Brush tree: target r2 (representation per hull, the hand cage as the measuring stick)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/brush-tree-target.md

@@ -1,256 +1,148 @@
-# Brush tree: target
+# Brush tree: target (r2)
 
-Campaign `brush-tree`, area geometry, owned by the Aetheria/Ghostlight Self
-(`aetheria-release:ruling:brokkr-ctl-job-to-ag-self`). Drafted by Imagination
-(`imagination-brush-tree-target`, session `self-2026-10-10-ag2`) on 2026-10-10.
-This is step 0: the ends, not the means. It contains no cut plan.
+Campaign `brush-tree`, owned by the Aetheria/Ghostlight Self. Drafted by Imagination
+(`imagination-brush-tree-target-r2`, session `self-2026-10-11-ag2`) on 2026-10-12.
+It supersedes r1 (`49948c8b`, the CSG-only target). This page holds the ends, not the means:
+no cut plan. The typed `brush-tree:target:r2` holds the invariants, the not-in-scope list and the
+canonical implementations; this page holds why, and the numbers behind the bars.
 
-- **Title:** Brush tree: OpenSCAD-shaped CSG trees authored in Blender through `brokkr-ctl`.
-- **Repos:** `GameCult/GameCult.Geometry.Csg` (the truth and the kernel),
-  `GameCult/Brokkr` (the agent's hands in Blender), `GameCult/Aetheria`
-  (the first consumer), and `GameCult/CultLib`, only if a ruling sends work
-  there (the cultcache-py directory store, Q `blender-transport`).
-  All four remotes are GitHub today; Aetheria moves to Forgejo under
-  `aetheria-release:ruling:forgejo-primary-github-mirror`.
-- **Working branch:** `eureka/brush-tree` in each repo it touches.
-- **This document's home:** `GameCult.Geometry.Csg/docs/brush-tree-target.md`.
-  The crate owns the truth the campaign builds, and two of the four research
-  passes already live beside it in `docs/research/`.
+- **Repos:** `GameCult/GameCult.Geometry.Csg` (the tree, the field, the kernel, the scorer),
+  `GameCult/Brokkr` (the agent's hands in Blender), `GameCult/Aetheria` (the first consumer).
+- **Working branch:** `eureka/brush-tree`.
 
-## Rationale
+## The rulings this target rests on
 
-The operator rebuilds Tripo-generated hard-surface hulls by hand: retopology,
-seams and bevels, at about 30 minutes per part. The campaign replaces that with
-a collaborative loop in Blender. The work is split by what each party does
-well:
+Read them in the mind by id; their operator quotes are the authority, not this page.
 
-- **The operator** points at part of the messy hull, using her Edit Mode
-  selection plus the viewport framing.
-- **The model** proposes a parametric form, or builds the one she names ("these
-  pipes are tubes", "a sphere, solidified, with a prism cut out"). It does the
-  naming, grouping, symmetry and composition.
-- **A classical fitter** does the numbers: least-squares or RANSAC primitive
-  fitting, plus GlobFit-style relations.
-- **Feedback** is a deviation heatmap plus a viewport render, iterated.
+- `brush-tree:ruling:representation-per-hull`: subdivision limit surfaces for continuous bodies like
+  Dexter Quiet, primitives for mechanical hulls like the squatter mech ship; both paths, per hull or
+  per part. It narrows the "mesh CSG is the main representation" clause of
+  `settled-direction-2026-10-10` to mechanical hulls.
+- `brush-tree:ruling:pursue-sdf-composition-remeshing`: the continuous path is an SDF composition
+  remeshed automatically; viability rests on the remesher; the operator's own Dexter Quiet rebuild is
+  the reference it is measured against.
+- `brush-tree:ruling:shippable-part-bar`: clean unbroken flow, part-coherent low-distortion UVs,
+  one-segment bevels with face-weighted normals.
+- `brush-tree:ruling:no-unownable-tools-in-loop`: only code we can own is in the loop.
+- `brush-tree:ruling:spike-sdf-smin-to-cage`, `:spike-instant-meshes-field-features`: the spikes
+  whose results (runs 4 and 7) this target reads.
+- Unchanged from r1 and still in force: `openscad-target`, `brokkr-beats-blender-mcp`, `cli-not-mcp`,
+  and the defaulted rulings on the Blender sink, `run`, docs lookup, look files, the per-ship tree
+  `.cc`, persistence through cultcache-rs, the Package path, Studio and impostors.
 
