Terrain and generation reference

This page lists every control that changes elevation, with its real default, its real range and the engine key it writes. Colour controls live in Colour and climate reference; this page stops at the point where the heightmap is final. For the workflow around these controls, read Painting terrain and Enhancing terrain.

How to read this page#

The Engine key column names the field the control writes. Three kinds appear:

• Wire params. Keys of DEFAULT_PARAMS or of the POST /api/worlds/{id}/generate body. These reach the engine and are recorded in provenance.
• Request fields. Keys of a one-shot request such as the coastline apply payload or the Deterrace run. They are not persisted as world settings.
• Client state. Brush geometry that never leaves the app's own interface layer; it is turned into painted texels locally and only the resulting heightmap goes to the engine. These are marked client.

Ranges are the ones the control enforces. Where the API accepts a wider band than the slider offers, both are given. Every spatial figure is ground distance unless it says pixels.

Physical scale#

Scale is set once, in the setup wizard, and everything downstream is denominated against it. Changing it later means rebuilding the world.

A blank globe starts as a 4096 x 2048 equirectangular ocean planet with no continents and no seed.

Section geometry#

A region cut off the globe carries its own raster geometry. These are set in the region composer's Advanced controls.

Two extents exist and they are not interchangeable. selection_extent_km is the great-circle span of what you drew. extent_km measures the persisted raster, which includes the feather, so it runs about 20 % larger on a region with the default 32 px margin and about 45 % larger on a globe-colour tile. The Regions list and the section footer both quote the selection.

Hard limits: a section crop may not exceed 8192 px on an edge or 32 megapixels in total, and a selection whose farthest vertex sits more than 100 degrees from its centre is refused as not representable as one local section.

Sea level#

Sea level is 0 m by definition. Land is positive, ocean is negative, and every section carries its own decode contract:

elev_m = brightness x scale_m - depth_m

The Sea level slider#

At the top of the Height brush group in Draw mode.

At 0 or 1 the panel warns that the endpoint can leave an all-land or all-sea map with no usable coastline. Once a section has been through Generate, it also warns that moving sea level reclassifies land and ocean the model authored. Set sea level before you generate.

Sea level at import#

Authored once, in the wizard's Sea & terrain step, and written into the section's decode contract.

With a normalised heightmap, the value above the waterline maps as (b - s) / (1 - s) x peak_m and below it as (b - s) / s x depth_m, so the two branches are continuous and b == sea_level_norm is exactly sea level. A heightmap that encodes elevation and bathymetry as one continuous ramp implies depth = peak x s / (1 - s), which is what the inferred depth reports. The waterline can also be read off a land mask or a Köppen climate map of the same size rather than off the heightmap. See Setting up a world.

Sea level during Generate#

Both generation paths anchor the datum to the input: the model authors detail, the input owns sea level.

The height brush#

Four brush modes share one group. Set height is the continuous brush; Stamp, Landmass and Coast are placement tools and are covered further down.

Size#

The bounds are per section, so the slider always spans something useful. The size is shared with the Biome brush. A section that records no ground scale sizes the brush in texels instead and says so in the panel; its physical size then differs between sections.

Strength, flow and edge#

The pair of sliders under Size swaps depending on whether the mode is relative or absolute.

Set-height modes#

The floor and ceiling are the abyssal-plain reference the coastline tool uses and an above-Everest ceiling, so you can always paint outside the section's current range. When the target sits outside that range the panel warns that Apply changes will widen the span, and that the 16-bit height step grows with it.

The level palette#

Saved elevations that Deterrace later reads as its band centres. Add the current target with + Add current (n m); each saved level is a chip you can click to reuse or remove. [ and ] step the target through the palette in every mode except Relative. Alt-clicking the canvas samples the height under the cursor into the target.

Landform stamps#

One pointer-down places one landform. Dragging does not build it up. Each tile carries its own measured ground extent and relief, so placing one at 1x puts a real range down at the size that range actually is.

