecraft:features).

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Configuration Screen

Open the visual settings via Mod Menu, a keybind in your Controls menu, or the RF button in the Pause (ESC) menu (left of the Options button).

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Requirements

• Minecraft: 26.2
• Loader: Fabric
• Dependencies: Fabric API, Cloth Config

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Good to Know

• Speed vs. Quality: The default minecraft:features status generates terrain, trees, and ores at roughly 2x the speed of full. It's recommended for standard survival pre-generation.
• Turbo Mode: Best used on empty servers. It ignores TPS and Busy Tick checks to maximize SSD write speed.
• Singleplayer Pause: Opening the Escape menu freezes the world, which also pauses generation. Stay in the Options or RenderFast Config screen if you want preloading to continue.

License

Licensed under ARR (All Rights Reserved). No redistribution, modification, or commercial use is permitted without explicit written permission.