-The output is a typed CSG brush tree. From that one tree come the lowered mesh,
-its UVs, its topology near cuts and its microbevels.
+## What changed from r1, in one paragraph
 
-Why this shape, by the evidence:
+r1 lowered every hull through mesh CSG with field-derived microbevels. The probes showed CSG cannot
+build Dexter Quiet's continuous curvature (run 2), and the operator ruled the representation per hull.
+A hand-designed cage (run 3, v7: chamfer 0.228 %) beat every automated route; SDF composition with
+smooth-min fuses the body and its sweeps "without breaking a sweat" (run 4) but its program fidelity
+(0.52 %) and the remeshers' flow (runs 5-7: open field loops, 38-69 poles per 1000 vertices, UV area
+distortion 6-10x the designed cage's) fall short. Run 7 also found that the fidelity wall belonged to
+the SDF program, not the remesher: measured against the SDF itself, every remesh sat at 0.01-0.07 %.
+Microbevels from the field are gone: the bar names one-segment mesh bevels.
 
-- **Model fluency.** CAD-Recode and MeshCoder emit code (CadQuery, Blender
-  Python) precisely because language models write code fluently
-  (CultLib `docs/research/inverse-procedural-modelling-prior-art.md` §1,
-  6bdc23c9). OpenSCAD is a CSG tree written as text, with a large public
-  corpus.
-- **Text-only loops fall short.** BlenderGym shows the best VLM still far
-  behind humans on geometry editing (Chamfer 1.120 vs 0.334, same doc §4).
-  BenchCAD reports single-literal errors at high IoU. That is why numbers go to
-  a fitter and judgement goes to the model and the operator, not to unaided
-  generation.
-- **Failure without coherence.** VibeGeometry's recorded failure was "local
-  plausibility without global coherence" (same doc §0b). The defence here is a
-  typed tree with one owner, scored against the target by one distance function.
-- **Brushes are the durable design surface.** The crate's own doctrine says "the
-  brush tree is the authority; the mesh is cache and evidence"
-  (`docs/realtime-csg-doctrine.md`, Core Model). This campaign makes that true
-  of persisted state, not only of the in-memory assembler.
-- **The bar is the Blender MCP servers, and Brokkr exceeds it.** They offer
-  viewport sight, code execution and API docs, but none reads selected Edit Mode
-  geometry, and none has auth or admission (Brokkr
-  `docs/research/blender-mcp-capability-bar.md` §A(b), §B(b), f97d4dc). Brokkr
-  already has typed intents, receipts and admission on its Unity side
-  (`docs/provider-contract.md`, Admission).
+## What the pipeline turns a brush tree into
 
-## Body facts the target rests on (probed 2026-10-10)
+**The tree** is one typed document per ship (`tree-store-per-ship-cc`): primitives, transforms,
+scoped booleans, and smooth unions with a named radius. Every part (top-level branch) declares its
+representation, `field` or `kernel`. The declaration is authored, never inferred from the shape.
 
-- **GameCult.Geometry.Csg** (main at `5b5dc34`):
-  - Five primitives: Box, OrientedBox, CylinderZ, DomeCapZ, FloretArm (`src/brush.rs`).
-  - The polygon kernel runs CSG only for Box and OrientedBox cutters. It skips
-    other cutters with `SubtractIgnoredForNonBox` / `IntersectIgnoredForNonBox`
-    (`src/assembler.rs` ~803, ~836).
-  - The assembler and `field.rs` consume one flat ordered stream in which
-    Intersect is global. `CsgTree` branches exist in `src/tree.rs`, but the
-    assembler does not honour them as scoped nodes.
-  - `field.rs` lowers the stream to a signed-distance bound for every op on
-    every primitive. It has no smooth blend.
-  - `TriangleMesh` gives every quad 0-1 UVs. It carries per-triangle material
-    only: no brush id, surface id, smoothing or tangent (`src/mesh.rs`).
-  - `Brush` and `Primitive` derive no serde.
-  - The "CultCache records" in `src/cult_geometry.rs` are `rmp_serde`
-    msgpack tuples with schema-string constants. They are not written through
-    CultLib's `cultcache-rs`, and no record holds brushes.
-- **Brokkr** (main at `f97d4dc`):
-  - The Blender add-on admits eight object-level commands
-    (`surfaces/blender/brokkr_bridge/blender_target.py:402-423`). Its snapshot
-    reports mesh counts only (`:568-575`). It has no render, no mesh read, no
-    Edit Mode read and no code execution.
-  - Its store is the cultcache-py single-file store. cultcache-py has no
-    directory store (`CultLib/packages/cultcache-py/src/cultcache_py/stores.py:22,85`).
-  - Its optional CultNet server binds 127.0.0.1 with no auth token
-    (`blender_target.py:288-350`).
-  - `brokkr-command` is a .NET, Unity-only caller (`brokkr-command/Program.cs`).
-    `brokkr-ctl` does not exist.
-  - The Unity side's rulings F4 to F6 settle a file transport, a sink that is
-    off by default, and single-use command ids
-    (`docs/brokkr-adoption-cut.md`, Rulings).
-- **CultMath:** `BoundedLeastSquares` exists in C#
-  (`CultLib/packages/cultmath/src/CultMath/BoundedLeastSquares.cs`).
-- **Mesh probe:** the probe running under rulings `mesh-probe-exploit-not-measure`
-  and `mesh-probe-both-vocabularies` has not written `run1/RESULT.md` yet.
-  Its scratch `demo-hull.scad` already shows the model reaching for top-level
-  variables, `module`, `hull()`, `minkowski()`, `polyhedron`, `mirror` and
-  `cylinder(r1, r2)`.
+**A `field` part** (continuous body, Dexter Quiet):
 
