Part of the Base Building series:

Quick Answer

  • The Terrain Manipulator has four modes: Mine, Create, Flatten and Restore. Cycle them with the change-secondary-weapon input (middle mouse by default on PC).
  • It runs on an internal metal supply and is refilled by dropping Ferrite Dust or Silicate Powder onto it. It drains faster on Survival and Permadeath.
  • Restore mode is the most important one and almost nobody uses it. It undoes edits and hands you back terrain budget.
  • The game only tracks a limited amount of terrain editing across all your bases combined. Blow past that budget and old edits get forgotten, which is why your carved-out cave grows back.
  • Watch the terrain-edit indicator on your base. Green means you are within budget; anything else means something, somewhere, will regrow.
  • Flatten mode before you build, always. A level pad makes prefab rooms snap properly and saves an hour of fighting the grid.
  • The reliable way to hollow a clean space: place large square rooms, stack them to fill the volume, then delete them. That leaves a cavity that resists regrowth far better than digging does.
  • If a build depends on a hole you dug, it has a timer on it. Build on terrain, not inside it, unless you are prepared to maintain it.

Overview

The Terrain Manipulator is the tool everyone gets in the first hour and most players never think about again. It digs. You use it to reach a buried supply crate, and then you put it away.

That is a shame, because it is also the difference between a base that sits awkwardly on a slope and one that looks like it belongs there. Every good cliffside build, every underground hangar, every base with a level courtyard, started with someone spending twenty minutes on terrain before placing a single part.

It is also the source of the most confusing bug report in the game, "my base is full of rock again", which is not a bug at all but a budget you exceeded without knowing there was one. That is worth understanding before you commit to an underground build.

The Four Modes

Cycle between them with the change-secondary-weapon input. On PC that is middle mouse by default; on controller it is the corresponding face or bumper input, and it is worth confirming in your own control settings since the binding moves around.

Mine. The default. Removes terrain and collects the material it removes. This is what you already use.

Create. Adds terrain back, but not as it was. You are painting new material into the world. Useful for building ramps, filling holes, and sealing a tunnel behind you. It does not restore the original shape, which is what trips people up when they try to undo a mistake with it.

Flatten. Levels an area to a consistent height. Underrated and the mode most likely to improve your builds immediately.

Restore. Returns terrain to its originally generated state. This is the undo button, and it is the one that matters most for reasons covered below.

The tool draws on an internal metal supply that depletes as you work. Faster on Survival and Permadeath than on Normal. Refill it by dropping Ferrite Dust or Silicate Powder onto it in your inventory. Since mining terrain produces Ferrite Dust, the tool substantially fuels itself, and running dry usually only happens during a long Create-mode session where you are adding rather than removing.

Flatten Before You Build

This is the single most practical habit on this page.

Prefab base parts snap to each other, but their first placement snaps to the ground. Place a room on uneven terrain and everything downstream inherits that awkwardness: corridors at slight angles, doors that open into a hillside, floors that do not line up between wings.

The fix takes minutes. Pick your site, switch to Flatten, and level a pad noticeably larger than your intended footprint. Then build. Everything snaps cleanly, and you have room to extend later without re-terraforming around finished structures.

Do this even on ground that looks flat. "Looks flat" and "is flat" diverge more than you expect, and the base building basics get considerably easier once the ground stops arguing with you.

The Terrain Regeneration Problem

Here is the mechanic nobody tells you about, and it explains almost every strange thing you have seen terrain do.

The game stores your terrain edits, and the storage is finite. It is not per base. It is a single budget shared across every base in your save. Dig out a mountainside at one base and a cave system at another, and both draw on the same pool.

When you exceed it, the game starts forgetting the oldest edits. Forgotten edits mean the terrain reverts to how it generated, which is why players come back to a base and find rock growing through the floor, a doorway blocked, or a hollowed-out cavern filled in again.

Two things follow, and they change how you should build.

Watch the indicator. Bases show a terrain-edit status. When it reads green you are within budget and your edits are safely stored. When it does not, something is at risk, not necessarily at that base, since the budget is shared.

Restore mode buys budget back. Every edit you undo with Restore is an edit the game no longer has to remember. This is why Restore is the most important mode and the least used one. If you have dug speculative holes, tunnelled to a buried crate, or mined a deposit inside a base boundary, restoring those edits when you are done costs you nothing and protects the edits you actually care about.