Jitter#

Categories are the tile bank's own feature classes: 1 Fold, 2 Block, 3 Rift, 4 Plateau, 5 Hills, 6 Volcanic, 7 Canyon, 8 Dunes, 9 Range, 10 Region. One is open at a time. The panel refuses to size a stamp on a section with no ground scale, and warns when the placement is wider than the section.

Landmass shapes#

A landmass placement writes no metres. It stages a land or sea decision, and the server turns the accumulated batch into terrain with a real continental margin. There is no cap on how many placements go into one coastline, which is what the panel means by PLACE AS MANY AS YOU LIKE.

Shapes are grouped by real size class: 1 Skerry (under 3 km across), 2 Islet (3 to 8 km), 3 Isle (8 to 20 km), 4 Island (20 to 50 km), 5 Large island (over 50 km). Above 5x the panel states plainly that the outline is no longer that island, it is that island's outline used as a continental silhouette. The shape stays plausible because coastlines repeat at every scale; the size is yours.

Coastline detail#

Shared with the Coast lasso: one settings object, one continental margin per section.

The outline you place is smooth at its new size, so this band re-injects real coast detail at the right physical scale.

Sea floor#

The coast lasso#

Trace a loop and the coast inside it is redrawn. Nothing outside the loop changes, the preview is live, and Revert is available after you apply. The lasso previews from the applied terrain, so it refuses to run while you have unapplied strokes.

Coastline shape#

Sea floor#

The lasso's preset differs from the landmass preset it inherits from: coast_bathymetry true, fidelity 0.2, coast_roughness 2.0, dejag_strength 12, octaves 4.

Coastline settings with no control#

These ship at fixed values on every coastline apply. They are on the wire, so the API can set them.

Deterrace#

Melts the risers of a contour-quantized heightmap into ramps while every pixel stays inside the elevation band it was drawn in. Land only: the sea floor is untouched.

The modal scores the section first and reports what share of land sits on a detected level. A low score discourages the run, it never blocks it. Running Deterrace invalidates a refined coastline, so refine the coast afterwards rather than before.

Terrain models#

The model is the scale contract. Its coarse cell is a fixed physical size, and the decoder super-resolves each cell to a fixed 256 x 256 block, so the cell size decides the feature scale of everything the model invents. Picking the wrong one gives you correct-looking terrain at the wrong scale.

90 m is the default and the recipe the reference world was generated with. Base-lite is our own whole-world model: it runs its own fixed recipe, bypasses the coarse grid the other two derive from your extent, and ignores precision, output resolution, SNR, rainfall and coastline settings.

The modal steers you between them:

• A 30 m run whose extent spans more than 128 coarse cells is flagged as beyond the continental threshold, with the note that 90 m matches the reference recipe at that size and keeps native output within reach of the combine ceiling.
• Base-lite below a 3000 km long edge is flagged because it invents roughly the 2.7 to 46 km band and adds nothing finer than about 2.4 km, so at that size the 90 m and 30 m models produce far more detail.

Which models appear depends on what is installed. The list is filtered to the server's allowed models, and base-lite additionally needs its runtime environment variables set.

The Generate modal#

Re-synthesizes the section's terrain at true physical scale, then colours it. Climate is inherited unchanged.

Model and precision#

Output resolution#

The modal states the resulting inference size, pixels per cell and approximate metres per pixel before you start. At or above a 4 GB estimated assembly it warns that the assembly canvas needs roughly that much system RAM while combining chunks, and that the final heightmap PNG will be similarly large.

Detail#

Three preset cards lead the section: Sketch (90 m, SNR 0.20, x1, the default), Faithful (30 m, SNR 0.05, x1) and Faithful, faster (90 m, SNR 0.05, x2). A preset sets model, SNR and feature scale together; moving any dial off a preset's exact values simply leaves the preset. The feature-scale slider shows the resulting effective cell size in km.

