Fortress
Bastion
Ruined PortalType your seed and pick your edition; the map regenerates instantly. The map shows your Nether's terrain at lava level (y=31), with every lava lake, fortress, bastion, and ruined portal for your seed.
Drag to pan, scroll or pinch to zoom, double-click to dive in. Right-click (or long-press) drops a waypoint. Keys: + - zoom, arrows pan, / jumps to the seed box. The address bar always holds your exact view, so any link you copy opens right here.
Terrain density is about 90% accurate to vanilla generation. The rest comes from Nether cave carvers, which hollow out tunnels after density is computed, so small carver lava pockets aren't modeled.
Structure positions come from the exact placement math for both editions. More in the reference section below.
Built using the cubiomes library by Cubitect and the Bedrock fork by Reed Cartwright.
Bedrock structure placement uses the MT19937 PRNG algorithm with grid parameters validated against community research and in-game testing.
Reference: How This Map Works
Most Minecraft map sites use biome data to drive their visuals. That works in the Overworld, where oceans and rivers are distinct biomes, but the Nether doesn't define lava lakes or rivers as biomes at all, which is why traditional Nether maps lack practical detail. This map takes a different approach.
Why a terrain density map instead of a biome map
This map reimplements Minecraft's Nether terrain density function. Instead of relying on biome data, it generates a snapshot of terrain density at y=31, the level where lava lakes form. Anywhere the density function says "no terrain" at that level is lava; everywhere else is solid ground you can walk or tunnel through.
That's what makes the map practically useful: you can see the actual shape of lava lakes, coastlines, and mineable ground for your exact seed, not just which biome you'd be standing in.
Overhangs: the second terrain layer
When the Overhangs layer is on, an additional terrain density layer is generated at a customizable Y-level (default y=40, to show overhangs near lava level). It renders as a lighter, dithered shade over the lava.
The Y-level is adjustable in the Layers panel. For example, if you want to build a Nether highway at y=90, set the overhang level to 90 and you'll see exactly what terrain exists up there. For a clean view of just the overhang layer, switch off "Lava-level terrain".