-## Design truths the campaign produces
+1. Field: the part's signed-distance program, every primitive and blend defined once in Geometry.Csg.
+   Hard edges the author wants crisp are declared as creases (a hard `max`, run 4's wing rim), not
+   detected afterwards.
+2. Cage: a coarse quad-dominant control cage whose crease edges lie on the declared creases and form
+   closed loops, refit so its Catmull-Clark limit surface lies on the field's zero set (run 4's refit,
+   run 3's least-squares in a mirror-reduced space).
+3. Evaluated mesh: the operator's own stack, Mirror, Subdivision (limit surface), Bevel (one segment,
+   on the creases), Weighted Normal (`dexter-quiet-cage/README.md`). Seams lie on the closed crease
+   loops and part boundaries; run 7 showed seams through a broken crease join wing top and bottom.
+4. Output: the cage with its stack, as an object in the ship's `.blend`; Package applies and exports it.
 
-1. Each hull rebuilt through the loop exists as one typed brush-tree document in
-   CultCache. Everything else is derived from it: text, mesh, UVs, bevels,
-   heatmap, projections into Blender.
-2. The model reads and writes that tree as OpenSCAD-shaped text. The operator
-   reads and writes it through Blender. Both edits land through one commit path.
-3. An agent drives Blender with `brokkr-ctl blender look | selection | fit
-   <primitive> | run <script>`. Every call is a typed, admitted Brokkr intent
-   with a receipt, and `--help` is the schema.
-4. Geometry.Csg lowers the tree to a mesh whose faces know their brush and
-   surface. The mesh carries the UVs and seams the brushes declare, and smooth
-   microbevels at cuts derived from the same tree's field.
-5. Aetheria receives the lowered hull through its existing ship pipeline.
+**A `kernel` part** (mechanical, the squatter mech ship): the polygon kernel builds exact planar faces
+with scoped booleans, a one-segment bevel on hard edges, face-weighted normals, and UVs from each
+brush's declared charts. The r1 kernel machinery and its open questions serve this path.
 
-## Invariants
+**Both** reach Aetheria the same way (`lowered-hull-through-package`): an object in the ship file,
+exported by the existing Package. Nothing reads a cage, mesh or render back as truth.
 
