User Manual

On any round hole, the bore of a counterbore, or a sub-3 mm notch — features small enough that a twist drill on centreline is the right tool.

Pure centreline plunging, no orbiting. It rapids to clearance over the first hole, drops to feed height and plunges straight down. With a peck depth set, it bites that much, retracts to clear the chip, rapids back to just above the cut and repeats — clamping the final peck at the hole bottom. For a group of holes, one op covers all positions: lift, traverse at clearance, repeat.

On a hole or counterbore that must be opened up or finished to a target diameter larger than your end mill — counterbore recesses cleared to the flat floor, or pre-drilled holes sized to final.

Rapids to centre, plunges to the cut top, swings out on a tangent half-arc to the wall, then descends in full-revolution helical arcs until it reaches the bottom. It finishes with one flat full revolution to clean the wall and peels off on an opposite-handed lead-out so there is no witness mark. With more than one pass it cuts concentric helical rings at growing radii (a chip-clearance moat), finish pass at the wall by default.

On a cone cavity you want to machine with a normal end mill (flat, ball or bull nose) rather than a matched V-bit — usually because no matched V-bit exists, or the cone is too big to form in one plunge.

After approaching at the mouth (optionally on a quarter-arc lead-in), it runs a continuous helix whose radius shrinks linearly with depth — from the mouth radius to the tip radius — emitted as fine segments because a variable-radius spiral isn't a true arc. At the floor it cleans up with one full revolution and peels inward on a lead-out. Climb orbits CCW; conventional mirrors the whole path about the cone axis to flip to CW, gouge-safe.

On a cone cavity that a V-bit (or dedicated countersink) whose included angle matches the cone can form in one shot. The bit's own cone is the chamfer — no orbiting needed.

Pure centreline plunge, no horizontal cutting at all. It rapids to centre, drops to feed height and feeds straight down from mouth to tip — the V-bit flank cutting the cone in one shot. A peck depth breaks deep cones into bites with a chip-clearing lift between each; it exits by retracting off the floor.

This op is operator-authored, never an AFR suggestion — a plain drilled hole is not a thread, so the app will not speculate. You pick the hole's (or boss's) cylindrical face; the centre and Z extent come from the pick, the thread spec comes from you. Internally the tool orbits inside the hole at orbit radius = major radius − tool radius (the tooth reaches outward); externally it orbits outside the boss at major radius + tool radius. The helix direction follows the thread hand and the cut direction.

On any flat top face it can reach with a straight-down approach. Use it to true up the stock top or a raised boss to a clean reference surface.

One continuous rectangular spiral per Z level (not separate rings), laid over the face bbox plus the margin pad, with the cutter centre radius-compensated to reach the edges exactly. It steps down to the bottom; the first level enters by plunge or helix; climb winds CCW, conventional CW, alternating flips each level. With a finish pass on, roughing stops above the floor and a final full-face spiral skims it flat.

On any closed-wall cavity. The kernel auto-classifies it — fully walled, mixed (some edges open to void), or fully open — and switches entry/strategy accordingly.

Concentric offset rings inward from the boundary (discrete loops linked by feeds), stepped down to the floor. Fully-walled pockets descend on a helix around an interior anchor; mixed pockets plunge in the open-edge void; fully-open ones face outside-in entering on a lead-in arc from air. Islands are skirted at tool-radius + stock; with a finish pass on, a final ring cleans the floor.

On a closed cavity with straight or inward-drafting walls. This hogs out the whole volume.

Plunges near the centroid and walks concentric rings inset from the mouth (each wall offset by its own draft + tool radius + stock), so on a drafted pit each deeper level's footprint is smaller. With keep-tool-down on (default) it stays at depth and feeds to the next level rather than retracting, lifting only on the last level. Cut direction is alternating by default (fastest for roughing); a finish pass adds a clean floor ring.

On the walls of a pit, as the perimeter finishing pass that cleans up what Ramp Pocket left rough.

At each cumulative depth it walks one constant-Z ring — the mouth outline inset by that level's draft + tool radius + leftover stock — so on a drafted pit each ring sits progressively further in. It's one orbit per level (rings stack to trace the wall), not concentric clearing. Keep-tool-down (default) stays down between rings for continuous contact; a lead-in radius arcs tangentially onto each ring instead of plunging into the wall.

