Paint Masking & Memory Slots

A mask protects part of the surface: strokes simply stop at its edge, so you can paint boldly up to a boundary without touching what's on the other side. Masked texels stay untouched in every enabled channel at once, and partial protection is honored too — a feathered mask edge lets a proportionally weakened stroke through. It works on the Loaded Mesh and on the Generated Mesh, and it is the same mask the Sculpt brushes obey (see below).

One mask for Paint and Sculpt

A mask made in Paint is there when you switch to Sculpt, and a mask made in Sculpt is there when you come back to Paint. Both modes show the same Mask panel, with the same tools in the same order, so everything on this page also works in Sculpt Masking.

Paint can protect detail finer than the mesh: on a textured model its mask is stored per texel, while Sculpt's is stored per point. Switching modes carries the mask across:

• Paint to Sculpt — each point takes the mask under it. Paint's own mask is kept exactly as it was.
• Sculpt to Paint — only the parts you changed in Sculpt are redrawn into the texture mask, as fine as the mesh's points. Everything else keeps Paint's own detail, such as the crisp edge of an SVG mask.

When you paint the Generated Mesh's textures, the mask lives on its points, just as it does in Sculpt. The brush, the shapes and the buttons all edit those points, and texture painting stops wherever they are masked. On a coarse Generated Mesh, that makes a mask's edge as soft as the spacing of its points.

The Mask panel

Click the Mask icon in the Painting tool row to open the Mask panel. It is a toggle, not a tool: opening it does not change which brush you are holding, so the panel's Clear/Invert/Fill buttons stay within reach while you keep painting. Closing the panel while one of its own mask tools is still selected drops you back to the Paint Brush, so a leftover click can't silently keep masking with no panel on screen to explain it.

Building a mask

The panel's tool row, left to right:

• Paint Mask — a brush that paints protection directly, for freehand or feathered boundaries. Left-drag adds protection, right-drag erases it. Radius, falloff and strength come from the ordinary brush controls.
• Lasso Mask — drag a freeform outline; everything inside becomes protected when you release.
• Box Mask — drag a rectangle from corner to corner.
• Circle Mask — drag outward from the click point, which becomes the circle's center. Hold Shift while dragging for a perfect circle instead of an ellipse.
• Poly Mask — click to place corner points; close the outline by clicking near the first point or pressing Enter.
• Fill Mask — a one-shot action, not a tool: one click protects the entire mesh. Useful as a starting point when it's faster to unmask the part you want to paint. The same action is offered as a text button lower in the panel.

Under the tool row, SVG / Image Mask lays a vector drawing or a greyscale image as a mask. It works like Alpha Drag: drag it out on the model, and nothing is masked yet. While it is placed, move, scale, stretch and turn it with its handles, or type its Width, Height and Angle in the panel; set its Strength (how far it masks) there too. Enter, Space or Apply masks what it covers. Esc, Backspace, Delete or Drop throws it away and puts the tool away. Holding Ctrl while you turn it keeps it upright. Import a new file with Import SVG or Image....

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. A click replaces the mask, Shift+click adds to it, and Ctrl+click removes from it.

Arming, camera lock, add vs. erase

Selecting Lasso, Box, Circle or Poly arms the tool and locks the camera, so the next drag draws the gesture instead of orbiting. When the gesture completes, the tool disarms — a stray drag can't add another region by accident. From there:

• Shift re-arms the same tool to add another region (gold border on its icon);
• Ctrl re-arms it to erase — the gesture removes protection instead of adding it (red border);
• Esc, Enter or Space exits back to the Paint Brush, as does re-clicking the tool's icon.

Face Select vs. Volume Select

Two buttons under the tool row decide how deep a Lasso/Box/Circle/Poly gesture cuts. Face Select (default) only affects surfaces actually visible to the camera. Volume Select cuts straight through the model at every depth — back faces and hidden geometry included — which is what you want when masking a whole limb or panel in one gesture. This is the mask's own setting, separate from the identically-named toggle in Selection Tools.

Whole-mask actions

• Clear Mask — removes all protection everywhere.
• Invert Mask — swaps protected and unprotected everywhere, including partial/feathered values. Mask the part you want to keep, invert, and paint the rest.
• Fill Mask — protects the whole mesh (same action as the tool-row icon).
• Blur / Sharpen — softens the mask's edge, or tightens a soft edge back up.
• Grow / Shrink — expands or contracts the mask. On a texture mask each press moves the edge a few texels, more on a larger texture. On points it moves the edge one ring of points.
• Mask from Selection — turns the current polygon selection into the mask. Use it to mask one material or one loose part that Selection Tools selected for you.

On a texture mask, Blur, Sharpen, Grow and Shrink work within each UV island, so an island's edge is not pulled toward the empty space around it. They do not cross a UV seam. To grow a mask across a seam, switch to Sculpt, grow it there on the points, and come back.

Mask Opacity (0–1, default 0.5) controls only how opaque the viewport overlay renders — lower it to see the surface underneath. It never changes the mask itself. While the mask is on points, the opacity and colour are the points' overlay, the same ones Sculpt uses.

Undo

Every action that edits the mask is undoable: Paint Mask strokes, right-click erasing, each shape, Angle and Color Select, every button in the panel, and recalling a memory slot all step back with Ctrl+Z (and forward with Ctrl+Shift+Z). The memory slots themselves are the exception: saving into a slot or deleting one edits the stored bank, not the live mask, and is not undoable.

Right-click erases the mask — from any brush

Once any mask exists, a right-click drag with the regular paint brushes erases mask protection under the cursor, using the current brush size and falloff — no need to switch to the Paint Mask tool just to nibble a boundary back. The stroke lands on the undo stack like any other mask edit. (While the Stencil overlay is active, right-drag pans the stencil instead — the stencil takes precedence.)

The mask color

New protection is tagged with the color shown in the swatch next to Mask Opacity, and the viewport overlay renders each region in the color it was painted with — so two masks built in different colors stay visually distinct. Picking a new color clears the live canvas to start the next mask fresh; if the mask you were on is already saved to a memory slot, the panel moves to the next empty slot first so the saved one is not disturbed.

Memory slots

Twelve fixed slots store masks for instant recall — build a mask once for each panel, decal region or material boundary, then flip between them as you work. The row under Mask Opacity always shows all twelve: a saved slot draws as a swatch of its mask's color, an empty one as a plain F1–F12 placeholder, and the slot you are currently working against carries a gold border.

• Save — click the clipboard button beside the color swatch. It saves into the slot you are already linked to (re-saving updates it in place), or the first empty slot otherwise. If all twelve are full, the status line says so — delete one first.
• Recall — click a saved slot's swatch, or press its F1–F12 key while in Painting mode. The slot's mask replaces the live one (undoable). An empty slot's F-key does nothing. Outside Painting mode the F-keys keep their other meaning — Selection Tools' color groups.
• Delete — right-click a saved slot and choose Delete.

The slots work in Sculpt too, through the same row in its Mask panel; there the F1–F12 keys keep their Sculpt meaning, so click the swatch instead. A slot keeps the mask in the form it was saved in: per texel from Paint on the Loaded Mesh's textures, per point anywhere else. Recalling it where the other form is shown converts it, just as switching modes does. A slot saved on one mesh cannot be recalled on another; the status line says so. Once you have saved into a slot, it follows your later strokes, shapes and clicks, until you pick another slot.