-- **I1. One truth.** The typed CultCache brush tree is the only authority for a
-  hull's shape, surfaces and structure. OpenSCAD-shaped text, Blender objects,
-  meshes, fields, heatmaps and impostors are derived. None of them is read back
-  as truth except through I3.
-- **I2. Text is a surface, not a store.** The OpenSCAD-shaped syntax is an
-  authoring and lowering surface. A tree prints to text deterministically.
-  Printing a tree and parsing it back yields the same tree (round-trip). Any
-  text the parser accepts, which also renders in OpenSCAD, means the same solid
-  in both. Where our extensions add surface data, OpenSCAD ignores it and still
-  renders the same solid.
-- **I3. One commit primitive.** Every change to a tree goes through one commit
-  that names the revision it was based on. That covers parsed text, an operator
-  edit in Blender, an accepted fit and a scripted change. A stale base is
-  refused, never merged silently. No second writer exists: no Blender-side
-  cache, no CLI-side tree and no daemon copy.
-- **I4. One distance per primitive.** Each primitive's signed distance is
-  defined once, in Geometry.Csg. The fit residual, the deviation heatmap, the
-  microbevel blend and field-based scoring all evaluate that one definition. A
-  fitter that minimised a different distance would fit a shape the kernel does
-  not build.
-- **I5. No silent skips.** Every primitive and operation the authoring surface
-  accepts is honoured by every lowering that claims to build the tree: the
-  polygon kernel and the field. Anything a lowering cannot honour is refused at
-  parse or commit, never dropped with a warning.
-- **I6. The tree is a tree.** A branch's operation applies to its children only.
-  Nested `difference` inside `union` means what OpenSCAD means by it. The flat
-  global-Intersect stream may survive as an internal lowering, but it cannot
-  change meaning.
-- **I7. Brushes own their surfaces.**
-  - Each brush declares its surfaces: material, UV parameterisation and seams,
-    smoothing, and bevel or blend radius.
-  - Every emitted face carries the id of the brush and the surface it came
-    from. Output UVs are evaluated from that surface's parameterisation.
-  - No face gets default 0-1 UVs.
-  - Who owns a cut face is one explicit policy (Q `cut-face-surface`), not
-    array order.
-- **I8. Topology is regenerable.** The tree carries enough to regenerate good
-  topology wherever a consumer needs it, without hand retopology: edge flow on
-  curved primitives, strips at cuts, and LOD. The mesh is a cache. It is never
-  hand-edited and never read back.
-- **I9. Microbevels come from the tree.** The fine bevels at brush cuts are
-  derived from the same tree's signed-distance field, smooth-min style, with
-  radii that are brush or tree parameters. The field stays a distance bound,
-  never an overestimate, because sign tests and Newton projection depend on
-  that (`src/field.rs` header).
-- **I10. Stable identity.** Brushes and surfaces keep their identity across
-  print, parse and Blender edits (Q `brush-identity`). A receipt, a fit or a
-  heatmap that names a brush still names the same brush after a round-trip.
-- **I11. Brokkr's authority map holds.**
-  - Blender owns Blender truth: the source mesh, selection, viewport and undo.
-  - Brokkr owns the contract, admission and receipts.
-  - `brokkr-ctl` is a caller. It owns no state, no policy and no receipt
-    ledger (`docs/agent-access-cut.md` Cut 5, authority map).
-  - The exit code derives from the receipt, never from "the write succeeded".
-  - Agent commands are off until the operator enables them, as on the Unity
-    side (F5).
-  - Command ids are single-use (F6).
-  - Every mutating Blender command is one undo step.
-- **I12. Brokkr is better than the MCP bar, not equal to it.** Brokkr matches
-  the bar on viewport sight, code execution and API docs. It reads Edit Mode
-  selection live. On top of that it adds typed admitted intents with receipts,
-  undo-safe transactions, and a transport that does not admit arbitrary local
-  processes.
-- **I13. A CLI, not an MCP server.** The agent's hands are a stupid-simple CLI
-  whose `--help` is the schema, and whose outputs are paths and plain text.
-- **I14. Source is evidence.** The Tripo mesh is read-only reference. The loop
-  never edits it. The Tripo-mesh-as-bake-source rule of the Aetheria release
-  map stands.
-- **I15. One consumer path into Aetheria.** The lowered hull reaches Aetheria
-  through the existing ship pipeline, Blender add-on Package into the ship
-  `.cc` (`aetheria-release:ruling:schematic-is-designated-mesh`). This campaign
-  adds no second exporter.
-- **I16. Open and general.**
-  - Everything is open source (`eureka-body:ruling:always-open-source`).
-  - Geometry.Csg stays a general library with a clean public API. A capability
-    a reasonable consumer expects is not cut because Aetheria does not use it.
-  - The library does not acquire Aetheria vocabulary.
+### Owners, inputs, outputs, mock points
 