On a boss or plug standing up from the floor, with straight or drafted walls. This clears the surrounding air, not the plug.

Works the annular region between an outer clearance boundary and the plug, walking concentric rings stepped down to the floor. On a drafted plug the cross-section widens going down, so each deeper inner ring stands further off the plug. Keep-tool-down (default) links ring segments at depth — but only where a safe-region check confirms the path won't hit the plug or a neighbour. Neighbours can be passed as islands so rings clip at their edges; a finish pass cleans the floor.

On the walls of a raised plug, as the perimeter finish that cleans up what Plug Clear left rough.

At each depth it walks one constant-Z ring — the plug-top outline offset outward by that level's draft + tool radius + stock — so each deeper ring sits further out to follow the widening wall down to the base. (This is the mirror of the pit wall finish, which insets.) Keep-tool-down stays down between rings; a lead-in radius arcs onto each ring.

On a pocket with vertical walls whose floor is one tilted flat plane. The floor must tilt up — not vertical, not facing down.

Two phases. First a layered volume clear: concentric rings at each Z step, every layer clipped to where the tilted floor still sits below it, ring Z following the plane. Each fresh layer enters by plunge (default) or a clamped helix inside the cleared footprint; keep-tool-down feeds laterally between layers. Then an optional serpentine floor finish: scan lines along the constant-Z contour, Z tracking the plane.

On the recognised outer silhouette — the chord/polyline finish for the outside wall (straight segments only, no native arcs).

Buffers the outline outward by tool radius + stock and rides that ring, tool entirely in the void. Entry is one plunge per Z level at the start vertex, with a 90° tangent lead-in on the void side (auto-skipped to a straight plunge if its centre would land in material). It steps down one level at a time, one boundary ring per level unless you add outward gutter passes (walked outermost-first so the boundary stays the final clean pass).

When the outer silhouette carries true circular arcs (filleted corners, radius transitions) — the native-arc finish, real arcs instead of chords.

Walks the AFR arc chain segment-by-segment: each line and arc is offset by tool radius + stock to the cut side (the side is probed per-arc, not assumed), then consecutive offsets are trimmed to meet exactly at corners. Entry is a plunge at the chain start, with an opt-in tangent lead-in when Lead-in R > 0 (gouge-guarded). It steps down one level at a time, re-walking the chain each level. Single direction only — no alternating.

On a through-feature, slot, or irregular through-pocket — the chord/polyline inside finish.

Buffers the outline inward by tool radius + stock with Shapely (which safely collapses self-intersections) and rides that inner ring. One plunge per Z level with an opt-in lead-in arc; steps down one level at a time; with a stepover and ≥2 passes it adds inward gutter rings walked innermost-first so the boundary is the final clean pass.

When an inside profile carries true arcs — the native-arc through-feature finish.

Same arc kernel as the outside version but offset inward. With no operator pick it auto-starts at the widest spot of the feature so the lead-in and plunge get maximum room in a tight neck. The lead arcs are validated against the full tool-centre loop (not just the start point) so the arc body can't swing into the opposite wall; if it won't fit, it straight-plunges. Single direction only.

When you pick an open edge chain (first and last points differ) inside Inside/Outside Contour. Use it to machine one edge or an open profile rather than ring-walking an enclosed region.

No inside/outside — you pick the side. It one-sided-offsets the open polyline by tool radius + stock (left/right of travel, or on-line to engrave), emitting the offset centreline directly. Each depth pass plunges over the start, optionally swings a lead-in arc on the air side, walks the path, and lead-outs off the free end. Because the profile is open it cannot stay down between levels — every level retracts and re-plunges.

On a convex top-edge radius (an outside fillet along a pedestal or step) that a matched corner-round form tool can finish in one pass. Outside fillets only.

Walks the floor-edge polyline once at a single position, the corner-round profile seated on the convex edge — no angular stepping, no depth stepping. The form ground into the bit is the finished radius. Entry is a rapid to the start then a straight feed-plunge onto the edge; the edge is auto-extended by R at the ends so the corner sphere gets swept.

On any fillet edge — convex outside top radius or concave inside wall-floor radius. It is the only choice AFR offers for inside fillets.

Outside: the ball steps around the quarter-cylinder in angular increments (Stepdown deg (outside fillet)), passes linked as a zigzag; keep-tool-down feeds laterally between passes. Inside: a mesh-sliced Z-level finish over [floor, floor + R] — the mesh is sectioned at each Z, the cavity offset inward, and the cutter walks that closed contour up the concave radius.

