13 · Terrain

Three tools shape the landscape: Terraform generates it procedurally, the Terrain Editor corrects it by hand, and the Mission Area Editor bounds and mirrors it. All three write to the .ter file.

Terraform Editor — the procedural stack

The most capable and least known part of the toolchain.

“Heightfield operations are arranged in a stack, with some operations using the results of previous operations to produce new heightfields. The results of the last operation on the stack can be applied to the terrain using the Apply button.” [script]

Two panes: the top inspects the selected operation, the bottom shows the stack, with a pull-down between them for adding operations. The first entry is always General and cannot be deleted.

The fourteen operations

Three of those deserve emphasis.

The erosion operators are real erosion simulations. Thermal erosion models material sliding down slopes past an angle of repose; hydraulic models material carried by water. Running a fractal and stopping is what makes terrain look generated; running an erosion pass over it is what makes it look weathered.

Blend and Turbulence make it a compositor, not a generator. Because operations consume earlier results, you can build genuinely layered terrain — Rigid Multifractal for the major ridgelines, blended with fBm at low weight for surface detail, turbulence to break up the regularity, then hydraulic erosion. That is a modern heightfield workflow, in a 2001 game, in-engine.

Bitmap and Terrain File are the import paths. Bitmap takes a 256×256 image as the heightfield — so any external terrain tool that can export a greyscale heightmap can feed this. Terrain File puts an existing .ter on the stack, which combined with File ▸ Import Terraform Data… means you can start from a shipped map’s recipe.

Reading a shipped recipe

The single most efficient way to learn what produces Tribes-like terrain:

1. File ▸ Import Terraform Data… and pick a shipped .ter.
2. Open the Terraform Editor and read the stack.
3. Change one operation’s parameters and Apply.

The rules live in the .ter file itself, so every shipped map carries its own generation recipe.

Save before Apply. The manual warns that “Not all actions can be undone” [script], and a terraform Apply rewrites the whole heightfield.

Export Terraform Bitmap… (File menu, active only in this editor) writes the current map out as a bitmap — useful for taking a heightfield to an external tool, or for documentation.

Terrain Editor — manual brush work

Corrections and detail after generation.

“Terrain editing is accomplished using the brush. The brush is a selection of terrain points or squares centered around the mouse cursor.” [script]

Soft-brush falloff is controlled by the filter view in Terrain Editor Settings.

The eleven action modes

From the Action menu [script]:

Set Empty is the one to know about. It punches holes in the heightfield, which is how you build terrain that a player can pass through rather than over — cave mouths, sunken bases, anything where an interior needs to breach the ground plane. Those holes are stored per-square in the .ter and appear in the .mis as the emptySquares field on TerrainBlock [script]:

new TerrainBlock(Terrain) {
   detailTexture = "details/lushdet2";
   terrainFile = "Slapdash.ter";
   squareSize = "8";
   emptySquares = "94579 99875";
      visibleDistance = "1200";
      hazeDistance = "250";
};

Select / Adjust Selection is the precision path. Rather than dragging heights freehand, select a region with the brush then move the whole selection as a unit — the right way to level a base footprint.

The TerrainBlock fields you will set

visibleDistance and hazeDistance are performance and atmosphere in one pair. Shipped maps use 1200 / 250 [script].

Mission Area Editor

Bounds, centring and mirroring.

“The Mission Area Editor displays an overhead height map in the upper right corner of the screen, with markers for mission objects, a box for the mission area and a pair of lines denoting the current field of view. Clicking anywhere on the display will move the current view object (either camera or player) to that location.” [script]

That click-to-teleport is the fastest way to navigate a large map while editing — better than flying.

Mirroring is how you make a fair competitive map. Two-team symmetry matters in CTF, and mirroring the terrain across a plane guarantees it. Note it mirrors terrain, not objects — you still place and mirror the bases yourself.

MissionArea in the .mis

new MissionArea(MissionArea) {
   area = "-848 -864 1264 1472";
   flightCeiling = "240";
   flightCeilingRange = "20";
      locked = "true";
};

Leaving the play area open is a real design failure: $DamageType::OutOfBounds exists (Damage and type masks) and gametypes call testOOBDeath [script], so the boundary is enforced — but only where you have defined it.

Terrain from script

A small console surface exists [binary]:

getTerrainHeight(pos);
makeTestTerrain(fileName, {dml1, dml2, ...dml8} );
echoTerrainTextures();

getTerrainHeight is the useful one for a mod — Construction’s deployables use raycasts rather than this, but for anything that needs ground level at a coordinate it is the direct route.

Note makeTestTerrain takes up to eight .dmls — the same eight-material ceiling the painter works against (14).

Related

• 14 · Terrain texturing — materials on top of this geometry
• 12 · World Editor — placing objects on it
• 15 · Lighting, navigation & spawn data — what to regenerate after terrain changes
• File formats — .ter, .dml