Drawing, erasing and painting

The three tools

Tool	Key	Click	Shift + click	Ctrl + click
Attach	D	Add	Erase	Paint
Erase	E	Erase	Add	Paint
Paint	R / P	Paint with the primary colour	Paint with the secondary colour	Add

Every tool also has:

Chord	Does
Alt + click	Pick the colour under the cursor (eyedropper)
Shift + Alt + click	Draw on the grid’s floor and walls, even over empty space
Ctrl + Alt + click	Switch to editing the model under the cursor

The hover cube tells you what a click will do before you click. It’s white for add, red for erase (a whole red box when you drag), and the swatch colour for paint. Erase and Paint only touch voxels that exist, so a drag over empty space never promises anything it can’t do.

The five brush shapes

Switch with the number keys while any voxel tool is active, or in Voxel Mode ▸ Brush:

1. The five brush shapes.
2. Lock To Plane and Match Colour (and Fill Grid Sides for the Face brush).
3. Mirror on X, Y and Z.
4. Snap To Voxel Grid, and Align To Voxel Grid for models already out of place.

1 Voxel

One voxel per cell the cursor crosses. Drag for a freehand trail.

2 Face

The most useful brush. Press on a face and drag along its normal.

• Dragging away from the model stacks a layer per voxel of movement.
• Dragging back peels layers off again, and past the original surface it carves into the model.
• With Erase, it works the other way round.

What counts as “the face” is the flat region under the cursor:

• Match Colour on (the default): only the connected, single-coloured flat area. Use colours to mark out parts and the brush respects them.
• Match Colour off: the whole flat layer, whatever its colours.

Either way, a hole or a covered face stops the spread.

Fill Grid Sides (off by default) lets a Face click that misses the model use the grid’s floor, walls and ceiling as a face. One click lays a floor, and one drag builds a slab. It’s off because a near miss would otherwise add a whole side.

3 Box

Drag a rectangle from corner to corner. To give it depth, tap X, Y or Z mid-drag (see axis locks) and keep moving. A box erase can start in empty space, dragged from a corner in the air.

4 Line

A straight line from press to release. Hold Shift while dragging to pin it to the single axis you are pulling along.

5 Shape

Any shape in the Voxel Library becomes the brush tip, stamped along the drag. The tip is a silhouette: it paints in your active colour, not the shape’s own colours. Set it in Brush ▸ Shape, or right-click any shape in the library and choose Draw With ….

Setting	Meaning
Size	Edge length a built-in tip is generated at
Fit To Size	Scale a saved shape so its longest side matches Size
Spacing	How many voxels the cursor travels before it stamps again

The Brushes category of the library holds tips made for this: chisel, cross, plus and others.

Typing an exact count

Mid-stroke, type a number. It means how many voxels:

Brush	The number counts
Face	Layers. Press on a face, type 5, get five layers.
Voxel	Voxels along the drag direction, with the run in between filled
Line, Box	How far it reaches along the drag

Backspace deletes a digit, - flips the direction (on a face: carve instead of build), and Enter confirms without releasing the mouse. You can type before moving the mouse: the direction then comes from the face you clicked.

Locking a stroke to an axis

While dragging, tap X, Y or Z and the stroke moves only along that axis, from where the drag is now. Tap it again to let go, or tap another axis to switch. Drag a trail, tap Z, and the column carries on straight up.

A locked axis overrides Lock To Plane while it is held. Dragging past the grid edge clamps to the wall rather than stopping.

Lock To Plane

On by default. A drag stays on the plane of the face it started on, instead of climbing up the voxels it is drawing. It only applies when the stroke starts on a face.

Mirroring

Mirror X / Y / Z in the Brush panel (or the pie, Shift + Alt + S) repeat every stroke across the middle of the grid on that axis. Turn on several for two- or four-way symmetry.

Undo

Ctrl + Z and Ctrl + Shift + Z. A stroke, however long, is one step. These keys work wherever the mouse is, over the sidebar included. The Voxel Mode panel also has Undo and Redo buttons.

Fast drags

The mouse reports its position only so many times a second. When you drag fast, Voxel Mode fills the gap between two samples, so a quick stroke is a continuous line and not a dotted one.