On a beveled edge or V-groove whose angle matches a V-bit (chamfer bit) you have loaded — one centred tool scribes the whole bevel along the edge or groove vertex.

The V-bit plunges at the top-edge midpoint, then walks the edge; each successive pass interpolates a path further between the chamfer's top and bottom edge, stepping deeper into the face. Stepdown 0 = a single full-depth pass. Default cut direction is alternating (zigzag — shortest inter-pass link); keep-tool-down stays buried and steps over.

On a chamfer or V-groove cuttable with a standard end mill instead of a matched V-bit. One pass per wall; the kernel rejects cutters too wide to fit.

Walks the contact point down the bevel face in constant-Z passes (spacing = stepdown; 0 = one full-depth pass), offsetting the tool centreline off the contact path by a per-cutter (plan, Z) pair from the chamfer angle — so the flat corner of a square mill, or the tangent point of a ball/bull, rides the face while the body sits in air. Default alternating zigzag; keep-tool-down stays engaged between passes.

The kernel slices the whole part mesh at each Z Stepdown; the cuttable region at a level is everything inside the cut boundary that is not solid, shrunk by the tool radius plus wall stock. Concentric offset rings clear each region, entered by a climb-sense helical descent at a picked anchor (or a straight plunge into verified air when a helix will not fit). Because the region falls straight out of the mesh slice, drafted plugs, fillets and undercut overhangs are handled with no feature detection. Heights (Top/Bottom, default STOCK_TOP to MODEL_BOTTOM) scope the Z range; the Selection variant clips clearing to a picked footprint.

Instead of fixed-stepover rings, the engine grows a morphing spiral front: each pass rides at a distance from the already-cleared area that makes the radial cut width exactly the Optimal load everywhere it is free, and inserts trochoidal loops where corners would squeeze the width above it. Entry is a helical descent at the largest inscribed circle, with automatic plunge fallback; when the front pinches or splits, each remaining region gets its own fresh entry (wide regions) or medial-axis trochoidal slotting (thin necks). Climb-only by construction. A different strategy from 3D Pocket Clear — reach for it when you want full-flute depth in tough material.

The mesh is sliced at descending Z levels between Top and Bottom; at each level the cutter walks the wall contour (outside walls offset outward, holes offset inward) leaving a constant cusp on near-vertical faces. A built-in slope filter drops passes on undersides and overhangs, and every plunge/retract column is verified air before use. Passes are linked with gouge-gated hops (the tool lifts only as high as the surface between passes requires) instead of full retracts — a large air-time saving on multi-feature parts.

Straight passes at the stepover spacing sweep the part in X or Y; at every sample the tool is dropped onto the true surface contact, so the path follows floors, slopes and rides straight down walls in the same run (no steep-area exclusion). A tolerance-bounded fitter and a convex-corner clamp keep the emitted path within the Total tolerance band of the surface — lifting only, never cutting below it — and a stay-down linker orders and bridges the passes. Emission is native G2/G3 arcs by default, or pure G1 lines; the finish is identical either way, only the file changes.

The engine builds a signed-distance field of the part (OpenVDB), extracts the offset surface one ball radius out — the surface the tool CENTER rides when the tip touches the part — and slices that offset surface into rings spaced by the cusp-derived stepover. This is the production-CAM 3D-offset approach. Rings are ordered nearest-neighbour and chained; Z-ramp entries and tangent links are on by default. Surfaces steeper than the wall-angle limit are excluded — true verticals belong to Z-Level.

The kernel walks the mesh's face adjacency, keeping concave edges whose dihedral angle exceeds the Seam angle, chains them by tangent continuity, and places the cutter center on the seam bisector so the ball nests into the corner. Each chain gets its own plunge and lift; consecutive chains that end close together at the same Z are linked with a short stay-down hop instead of a full retract. Heights (Top/Bottom) scope coverage, same as Z-Level.

Ramp reuses the Z-Level core with a slope band: only wall segments whose surface slope falls inside [Slope from, Slope to] are kept (default 30-90 degrees, drafted-to-vertical), so floors and undersides stay untouched. Whole Part supplies the part outline automatically; Selection has you pick a closed edge chain in the viewport, and each Z slice is clipped to that footprint. Stepped mode cuts discrete Z passes bracketed by tangent lead arcs; Helical mode descends continuously across each revolution (first and last level stay stepped for a clean entry and flat floor). Passes are linked with gouge-gated hops by default.

