What modifiers are

A modifier is an operation attached to a target key. The target can be a layer, a category inside a layer, or a single feature. Saved modifiers live in project metadata as editorModifiers.

Most modifiers are persistent: they stay attached to the target and are reapplied when the Editor renders the project. Some actions are one-shot: they run once and write their result into layer or asset data.

Open modifiers with M or from the selected layer/category/feature controls. The available modifier types depend on the target kind: vector, raster, or terrain.

Modifier scoping

Modifiers can be scoped to three levels.

• Layer: applies to all compatible data in the layer.
• Category: applies only to features in one category inside a vector layer.
• Feature: 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 meters.
• Buffer: creates a filled area around a line or shape. Road workflows use buffered lines as road surface targets.
• Smooth: rounds sharp polygon or line corners using repeatable smoothing passes.
• Refine: cleans imported linework and can normalize intersections for roads, streams, and similar networks.
• Rectangulate: converts polygons into simple rectangular geometry. Useful for building footprints, but it can limit direct vertex editing because the rectangle is generated.
• Cut by bounds: trims geometry to a selected boundary role such as playable area or background zone.
• Classify: assigns categories from another vector layer by polygon overlap.
• Depth: carves terrain beneath polygon footprints, with edge steepness controlling the transition.
• Grade: samples terrain inside a polygon and flattens the footprint with an edge blend.
• Roadbed: smooths road height along lines and blends the road shoulder back into terrain. This pairs with road surface assignments in Road collections.
• Object Distribution: generates deterministic placement candidates inside polygons, along lines, or at points.
• Surface: renders polygons as terrain-following filled surfaces.
• Height Offset: raises or lowers terrain-following surfaces by a fixed amount.
• Numerize: writes sequential numeric attributes using a stable ordering method. This is a one-shot action.

Raster modifiers

The following modifiers work on raster layers:

• Rasterize: burns vector polygon attributes into an editable raster layer. This is a one-shot action and currently targets editable grayscale-style workflows.
• Paint Lock Mask: prevents the Paint tool from overwriting areas covered by selected vector polygons or buffered lines.

Terrain modifiers

The following modifiers work on terrain layers:

• Blur: applies smoothing to terrain height data, softening sharp ridges and sculpt artifacts.
• Plateau: shifts the terrain baseline by a fixed meter amount before other terrain shaping runs.

History and persistence

Modifier changes appear in the History panel alongside viewport edit history. Persistent modifier state is saved into project metadata after a debounce, while one-shot actions write their result immediately through the relevant layer or asset API path.

If a modifier changes generated placements or road overlays, the viewport recomputes those derived results from the saved project data. Reimporting vectors can clear modifier and placement metadata tied to the old vector layers.

Undo, autosave, and local-only state are explained in History and Saving.