Sculpt Masking

A mask protects part of the model from the sculpt brushes. Mask an eye, a hand or a finished area, and you can sculpt right up to it without touching it. Choose the Mask tool in the Sculpting tool row: the Mask controls then appear at the bottom of the sculpt palette, under the brush controls.

It is the same mask, and the same panel, as in Paint Masking. A mask made in Paint protects your sculpting, and a mask made here protects your painting. On a textured model, Paint keeps its mask per texel and Sculpt keeps it per point; switching modes carries the mask from one to the other. Coming back to Paint redraws only what you changed here, so Paint's finer detail survives elsewhere.

Making a mask

The row of icons at the top of the block chooses how a click or drag adds to the mask:

Tool	What it does
Mask Brush	Brush strokes protect (left mouse) or erase (Shift+left mouse) the mask. This is what is active whenever none of the shapes is armed.
Lasso Mask	Click the icon to arm it (this locks the camera), then drag a freeform outline with the left mouse button.
Box Mask	Click to arm, then drag a rectangle.
Circle Mask	Click to arm, then drag outward from the click point, which is the circle's centre. Hold Shift while dragging for a perfect circle.
Poly Mask	Click to arm, then click to place points, closing near the first point or with Enter.
Fill Mask (last icon)	Protects the whole mesh — the same as the Fill Mask button below.
SVG / Image Mask	Lays a vector drawing or a greyscale image as a mask, the way Alpha Drag works: drag it out, then move, scale and turn it with its handles or type its Width, Height and Angle in the panel, with its Strength. Nothing is masked until Enter, Space or Apply; Esc, Backspace, Delete or Drop throws it away and puts the tool away. Import SVG or Image... picks the file.

Click an armed shape's icon again to turn it off. An armed shape is outlined in yellow when it adds to the mask and in red when it subtracts.

Adding and subtracting with the shapes

Once a shape has been drawn it disarms, and a click is the Mask Brush again. The shape is still remembered, though: press Shift to arm it again for another shape that adds to the mask, or Ctrl to arm it for one that subtracts. Ctrl only works once something is masked; with nothing to subtract from, the status bar says so. Esc, Enter or Space drop the shape.

Face Select and Volume Select

These two buttons decide how deep the Lasso, Box, Poly and Circle masks reach:

Button	What it does
Face Select	The shape masks only what is actually visible to the camera.
Volume Select	The shape cuts straight through the model at every depth, including back faces and hidden geometry.

Angle Select and Color Select

Angle Select masks the connected surface that faces the same way as the polygon you click, within the angle you set. Tick Follow curves to follow a gradually curving surface however far it turns. Color Select masks the connected surface of a similar colour, within the Fuzziness you set. With both on, a polygon must pass both. While either is on, a click masks instead of sculpting. A click replaces the mask, Shift+click adds to it, and Ctrl+click removes from it. Turn the button off to sculpt with the Mask Brush again.

Select (Face) on voxel models

On a voxel model the block has one more tool, Select (Face). Click it to arm it, then click the model: the connected surface facing the same way as the point you clicked is masked. Shift+click adds, Ctrl+click removes. Click the button again to turn it off.

While it is armed, an angle slider (0–90 degrees) sets how far the surface may turn from the one you clicked and still be masked. Tick Follow curves to compare each triangle with its neighbour instead of with the one you clicked, so a gradually curving surface is masked however far it turns. Both are the Voxel tab's own settings, and the mask is the same one Voxel mode uses.

Changing the whole mask

Button	What it does
Clear Mask	Removes the whole mask.
Invert Mask	Swaps protected and unprotected everywhere, including partial, feathered values. Mask the part you care about, invert, then sculpt everything else.
Fill Mask	Protects the whole mesh — the usual way in when you want to carve one small region back out with the Mask Brush and an erase stroke.
Blur	Softens the mask's edge by averaging each vertex with its neighbours. A hard mask edge leaves a visible ridge in the sculpt; this is what removes it.
Sharpen	Tightens a soft mask edge back up — the inverse of Blur, for hard-surface work where a feathered boundary is wrong.
Grow	Expands the mask by one ring of vertices.
Shrink	Contracts the mask by one ring of vertices.
Mask from Selection	Turns the current polygon selection into the mask. Selection Tools can select by material and by connected region, so this is how you mask one material or one loose part without painting it by hand.

Every one of these can be undone with Ctrl+Z.

Seeing the mask

Masked areas are tinted in the viewport. Mask Opacity sets how strongly (0–1) — lower it to see the form underneath. The colour swatch beside it sets the tint colour; it is the same setting as the one in Settings > Interface, placed here so you can change it without leaving the mode. Both only change how the mask is shown; the mask itself is unchanged.

Memory slots

The clipboard button beside the colour swatch saves the mask to one of twelve memory slots, shown in the row beneath it. Click a slot's swatch to bring that mask back (undoable), or right-click it to delete it. These are the same twelve slots as in Paint, so a mask saved in one mode can be recalled in the other. In Sculpt the F1–F12 keys keep their Sculpt meaning, so click the swatch instead. A slot saved on one mesh cannot be recalled on another; the status line says so.