Anvil

A showcase piece, not an example. Procedural London-pattern anvil on a coopered timber stump (16 jittered staves, chord-lofted iron hoops, a sawn head, spreading foot, pinched waist, one slotted face with hardy and pritchel through-holes, oval-lofted horn) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.

The face is one add_slotted_slab so hardy/pritchel are real holes in a single shell, not nubs glued onto stacked boxes. Hoops evaluate the same host_outer_r chord as the stave flats. --round-band is the falsifier: a circle of radius_at(z) instead of the chord.

It asserts budget conformance of the generated result. It does not witness an API contract. "It rendered without error" is not a check.

Composes skills mesh-editing-and-bmesh, bake-high-to-low, depsgraph-and-evaluated-data, engine-export-presets, and snippets bake_normal_high_to_low.py, setup_bake_target_image.py, lod_chain.py / decimate_to_budget.py, convex_hull_collider.py, export_preset_unity.py (helpers copied, not imported as a package).

Budgets#

Declared as named constants; every gate recomputes from the mesh, materials, UVs, evaluated LOD, collider, or export file.

Base triangles dropped from 6616 to 2988 in the quality pass: overlapping face boxes and a beveled superellipse horn became one slotted slab plus a circular oval loft. Hidden coincident faces were the waste.

DECIMATE COLLAPSE triangle counts are not identical across series — the gate is a ratio band, not an exact count. Bake pixels are stochastic; the gate is has_data plus operator FINISHED, not byte-identity. Stave-width jitter uses fixed seed 17, and the per-piece wood tone its own seed. Export byte counts differ on 5.2.1 (glTF serializer), not a gated axis.

Hygiene#

Recomputed from the generated mesh, not asserted about the script.

Joint fit and seat#

Waist, steel and stump#

The waist was lofted from ellipses, so under the rectangular face it read as a turned funnel, not a forged anvil. It is now a superellipse section (exponent 4.5) through eight stations: a broad foot, in to a pinch, and out into the underside of the face. Waist form measures corner reach at the narrowest ring: how far a section vertex fills its bounding rectangle's corner. --round-waist restores the ellipse and exits 19 (0.7071).

The steel was satin (metallic 0.92, roughness 0.32) and read as chrome; it is now dark forged steel with rust. Staves and head carry their own wood tone and grain. The stage grid grew from 14 to 60 m. The temp .glb is removed after its size is measured.

The hero dresses the scene without touching the checked mesh: up-facing steel (the working face and the top of the horn) is mixed toward bright, low-roughness metal by the geometry normal, as a hammer polishes it; a render-only cross-peen hammer lies on the floor beside the stump; and a low warm point light off frame stands in for the forge. The hammer is in the framing gate's element set, so it has to clear the frame edges too.

A later pass rebuilt the forging to London-pattern proportions. The reference is a 165 lb Peddinghaus: 25 in long, 10.5 in tall, a 5 in face and a 9.25 × 11 in base, so height is about 0.42 of length. The first build stood 0.18 m on 0.62 m: a 50 mm face board on a narrow stem over a small plate, with a needle horn.

• The stated body height is now 0.260 m (BODY_H, was 0.180). The face block is 75 mm thick, and the outer AABB z was refitted from 0.489 to 0.569.
• The body is one superellipse loft of eight rings. It starts at a broad foot (0.250 × 0.164 m, as large as fits inside the stump's chime), pinches below mid-height, and swells along the face's length into its underside. The heel's underside rises 30 mm toward its end.
• The horn is round-sectioned and about as wide as the table at its root. Its top runs on from the table, and its belly is deep enough to sweep into the throat. It has six rings, fewer than the body's eight, so the waist-form audit still finds the waist.
• The face block and table chamfer their corners. Hole mouths stay sharp.
• The polished face is a satin sheen (roughness 0.30). At 0.16 it was a mirror of the black stage.
• The staves are weathered oak. The hammer is lofted: a chamfered face, a swelled eye and a peen blade, on an oval handle.
• The hero turns the stand to 30 degrees for the profile, looks down onto the face, and aims at the bbox middle.

Falsifiers#

Each violates one named budget. All seven were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.

Run#

blender --background --python anvil.py --
blender --background --python anvil.py -- --skip-decimate
blender --background --python anvil.py -- --stray-vert
blender --background --python anvil.py -- --lift-z
blender --background --python anvil.py -- --short-staves
blender --background --python anvil.py -- --float-anvil
blender --background --python anvil.py -- --round-band
blender --background --python anvil.py -- --round-waist
blender --background --python anvil.py -- --output anvil.png

Smoke passes no flags.

Exit codes#

File-local. 9 is a valid check code. 10 is reserved for gallery_framing.check_framing on the --output path. 15–19 are the hygiene and joint-fit family.