Rainfall conditioning#

The physical scale comes from the rainfall layer's own recorded millimetres per year at white. Only a layer with no recorded scale is read at the 3000 mm/yr default, which silently mis-scales a map exported at any other range. That failure is invisible: you get a plausible-looking world conditioned at the wrong climate.

Coastline#

The two are mutually exclusive by validation: asking for coastline enhancement while the model authors the coastline is a 422. On whole-world globe runs model_authors_coastline is forced off, because the open-ocean land-scatter regression is still open.

The fixed part of the recipe#

The modal pins these and states so: "Addon parity: 16-cell chunks, 3-cell overlap, de-block on, bathymetry on, deep-ocean skipping, 0 m water level, retained chunk tiles, and no relief-body remap." They are all on the wire, so the API can change them.

Two notes on use_bathymetry. Turning it off does not mean land-only or ocean-at-zero: it keeps a constant ocean floor at ocean_floor_depth_m (6000 m). The model was trained on real DEMs where the sea floor is negative metres, so an ocean at zero reads as flat coastal land and the model invents random coastal relief. A constant floor anchors the coastline in the conditioning itself. Second, conditioning is rebuilt from the authored land heightmap and bathymetry on every run, never from the previous generation's output, so a repeated Generate does not ratchet the sea level upward.

Relief matching#

Two post-processes exist that reshape the model's land body against your input. Both are off, both are reachable only through the API, and both exist for a specific defect.

relief_body_match is not part of the reference recipe. Turn it on only when you have looked at a render and can name the flat interior it is meant to fix.

Grain rolloff#

Base-lite output carries a rising near-Nyquist tail that aliases into moiré under fractional zoom (measured at 18.7 times real terrain's power at 2 px). Every base-lite pass therefore runs a calibrated radial 13 x 13 FIR rolloff over the deviation from the guide, after stitching and after relief matching.

It is on by default, it is not exposed in the interface, and the server never passes the tool's --no-grain-rolloff flag. Because it filters the deviation and not the guide, authored detail survives untouched, and because the kernel is translation-invariant it is seam-safe across tiles. Content at 4 px and coarser is unaffected.

This applies to base-lite only. The 30 m and 90 m models do not run it.

Revert and snapshots#

Generate takes a snapshot of the hand-authored heightmap before the first run on a section, and Revert to authored heightmap in the modal footer restores it. Deterrace keeps its own snapshot, restored with Revert to previous heightmap. Both buttons appear only when a snapshot exists. A revert protects future generates; it does not undo a generate you have since built on.

Defaults worth leaving alone#

• snr_elev at 0.20. Small values mean strong adherence to your terrain. Raising it loosens the model from what you painted, which is rarely what someone reaching for a "more detail" slider wants. 0.20 is the value the terrain-diffusion author recommends for imported heightmaps, and it is what the model's own CLI ships as its default. The one deliberate departure: drop to 0.05 for coastal fidelity when a model-authored run must respect authored shallows and island layouts.
• The model choice. The coarse cell is a physical contract. A 30 m run on a continental extent produces mountains at the wrong size, and the result looks right until you measure it.
• use_bathymetry on. Off means a constant 6000 m floor, and the constant floor is doing real work. Neither setting gives you an ocean at zero.
• relief_body_match and lowfreq_land_swap off. The second one drowns a third of the authored land on low-lying worlds. It exists to rescue a pathological run, and nothing else.
• Sea level before Generate. Moving the waterline afterwards reclassifies land and ocean the model authored, and the editor says so.
• Grain rolloff on. Stripping it puts moiré into every base-lite world at viewer zoom. If the model is ever retrained the rolloff's calibration constants have to be re-measured against the new output, not just carried over.
• precip_max_mm at 3000. It is only read when your rainfall layer records no scale of its own. Changing it to match a map that does record a scale changes nothing, and changing it blind mis-scales the climate conditioning invisibly.