You pick a profile face (its outer wire) or an edge chain under Feature Ops; the kernel walks that XY boundary once, raycasting each point onto the mesh so Z rides the true edge height, with surface-normal tool-radius compensation (the ball rides about one tool radius outside the wall). Horizontal stretches are refit into native G2/G3 arcs (0.01 mm chord tolerance); the rest stay G1. With a Stepdown set, the pass repeats down the wall from the varying top edge to the floor — and when Bottom is left at model bottom, each column stops at its own local underside instead of over-cutting thin sections. Industry names for this class: 3D contour finishing, boundary projection.

Pick the slot FLOOR face; the loaded disc cutter's neck rides in the existing clearance slot while the disc cuts the channel. Entry is STRICTLY LATERAL — the disc can never plunge (disc wider than neck). The op classifies the floor's walls: double-walled slots enter AXIALLY from an open end, descending to depth in air past the end face; single-walled slots use a SIDE lead-in from the open side; a blind far end is fed to a disc-radius short of it and backed out. Curved slots are followed along their centreline.

One kernel with T-Slot; the cross-section is purely the cutter's shape (flank angle comes from the tool's tip angle), so for a single pass the centreline sweep is identical. Same floor-pick, same wall classification, same axial / side lead-in entries, same blind refusal.

Centerline: the tool tip rides each picked chain (open trail or closed loop) at Depth below each chain point's own Z, so a chain on a non-planar edge engraves a uniform-depth groove along the surface. Line width comes from the tool tip, not the path: V tool width = tip flat + 2 × depth × tan(half angle); non-V tool width = tip diameter. The universal Stepdown row splits depth into passes (closed loops stay down and step at the loop seam; open trails retract and re-plunge). V Carve: pick letter FACES (one click brings the outline plus its islands) or closed edge loops; the V tool runs the region's medial axis, plunging until the cone spans wall to wall — narrow strokes cut shallow, wide strokes deep, branch tips run into corners at depth 0. Depth acts as the MAX-depth cap; the carve surface is the resolved heights Top. The same mechanism production CAM ships as an 'Engrave' toolpath.

The part is sliced along the rotary axis; at each axial level the part cross-section (grown by the cutter radius) is subtracted from the stock disc, and the remaining ring of material is cleared by a spiral comb: the tool enters at the stock skin and marches inward, each pass biting a fresh band of about one ring step until the innermost pass leaves a uniform wall stock. Every contour point becomes an (axial, radial, A) feed move; A is carried continuously so the table never spins the long way around, and the tool retracts to the safe radial between levels. The region math unions plane sections across the tool's full width, clips to what a radial tool can actually see (no cutting under overhangs), and checks every link corridor, hopping over material instead of feeding through it.

The part's outer radius over (axial position, angle) is treated as a height map, and everything above it is removed in shells. In Axial mode the tool runs along the rotary axis with A held static per pass, stepping A between passes for angular coverage and stepping radially for depth; Radial mode runs continuous-A, lathe-like passes around the axis instead. Every feed point sits at or above the part's outer surface at that spot, so the tip physically cannot reach inside the part — even on a leaky STL shell. The surface field is deliberately over-estimated (max-dilated) so keep-down links always block near material.

It is 3-axis Parallel wrapped onto the cylinder: the part is rayed once into a cylindrical contact buffer, then dilated by the ball with a closed-form formula so a late pickup (gouge) is impossible by construction. Passes are uniform-pitch rings or axial scans (industry-standard spacing), lightly smoothed inside a bounded tolerance tube that never crosses a real wall, then each run is fit with the same greedy line+arc engine as 3-axis Parallel — a fitted line is exactly one machine-frame move with zero chord error, and arcs are re-linearized on the fitted circle so raw scan noise never reaches the G-code. Emitted as G93 inverse-time coupled motion.

It walks the part's face adjacency to find concave edges, filters out tessellation noise below the Seam angle threshold, chains the seams into continuous runs, and then places the ball tangent to every face meeting at each point, emitting the tip along the seam. Because the cutter axis is locked to the radial direction on a 4-axis machine, a seam whose bisector tilts too far tangentially (worst case the wall-floor circle of a radial bore) cannot be cut without grazing the wall — those seams are rejected by the Reach tol gate rather than gouged.

