Brush

The brush is for the parts of your map that don’t want to be a clean polygon — irregular shorelines, organic mounds, the beaten-down dirt path through a forest, the inside of a cave that needs a bit of texture beyond a flat region. It’s also the tool of choice for editing existing regions — paint a lower height over part of a tower to carve a window, or a higher height over part of a courtyard to raise a column.

Painting a stroke

1. In the inspector, switch to the Brush tab.
2. Set Height (the value to paint) and Radius (the brush size).
3. Click + Paint. The cursor turns into the brush reticle and the camera pan is paused.
4. Drag on the canvas to paint. The greyscale stamp follows your cursor.
5. Hold Shift while dragging to subtract — clears the brush’s contribution back to whatever’s underneath.
6. Press [ / ] to shrink / grow the brush radius live.
7. Press Esc or click Done painting in the panel to exit.

Every completed stroke (one drag, pointer-down to pointer-up) is committed when you release the mouse. Already-committed strokes survive when you exit — pressing Esc only ends the painting session, it doesn’t undo your work.

What “absolute” means

The brush is absolute, not additive. The value you paint is the height that area becomes — it doesn’t add to whatever’s underneath.

You have	You paint	Result
Empty area	h=+0.5	h=+0.5
Region at h=+0.7	h=+0.5	h=+0.5 (lowered)
Region at h=+0.7	h=+0.9	h=+0.9 (raised)
Region at h=+0.5	h=−0.4	h=−0.4 (carved into a depression)
Anywhere	Shift-drag	Brush contribution cleared; whatever’s underneath shows back through

So to “raise an area by 0.2”, you set the brush to the target height (e.g. 0.7 if the region was 0.5), not the delta.

Tip

A future “Raise / Lower” mode that does true delta editing is on the roadmap. Until then, glance at the underlying region’s height in the Polygon tab’s Regions list before you paint, then set the brush to where you want to land.

Carving depressions

Negative brush heights are the cleanest way to add irregularity to a flat region — wagon ruts, footprints, melted snow, bits of erosion.

1. Draw a region at, say, h=+0.4 for a raised dirt path.
2. Switch to the brush at h=−0.2 with radius 30 px.
3. Paint short strokes along the path’s length — each stroke creates a slight dip relative to the path’s surface.

The same technique with a positive brush gives you irregular high ground inside a region (rocks, debris piles).

Brush settings

Control	Range	What it does
Height	−1 to +1	The absolute height every pixel under the brush will become. Negative carves, positive raises.
Radius	4 to 512 px	The stamp’s radius in world pixels. Use [ and ] keys for live resize during painting.

There’s no falloff control on the brush — each stamp is a hard-edged circle. To get soft edges, paint with a smaller radius and shorter strokes; the rasterizer’s bilinear sampling at viewing time blends adjacent stamps.

Clearing the brush

The Clear all brush strokes button under the brush sliders wipes every stroke on this scene. It’s destructive and not undoable — use with care. (Regions and ramps are untouched.)

If you only want to clear part of the painting, switch to Subtract (Shift-drag) mode and paint over the bits you want to remove.

Performance

Brush strokes are stored as vector data (the path of points + radius + height) and snapshotted to a PNG that’s uploaded shortly after you stop painting. On reload, the snapshot is fetched once instead of replaying every stroke — so a heavily-painted scene loads in roughly the time it takes to grab one image.

If you’ve just painted a lot, expect a small delay (~1.5 seconds) before the snapshot uploads — that’s deliberate, so a flurry of strokes batches into one upload instead of one-per-stroke.

Exiting without losing work

There are three ways to exit the painting session, all non-destructive:

• Press Esc.
• Click Done painting in the amber banner at the top of the panel.
• Switch to a different tab (Polygon / Ramp).

Each completed stroke was already saved when you released the mouse. The “Cancel drawing” wording you’ll see on the Polygon and Ramp tabs becomes “Done painting” for the brush — that’s a deliberate cue that exiting is safe.

Tips

• Less is more. A few well-placed strokes beat a coverage pattern. The eye picks up “this area has a bit of bumpiness” much faster than “this area is fully detailed.”
• Smaller radius for detail, larger for areas. A 200 px brush for filling a depression in a region; a 30 px brush for the ruts inside it.
• Combine with falloff regions. Paint the broad strokes with a region (with falloff for soft edges), then add detail with the brush.
• The 3D preview shows brush detail clearly. When you can’t tell if a stroke is doing what you want, open the 3D modal and rotate.

Related

• Drawing regions — for the broad areas you’ll then detail with the brush.
• Ramps — for slopes the brush can’t easily approximate.
• Parallax & preview — global controls, the 3D modal, and what to do when something looks off.