-## Settled direction (rulings in the mind, campaign brush-tree)
+| Owner | Inputs | Outputs | Mock point |
+|---|---|---|---|
+| Tree (Geometry.Csg) | text through the one commit primitive | typed tree revision | in-memory store |
+| Field | tree part | distance and gradient at a point | trait; analytic test shapes |
+| Cage generator | field, declared creases, target face budget | cage with crease flags | trait; the hand cage is a fixed implementation |
+| Refit | cage, field, subdivision rule | moved cage vertices | linear limit operator, injectable |
+| Kernel | tree part | mesh with per-face brush and surface ids | trait |
+| Scorer | two meshes | the bar's numbers | pure mesh math, no Blender |
+| Brokkr bridge | intents from `brokkr-ctl` | receipts, objects in the ship file | directory store or loopback, per `blender-transport` |
 
-- Mesh CSG is the main representation.
-- Octahedral impostors are a far-LOD tier only.
-- Brick-map marching of interval-pruned tapes stays CultMath research.
-- Unity's built-in pipeline is used by choice, with our own shaders. Its
-  deprecation is never counted as a cost.
+The cage generator is the owner nobody has built: runs 5-7 produced dense field-aligned meshes, never
+a cage. It sits behind a port so that candidates can be swapped and scored against the bar below.
 
-## Not in scope, and not consumers
+## The hand cage as the measuring stick
 
-- **Hull panel decals.** A separate later campaign
-  (`aetheria-release:ruling:panel-lines-mesh-decals`).
-- **The Aetheria/Hull shader.** It belongs to aetheria-release. This campaign
-  emits UVs and normals the shader can use. It does not edit the shader.
-- **Brick-map or tape SDF rendering, and runtime raymarching.** These stay
-  CultMath research (`docs/cultmath-tape-target.md`, parked).
-- **Impostor generation.** It is named as a derived far-LOD tier. Whether this
-  campaign builds it is Q `impostor-scope`, recommended out.
-- **Unity agent access.** Unity's `brokkr-command` and its intents are not
-  consumers and are not changed. `brokkr-ctl blender` must not fork the Unity
-  contract.
-- **CultCache Studio.** It may display the tree `.cc` like any CultCache
-  document. It gains no brush-tree editor in this campaign
-  (`aetheria-release:ruling:studio-is-the-authoring-pane` covers hull data,
-  not brush authoring).
-- **The prefab CDN pipeline and the Unity-Blender sync organ.** Not consumers.
-- **Training models.** The loop uses a frontier model with tools it builds and
-  uses (`aetheria-release:ruling:mesh-probe-exploit-not-measure`). Learned
-  encoders of the CAD-Recode or MeshCoder kind are prior art, not scope.
-- **Benchmarking the model's unaided spatial reasoning.** Explicitly not a goal
-  (same ruling).
-- **VibeGeometry's deleted scene-generation tree.** Read for its scars, not
-  revived.
+**What it is** (GameCult.Geometry.Csg `docs/research/dexter-quiet-cage/` @ d426f86, measured
+2026-10-12 from `cage_raw.obj` and `cage_eval.obj`):
 
-## Canonical implementations
+- Half hull: 29 vertices, 25 faces (19 quads, 6 triangles), the mirror seam open (12 boundary edges).
+  Mirrored, about 50 faces for the whole hull.
+- Creases: 9 edges at 1.0 forming one chain, vertex 5 (x = 0, nose) to vertex 22 (x = 0.003, tail),
+  so the mirror closes it into one loop round the wing rim.
+- Evaluated at subdivision level 3: 3,154 vertices, 3,152 faces, all quads, no boundary, 31 vertices
+  of valence other than 4 (about 10 per 1000 vertices).
+- No UVs.
+- Fidelity to the scan, vertex to nearest vertex, % of the hull diagonal (1.492):
+  cage to scan mean 0.88, p95 2.04, max 3.11; scan to cage mean 1.29, p95 4.12, max 6.03.
 
-- **The brush tree types, the text printer and parser, the kernel, the field,
-  per-primitive distance, and the fitter math (subject to Q `fitting-home`):**
-  `GameCult.Geometry.Csg`, Rust.
-- **Persistence:** through CultLib `packages/cultcache-rs`, not hand-rolled
-  `rmp_serde` tuples.
-- **Agent CLI and Blender adapter:** `Brokkr`. `brokkr-ctl` and the
-  `surfaces/blender/brokkr_bridge` add-on, over a Blender command contract
-  extending `brokkr.blender.command_intent.v0` and `.command_receipt.v0`.
-- **Consumer:** `Aetheria`'s `tools/blender/aetheria_ships` add-on, through its
-  existing Package.
+**Why the scan stays the shape reference.** The operator's words: "I'm afraid I had to take a bit of
+artistic liberty to get the cage to behave, mostly because of how creases work in Blender (generates
+horrible geometry if the crease path isn't closed)". The liberty was a concession to the tool, so the
+cage's departures are a tolerance band, not a new shape. Whether her cage should instead become the
+shape reference is question `fidelity-reference`.
 
