Sculpt Stroke
The tool that deforms the points of strokes you have already drawn, in the viewport or into depth.
Reference
- Tool
- Sculpt Stroke
- Panel
- Tool Options
- Section
- Sculpt
The Sculpt Stroke tool moves the points of marks that already exist. It does not paint and it does not build relief: it takes the strokes baked on the active layer and pushes their points around under the pen, the way a modelling tool pushes vertices.
It acts on every stroke on the whole layer, paint layers included, and by default it works in the viewport — the drag you make on screen is the drag the points receive. A toggle promotes it to work in depth instead. The tool's footer states the plain case directly: "Sculpts every stroke on the whole layer (paint layers too), in the viewport — drag over the art."
Sub-tools
Five brushes ship. They are chosen from the Brush picker in Tool Options; the Brush Settings panel carries only the hint "Brush and falloff are in Tool Options."
Grab
Each point under the brush translates by the pen's delta, scaled by its falloff weight. It is a pure 1:1 drag — the only brush with no strength, because there is nothing to modulate. Use it to reposition a line rather than to change its character.
Smooth
Each interior point moves toward the midpoint of its two neighbours, by weight × strength. The two endpoints never move, so relaxing jitter out of a line cannot shorten it or pull its ends inward. The stroke needs at least three points.
Pinch
Every point under the brush moves toward the brush centre by weight × strength. It gathers a line into the pen rather than smoothing it — neighbours are irrelevant, only distance from the centre matters.
Inflate
The same kernel as Pinch with the strength negated: points move away from the brush centre. Pinch and Inflate are one mechanism in two directions.
Flatten
Computes the mean position of every point carrying weight, then pulls each of those points toward that average by weight × strength. Where Smooth is local — each point sees only its two neighbours — Flatten is regional: the whole weighted set converges on one shared centre.
Falloff
Falloff decides how a point's distance from the brush centre becomes its weight. Distance is normalised so that t = 1 at the centre and t = 0 at the rim; a point outside the radius has weight zero. Six curves ship, and this picker belongs to Sculpt Stroke alone.
| Curve | Shape | Character |
|---|---|---|
| Smooth | t·t·(3 − 2t) — smoothstep | Soft in and out. The default. |
| Sphere | √(1 − (1−t)²) | Rounded and domed — near-full weight across most of the brush, falling away steeply at the rim. |
| Sharp | t² | Concentrated at the centre, falling away quickly. |
| Root | √t | Wide, with a soft edge — the inverse bias of Sharp. |
| Linear | t | An even ramp from centre to rim. |
| Constant | 1 everywhere inside the radius | A hard round brush; no feather at all. |
3D space
With 3D space (push into depth) on, the brushes stop working in the view plane and act in world space. Orbit with two fingers to see the result.
The displacement scales with the brush's on-screen size, so the feel does not change as the camera moves. Each brush interprets depth differently:
| Brush | Behaviour with 3D space on |
|---|---|
| Grab | Unchanged — it stays a view-plane drag. |
| Inflate | Pushes the ink out of the plane it was drawn on, along the stroke's normal. |
| Pinch | The same push along the negated normal — into the plane. |
| Smooth | Relaxes each point toward its neighbours' midpoint in world space. |
| Flatten | Pulls the points onto a mean plane through their centroid. |
A flat stroke's points are stored as 2D coordinates on the surface they were drawn on, so a displacement along the normal is not representable at all. The first 3D sculpt therefore promotes the stroke to a world-space tube. The promotion is visually a no-op — nothing appears to happen until the next dab moves it. As the footer puts it: "Flat strokes become 3D strokes the first time you sculpt them."
Two behaviours follow from working in depth. Points further from the eye than the front-most stroke under the cursor are left untouched, so the brush cannot reach through a near surface and disturb a wall behind it. And a fill is treated as a surface: its triangles are pushed directly rather than the boundary loop being re-triangulated.
Promotion requires a flat source surface
Only a stroke whose frozen surface is flat can be promoted into depth. A stroke drawn on a bent grid — a cylinder, sphere or cone — cannot be promoted, so 3D space has no effect on it. The brush appears to work and nothing moves. Sculpt such strokes with 3D space off, or draw them on a flat grid if you intend to displace them later.
Options
Sculpt Stroke's controls live in Tool Options, under the Sculpt section.
The brush radius. The scale is logarithmic, so the low end — where a few points of radius is the whole difference between nudging one point and moving a limb — gets as much travel as the high end. Sculpt Stroke and Sculpt 3D share one size value, so changing it here changes it there.
Grab · Smooth · Pinch · Inflate · Flatten.
Smooth · Sphere · Sharp · Root · Linear · Constant.
How far toward its target a fully-weighted point travels per dab. Displayed as a percentage. Shown only when the brush is not Grab — Grab is a 1:1 drag and has no strength.
Switches the brushes from the view plane to world space, as described above.