Get into the habit: when you finish a build, sweep the site in Restore mode and undo everything that was not deliberate. Include the incidental mining you did inside the boundary. That counts too.

Building Underground Without Losing It

Underground bases are the most rewarding thing you can do with the Terrain Manipulator and the most fragile. Three techniques make them survivable.

Use rooms to carve, not the tool. The reliable method for a clean interior volume is to place large square rooms, stack and tile them to fill the space you want hollow, and then delete them. The resulting cavity holds up against regrowth considerably better than the same space dug out by hand. It is more work and it is the difference between a build that lasts and one that fills in.

Keep the budget clean everywhere else. An underground base is only as stable as your total edit budget. If you have three other bases with sprawling terrain work, restore what you can before starting.

Seal rather than leave open. A build that is a proper enclosed structure sitting in a cavity is more robust than one where the walls are raw terrain. Line the space with base parts. If terrain does creep back, it creeps back against a wall rather than through your floor.

Accept some maintenance. Even done well, an underground build may need occasional attention. Plan for it, and do not put your only storage containers somewhere that could get buried.

What Else It Is Actually For

Reaching buried technology. Buried Technology Modules and other underground caches are dug up with the Terrain Manipulator after locating them with the Survey Device. This is the backbone of salvaged data farming, which is how you unlock most base building blueprints.

Getting into and out of trouble. Digging into a hillside is an instant shelter from a storm, and it breaks line of sight from Sentinels. Both of which make it a survival tool more than a construction one. On a Permadeath run, knowing you can make a hole anywhere is worth real peace of mind.

Mining resource deposits properly. Large surface deposits are extracted much faster by digging into them than by beaming the surface. For anything more than a quick top-up, tunnel in.

Cave access. Caves are among the better base sites (naturally sheltered, atmospherically striking) and the Manipulator is how you widen an entrance enough to fly a ship near or fit a proper structure. See best base locations for what makes a cave site worth taking.

FAQ

How do I recharge the Terrain Manipulator?

Drop Ferrite Dust or Silicate Powder onto it in your inventory. It drains as you work, faster on Survival and Permadeath than on Normal. Because mining terrain yields Ferrite Dust, it largely refuels itself unless you spend a long session in Create mode.

Why does terrain grow back inside my base?

Because the game's terrain-edit storage is finite and shared across every base in your save. Once you exceed the budget, the oldest edits get forgotten and that terrain reverts to its generated state. Use Restore mode to undo edits you no longer need, which frees budget and protects the ones you care about.

What is the difference between Create mode and Restore mode?

Create adds new terrain wherever you point it, which is useful for ramps and filling gaps but does not recreate the original landscape. Restore returns terrain to how it was originally generated. Restore is the undo button; Create is a brush.

How do I make a clean underground room?

Place large square rooms and stack them to fill the volume you want hollow, then delete them. This produces a cleaner cavity than digging and resists regrowth far better. Then line the space with base parts so any creep meets a wall rather than your floor.

Does flattening terrain count against the edit budget?

Yes. All terrain modification counts, flattening included. That is not a reason to avoid it, a level build pad is worth the budget, but it is a reason to restore speculative digging you no longer need.

Can I terraform a whole planet?

No. Terrain editing is local and bounded, and it is stored as a set of changes rather than a rewritten planet. You can reshape a build site convincingly; you cannot change a planet's biome, weather or hazard level. Those are generated properties. See planet types and biomes.

Which mode do I use to fix a hole I dug by mistake?

Restore, not Create. Create will fill the hole with new material that rarely matches the surroundings. Restore puts the original landscape back and refunds the edit budget at the same time.

Key Takeaways

  • Four modes: Mine, Create, Flatten and Restore. Most players only ever use the first one.
  • Flatten a generous pad before placing any base part. Every snapping problem downstream starts with uneven ground.
  • Refuel with Ferrite Dust or Silicate Powder; mining largely keeps the tool topped up on its own.
  • Terrain edit storage is a single finite budget shared across all your bases. Exceed it and old edits are forgotten.
  • Restore mode is the undo button and the budget refund. Sweep your site with it when a build is finished.
  • Carve underground volumes by placing and deleting large rooms rather than digging. It holds up far better.
  • A build that depends on a hole is a build with a maintenance schedule. Line it with base parts and keep your budget green.