-## Evidence (DocRefs)
+**The fidelity bar.** The evaluated output of a `field` part, measured the way the cage was (vertex to
+nearest vertex against the same scan, both directions, at a vertex count within half to double the
+cage's 3,154), is no worse than the hand cage in any of the six numbers above. Before the first cut
+uses the shared scorer (chamfer, F@2 %, silhouette IoU, run 4's `tools/common.py`), the hand cage's
+score under it is recorded as a body fact, and the bar is then also "no worse than the cage there".
 
-- `GameCult/GameCult.Geometry.Csg` `docs/research/brush-surfaces-and-sdf-bricks-prior-art.md` @ df89568
-- `GameCult/GameCult.Geometry.Csg` `docs/research/octahedral-impostors-prior-art.md` @ 5b5dc34
-- `GameCult/CultLib` `docs/research/inverse-procedural-modelling-prior-art.md` @ 6bdc23c9
-- `GameCult/Brokkr` `docs/research/blender-mcp-capability-bar.md` @ f97d4dc
-- `GameCult/GameCult.Geometry.Csg` `docs/realtime-csg-doctrine.md` @ 5b5dc34
-- `GameCult/Brokkr` `docs/agent-access-cut.md`, `docs/brokkr-adoption-cut.md`, `docs/provider-contract.md` @ f97d4dc
-- Pending: the mesh probe's `run1/RESULT.md`. Self commits it into Brokkr or the
-  crate's `docs/research/` and cites it once it exists.
+**Attribution.** Every measurement reports two parts separately: the program's zero set against the
+scan, and the cage's limit surface against the field. Run 7 misdiagnosed the wall for a whole spike
+because only the end-to-end number existed.
+
+**The cage-quality bar**, from the same cage:
+
+- Size: at most 4x the hand cage's face count for the hull (about 200 faces). The factor is a proposal.
+- Faces: quads and triangles only, no n-gons; triangle share at most the hand cage's (6 of 25, 24 %).
+- Creases: every crease chain is a closed loop, or ends on the mirror plane where its mirror closes it.
+- Limit mesh at level 3: one shell, watertight, at most 2x the hand cage's 31 irregular vertices.
+- UVs (the cage has none, so this comes from the bar's words and run 3's v7): islands follow parts,
+  seams on crease loops and part boundaries, mean |log2| area distortion at most 0.1 (v7: 0.076).
+
+## Not yet known (research owed before cuts are mapped)
+
+- **How the cage is generated.** Candidates in the research: a quad layout from the cross field
+  (patent US 12086939; Kloiber and Augsdorfer 2020), a coarse remesh then refit (run 6 at 144-342 faces:
+  115-170 poles per 1000 vertices), a template cage refit (run 7 "Next" item 4). No measured source
+  covers coarse feature-aligned patch layouts.
+- **What text authors a `field` part.** OpenSCAD has no smooth union, so `openscad-target` and
+  `text-is-a-surface` from r1 cannot both hold for smooth-min parts.
+- **How a `field` part and a `kernel` part meet** on one hull. The research found no convention
+  (subd-cages file s.0, s.5).
+
+## Research it rests on
+
+All in GameCult.Geometry.Csg `docs/research/` on `eureka/brush-tree`:
+
+- `dexter-quiet-cage/` @ d426f86: the reference cage.
+- `shippable-bar/` @ 253f34d: the operator's bar and render.
+- `mesh-probe-run1/` to `mesh-probe-run7-im-field/`: OpenSCAD and CSG fits (1), CSG lowerings (2),
+  a designed cage (3), SDF with smin and a field cage (4), QuadriFlow (5), Instant Meshes (6), the
+  Instant Meshes fork with the SDF's cross field and a hard rim (7).
+- `subd-cages-mixed-hulls-and-open-kernels.md` @ 390db63: cage fitting, remeshers as cage seeds,
+  creases versus bevels, mixed assets, open kernels.
+- `primitive-seams-and-sdf-bevel-meshing-prior-art.md`, `brush-surfaces-and-sdf-bricks-prior-art.md`,
+  `openscad-evaluators-and-csg-export.md`, `octahedral-impostors-prior-art.md`: the kernel path.