You pick a flank (or a connected patch of faces) on a STEP part; the geodesic iso-contour engine lays evenly spaced passes over it, and each sample is posted to X, Y, Z and A so the surface normal is presented vertical in the machine's cross-section plane — output is G93 inverse-time coupled motion. A per-sample lean solve (within your Lean min/max) steers the tool around obstacles like the channel's opposite wall with zero-penetration against the whole solid as the hard constraint, preferring the Contact angle you set for surface speed. What the posture cannot reach is trimmed and reported, never silently kept.

The part is sliced with cylinders about the rotary axis at descending radius levels; at each level the op walks the exact iso-line where the ball just touches the part plus your Stock to leave — so a blade is an island the contour walks around, never an edge to cross. The tool stays through-axis (no lean solve, zero orientation freedom), a strategy class proven against a production-CAM reference toolpath. Every contour vertex is pinned to the true offset surface by an exact-distance solve, unreachable spots (overhung flanks, blocked reach) are trimmed and reported rather than silently kept, and every link between cuts travels a certified corridor. Heights Top and Bottom bound the radius ladder (they are tip radii, the Z-level Top/Bottom analogue).

For each hole: rapid to the safe radial at the hole's A angle, plunge radially in (a peck cycle when Peck depth > 0, one continuous plunge when 0), optional dwell at the bottom, rapid retract. Holes are ordered by a greedy shortest-A walk (sorted by axial and A, with A unwrapped to the nearest +/-360) so the table never rapids 359 degrees the long way round; the order is stable on the input, so after a tool break you can count holes by index. Breakthrough for through holes lives on the heights Bottom offset, not a knob.

Two motion strategies behind one op, deliberately BOTH offered and never collapsed: Static A rotates the hole under the spindle once, holds A, and orbits in clean G2/G3 arcs treating the cylinder wall as a flat tangent plane — the dimensional-truth choice for small bores. Helical A interpolates A with the axial axis so the tool follows the actual circle traced on the OD (emitted as short segments under G93 inverse-time) — the edge-quality choice when curvature dominates (large bores). Auto picks by chord error (roughly orbit radius / stock radius <= 1/8 stays static). With Pitch > 0 each orbit descends helically and closes with one flat finishing orbit; with pitch 0 it stepdown-levels with a straight plunge per level (good on a pre-drilled pilot). Batches share the shortest-A hole ordering.

Per radial pass from stock OD in toward the target: for each tab slot, plunge radially, feed a pure-A arc through the slot, lift, move to the next slot; then step the radius in by Stepdown. With Tabs = 0 each pass is one full revolution. Tab width is specified in mm of arc AT STOCK OD, so the physical tab is the same size regardless of part diameter. The cutter centre sits one tool radius on the air side of the parting plane, so the flute cuts exactly AT the boundary instead of straddling it. Because every feed move is a pure A move, the writer emits G93 inverse-time feed.

Approaches at one axial end at the safe radial, then helically descends by Stepdown while sweeping axially across the span, reverses at the opposite end, descends again, and serpentines until the target radius is reached; the retract spirals out if the exit end is open. Boundary handling per end: at a "wall" end the cutter centre stays a tool radius INSIDE the edge so the side flank cannot gouge the neighbouring full OD; at an "open" end it overtravels a tool radius so the bottom edge cleans the edge fully. The same op serves a step turn-down and full-OD facing — the difference is just which OD region you pick.

These transverse faces cannot be reached by the tool END, so the end mill FLANK finishes them: the cutter centre sits one tool radius (plus any stock to leave) onto the face's open side so the flank is flush with the face plane, then orbits at discrete radial levels from the face's outer material radius inward while the part rotates. Each orbit is CLIPPED to the real material at that radius via the recognised region polygon — a plain annulus gets full circles, a crank-web cheek gets arcs that follow the counterweight edge and skip the pin bore (islands are grown by a tool radius so the flank can't touch the pin).

Approaches one groove wall at the safe radial, helically descends in place at that wall by one Stepdown, sweeps axially at the new depth to the opposite wall, descends there, sweeps back — repeating until full depth, with a single retract at the end. Groove width is the detected axial span; depth runs from stock OD down to the groove floor (heights Bottom, seeded from the AFR-detected inner radius).

