Genesis - World Previewer & Pregenerator

See the world before you make it. Genesis puts a live biome map, seed tools and world pre-generation on the Create New World screen, so you can compare seeds and pre-build the terrain before you ever spawn in.

Minecraft 1.21.1 on Fabric or NeoForge, and 1.20.1 on Fabric or Forge. Needs Architectury API.

⭐ What It Does

• A biome map of the world you are about to create - opened from a GENESIS button on the Create New World screen, sampled from the real generator with your seed and every mod you have installed.
• Readable in seconds - a coarse pass fills the layout immediately, then two finer passes complete the detail, sampling across as many as 16 background threads.
• Fixed at Y = 320 - so cave biomes never bleed into the surface map.
• Colored so you can actually read it - 16 biome families share a fill color, and every individual biome gets its own border color in the legend.
• Modded biomes get real colors too - matched by registry name, then grass color, then a hash of the name, so nothing shows up as anonymous gray.
• Pan, zoom and measure - drag to pan, scroll to zoom, NEAR, MID and FAR for fixed levels, with a scale bar, a live legend and a coordinate and biome readout under the cursor.
• Seed tools where you need them - type a number or any text, RANDOM for a fresh one, COPY to the clipboard, R to reroll. Leaving the screen writes the seed back to Create New World for you.
• Pre-generate before you play - set a radius and thread count and watch a progress bar with a chunk counter, a rolling ETA and the active dimension.
• On your terms - PAUSE and RESUME without losing progress, CANCEL to stop, or ENTER WORLD to keep it running in the background.
• A HUD while it runs - dimension, chunks, percentage and ETA at the top of the screen, amber while paused, gone when the job finishes.
• Or drive it from commands - /genesis pregen by dimension or all, optionally centered on explicit coordinates, with cancel, pause, resume and status, plus /genesis info for the seed and generator.
• A broken generator never takes the screen down - tiles that fail to sample are drawn neutral gray and the preview carries on.

📋 Requirements

• Minecraft 1.21.1 on Fabric or NeoForge, and 1.20.1 on Fabric or Forge.
• Architectury API 13.0.8 or later on every loader.
• Fabric API 0.116.12 or later, Fabric Loader 0.19.2 or later, and Cloth Config 15.0.140 or later, on Fabric.
• NeoForge 21.1 or later, on NeoForge.

📥 Installation

1. Install your loader and Architectury API, plus Fabric API and Cloth Config if you are on Fabric.
2. Install with the Modrinth App, or download the jar for your version and loader into your mods folder.
3. Open Create New World. A GENESIS button sits on the screen.

⚙️ Configuration

On NeoForge, edit config/genesis-client.toml. On Fabric, edit config/genesis.json or use any Cloth Config-compatible in-game editor.

A change takes effect the next time the preview restarts, on a seed change or when the screen reopens. NeoForge enforces the ranges; the Fabric file takes what you type for the three preview options, so keep them inside those ranges yourself.

🖥️ Compatibility

• Existing worlds. The preview only runs on the Create New World screen, so it changes nothing about a world you already have. Pre-generation can be pointed at one from a command.
• Client or server. The biome preview is entirely client-side and safe to install on the client alone. Pre-generation needs Genesis on the server too, or on the integrated server in singleplayer.
• It does not touch generation. The preview reads the generator; it changes no chunk, structure or loot table.
• Worldgen mods such as Tectonic and TerraBlender are reflected accurately, because Genesis samples the same generator that builds the real terrain.
• GeoGradient is detected automatically: the map shows its latitude-based climate bands with no extra setup.
• Custom and Superflat generators fall back gracefully, showing biome colors where they can.
• Commands are operator level 2 on a server and unrestricted in singleplayer; status and info are open to everyone.

🐛 Support

• Report bugs and ask questions on this mod's Nexus Mods page, where every report is tracked.
• Include your Minecraft version, your loader and its version, the mod version, and your other mods.

📄 License

License terms are in the Alkeari License Agreement.