Tunnelheim

v1.0.0·Updated 2026-10-09

The vanilla pickaxe digs real tunnels in any direction. Shape rock with the hoe, climb ladders, light the dark with glow moss and crystals, grow mushrooms underground, and flood tunnels from the sea.

About this mod Author’s original text

Tunnelheim

The vanilla pickaxe digs real tunnels. Swing into a hillside and the rock opens up in whatever direction you swing: in, up or down. No new tools are needed to dig; everything is built on the game's own pickaxe, hoe, cultivator and hammer.

Digging

  • Any pickaxe digs. Better pickaxes take bigger bites: antler 1 m, bronze 1.25 m, iron 1.5 m, black metal 1.75 m. Dug rock drops stone.
  • Undo (U): takes back your last dig, Add Earth or Smooth Surface. Press again to go further back, up to 20 steps.
  • Dig straight (H): the pickaxe takes nothing below your feet, so tunnels keep a flat floor.
  • Square digs (F7): switches between round digs and square digs lined up with where you face, for straight walls.
  • Ore deposits show up in tunnel walls in ore biomes where digging exposes a vein, more often deeper down.
  • Trees fall over, and stumps and bushes break, once the rock under them is dug away.

Shaping rock

The hoe works on dug rock the way it works on the ground: level, raise and pave. It also gets:

  • Add Earth (2 stone): packs rock onto a floor, a wall or a ceiling.
  • Smooth Surface: flattens rock at the angle of the surface you aim at. Q / E lock and tilt the angle; G goes back to following the surface.
  • Level Wall and Level Ceiling: square up a room.

Rock can be built up to 64 m above the original ground.

Building and lighting

  • Ladder (6 wood, workbench): climb shafts. Use it to hold on, forward and back to climb, run to climb faster or to slide down.
  • Crystal Light (2 crystal, workbench): frost-cave crystal that glows without fuel, on any floor, wall or ceiling.
  • Glow Moss (1 Cave Moss): a dim glowing moss patch for rock floors, walls and ceilings. The workbench makes 20 Cave Moss from 1 guck.
  • Deeper in, the daylight fades and the biome music stops. Seen from outside, tunnel walls darken the deeper they go.
  • Chests you bury under rock still show up to the Wishbone.

Underground farming

Every mushroom can be planted with the cultivator on cultivated ground with a roof overhead: a tunnel, a cave or a building. They don't grow under the open sky (Magecap and Jotun puffs still grow in the open in the Mistlands, as usual). Pits open to the sky grow crops like any field.

Water

Tunnels below sea level stay dry until you break into the sea. Then the water floods in, rising only to the top of each opening. Seal the breach and the tunnels drain.

Biomes

  • Mistlands: the mist stays outside the tunnels.
  • Ashlands: dig into a lava field and the pit stays lava; tunnel beneath it and stay dry.
  • Deep North: snow stays on dug rock.

Map

  • Tunnels you've been within 100 m of are drawn on the large map, wherever the map is explored. They're kept with your character for each world.
  • Deep underground, the map dims and shows tunnels by height: your level brightest, deeper darker, higher paler, open sky gold. L on the large map switches between the surface and underground views. A checkbox on the large map hides the tunnels.
  • Your height above or below sea level shows under the minimap.

Controls

| Key | Does |

|---|---|

| U | Undo your last dig, Add Earth or Smooth Surface (up to 20) |

| H | Dig straight on and off |

| F7 | Round or square digs |

| Q / E | Smooth Surface: lock and tilt the angle |

| G | Smooth Surface: follow the surface again |

| L | Large map: surface or underground view |

Every key can be changed in the config. The mod's keys do nothing while you type, or while Alt or Ctrl is held.

Configuration

BepInEx/config/sam.valheim.tunneling.cfg. Settings that change the shared world (build height, ore veins, falling trees) follow the server's config in multiplayer.

Multiplayer

Everyone, the server included, needs the mod at the same version. Jotunn refuses the connection otherwise.

Before you install or remove it

  • Back up your world. Tunnels are stored in the world as objects only this mod knows. Remove the mod and the game deletes them when their areas load: the ground comes back as it was.
  • Older versions o

Install & use Install: BepInEx plugin

  1. The archive from playbuff is the mod itself — usually a BepInEx plugin (a .dll or a plugin folder once unzipped).
  2. Recommended: use a community mod manager (such as r2modman) — pick this game, import the mod, and the manager sets up BepInEx and its dependencies for you.
  3. Manual route: install the BepInEx loader in the game folder, then drop the unzipped .dll or plugin folder into BepInEx/plugins/.
  4. Launch the game — the BepInEx console logs every plugin it loads; seeing this mod in the log means it is installed.

Mods with listed dependencies need those installed too, or they will not load. Options are usually changed in-game or in the plugin's config file. In multiplayer, the host and every client need the same mods installed.

Dependencies

Install these first, or the mod will not work:

ValheimModding-Jotunndenikson-BepInExPack_Valheim

File & checksum

Filename
Tunnelheim-1.0.0.zip
File size
433.2 KiB