What modifiers are

A modifier is a named operation stored on a layer, a category within a layer, or a single feature. Modifiers are non-destructive: they describe a transform to apply on top of the source data rather than replacing it. The result is computed each time the project is rendered or exported.

Some modifiers are persistent — they stay on the layer and re-apply whenever the project is opened. Others are one-shot operations that run once and store their result. The modifier panel presents both types in the same interface.

Open the modifier panel with the M key, or by right-clicking a layer, category, or feature in the Layers panel and selecting Open modifiers.

Modifier scoping

Modifiers can be scoped to three levels.

• Layer — the modifier applies to all features in the layer.
• Category — the modifier applies only to features in a specific category within the layer.
• Feature — the modifier applies to a single selected feature.

Vector modifiers

The following modifiers work on vector layers and their features:

• Offset — shrinks or expands polygon geometry by a distance in metres. Positive values contract; negative values expand.
• Buffer — generates a filled polygon overlay around a polyline feature at a configurable radius. Useful for road or river shoulders.
• Smooth — rounds sharp corners using Chaikin curve subdivision. The smoothing window (in metres) controls how aggressively short edges are cut, and the number of passes controls how many rounding iterations are applied.
• Refine — cleans up polyline linework by rounding corners and, when enabled, snapping nearby endpoints into cleaner junctions. Useful for roads, streams, and other imported network geometry.
• Rectangulate — snaps corner angles to 90° to produce clean rectangular shapes, useful for buildings and field corners.
• Cut Bounds — clips vector geometry to a selected boundary role (playable area, playable bounds, or background zone), with an optional inset in metres.
• Classify — transfers categories from another vector layer to this one by polygon intersection, letting you inherit field or zone types from an external source.
• Depth — carves terrain beneath vector polygons by a specified depth in metres. Edge steepness controls how abruptly the terrain drops at the polygon boundary — from a smooth slope to a near-vertical wall.
• Grade — samples the terrain elevation inside each polygon and flattens the terrain to that level, with a configurable edge blend width for smooth transitions.
• Object Distribution — scatters placed objects inside polygons or along lines. Configure spacing, random drift (jitter), edge buffer, and a numeric seed for reproducible results.
• Surface — marks vector polygons as ground surfaces. During export, surfaces instruct the game engine to treat the enclosed area as driveable or walkable terrain.
• Height Offset — raises or lowers features above or below the terrain surface by a fixed amount in metres.
• Numerize — assigns sequential numbers to features within the scoped layer or category. Runs once as a one-shot action.

Raster modifiers

The following modifiers work on raster layers:

• Rasterize — burns the shapes of vector polygons from a specified layer into this raster layer as pixel values. Runs once as a one-shot action. Currently supports editable grayscale rasters.
• Paint Lock Mask — prevents the Paint tool from overwriting areas covered by polygons in the specified vector layers. Useful for protecting boundaries or previously painted zones.

Terrain modifiers

The following modifiers work on terrain layers:

• Blur — applies a Gaussian smoothing pass to the entire terrain height map, softening sharp ridges and sculpt artefacts.
• Plateau — shifts the entire terrain surface up or down by a fixed metre offset, useful for calibrating the base elevation before other modifiers run.