A slot and a pocket are the SAME geometry to the kernel: a closed perimeter on the unrolled cylinder, cleared radially level by level from the OD down to a floor — for a tube slot the floor is the stock ID, so the cut breaks through and there is nothing under the floor. Per level the cutter walks the offset perimeter with interpolated A that is re-projected per depth (a deeper cutter sits at a smaller radius, so the part rotates further to stay on the same physical wall). Cut mode (universal row) picks Helical continuous descent vs Stepped per-level passes; Keep tool down governs retracts in stepped mode.

Same kernel as Slot Clear — the only real difference is the floor: a solid pocket has material under it, so Clear floor defaults ON and the interior is spiralled out at each level. The perimeter walk uses interpolated A re-projected per radial level so the cutter stays on the physical walls as it descends; Cut mode (universal row) picks Helical continuous descent vs Stepped per-level passes.

Runs the pocket/slot clearing kernel's islands branch: the region to clear is the band around the picked plug out to the Clear offset, cleared radially level by level with the plug protected as an island. Because the plug stands through every level, the floor-finish / ring-direction machinery of the ordinary pocket does not apply here.

Per axial station and radial level, the tool makes a full-revolution A sweep while the tip rides the flat-end-mill radius-compensated silhouette of the pin circle — lifting over the pin and returning to the level on the far side (the classic "rotary pocket" strategy, but feature-driven). The cam is computed for an inflated pin (radius + stock to leave) so the leave is normal to the pin surface everywhere. One shared A grid serves every level, station and journal; descents and axial transits happen at the pin-down home angle, and rapids happen only at clearance. This op is the ROUGH: it leaves Stock to leave everywhere plus a lift-over scallop band (up to the stepdown) on the pin flanks — Eccentric Turn finishes the pin, Fillet finishes the cheek blends.

The tool axis follows the pin centre on the machine tangent axis while the tip rides the crown height, so the flat tool bottom stays tangent to the (allowance-inflated) pin at the point directly under the tool centre at every A. Over one revolution the contact point sweeps the ENTIRE pin circumference. The pass ladder starts at Stock allowance (what Clear by Feature left), descends by Pass depth to zero, then repeats Spring passes at zero — pass-major order with zig-zag station order. The shared A grid auto-refines until the orbit chord sag (which would undercut the crest) is below tolerance.

A ball-end tool rides the fillet arc while the A axis sweeps a full revolution per arc station; the ball centre sits inward along the surface normal so the ball is tangent to the fillet, and the toolpath carries the cutter TIP. The same kernel serves a coaxial fillet (a surface of revolution) and an ECCENTRIC fillet on an orbiting crank pin — the eccentric pose follows the pin centre via the same validated map the Eccentric Turn uses. The tool stays down marching between arc stations (a surface finish is continuous contact); rapids only at clearance; the eccentric A grid auto-refines until orbit chord sag is under tolerance.

Two tool models behind one Strategy knob. Form: a conical chamfer / spot tool whose flank matches the bevel angle rides the chamfer flush, one full A revolution per pass, with a radial ladder marching the tip from the shoulder end to the journal corner — standard chamfering, but the tool angle must match. Mill: a ball or bull nose end mill rides the cone face in Stepdown rings along the bevel (like the rotary Fillet but on a straight bevel) — any tool angle. Eccentric pins use the same validated pose map as the Eccentric Turn/Fillet so the tool follows the pin, not an epitrochoid; tool stays down between passes and rapids only at clearance.

The picked 3D polyline is unrolled to flat (axial, around-the-surface) coordinates upstream, then wrapped onto the cylinder as continuous interpolated-A motion, cutting from the surface radius down to the floor (heights Bottom) in Stepdown radial steps. Paths can be OPEN (an engraving stroke or edge trail) or CLOSED (a face outline / edge loop). Keep tool down (universal row) skips the lift between levels: open paths serpentine, plunging deeper at whichever end they finished; closed loops just plunge deeper at the joint. The rotary analogue of a 3-axis 2D contour.

Same manual pick as Wrapped Contour, but the closed region routes through the rotary pocket-clearing kernel: the perimeter is offset inward by the kernel itself and the recess is cleared level by level, interior spiralled out. Closed regions only. Cut mode (universal row) picks Helical continuous descent vs Stepped per-level passes, exactly as in Pocket Clear.