Wooden Bucket

A showcase piece, not an example. Procedural coopered pail (16 staves with seeded width jitter, a bottom of three boards seated in a croze above a chime, iron hoops lofted on the stave faces, ear plates and rings, a three-strand rope bail through the rings) then the shipped pipeline: unique-cell UVs, Cycles high-to-low normal bake, LOD chain, convex collider, Unity glTF export.

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. The floor follows the inner stave polygon. Ear plates sit on the outer stave face below the rim; the bail is a semicircle whose ends pass through the rings and run on below them. --float-handle shrinks that semicircle and lifts it by what it lost, so the envelope stays put and only the bail-ear gap fails; --float-bottom shrinks the floor out of the croze.

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 rose from 4272 to 4872 in the quality pass: overlapping identical staves, circular hoops, and a 12-box bail became 16 jittered staves, chord-seated hoops, a polygonal croze floor, and a round bail through the ear rings. The second pass took it to 5458: the bail became three-strand rope (48 segments of a nine-vertex lobed section, running on through the rings) and the floor three boards.

DECIMATE COLLAPSE triangle counts are not identical across series, so LOD2 ratios differ slightly between versions. 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. 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#

Falsifiers#

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

Rope and ears#

The bail was a smooth eight-sided tube in a rope material, and it read as a plastic hose. It is now laid rope: a three-lobed section turned one vertex step per ring, so the lobes wind along the bail as strands. The section's frame is fixed to the bail's plane, so the lay does not jump where the ends turn vertical.

The ring offset from the ear plate was RING_MAJOR * 0.25, which put the rope's axis 3.25 mm off the plate and its body through it (hidden by the ring in the old stills). The offset is now sized from the rope's lobes plus 0.5 mm, and Rope clears the ear plates asserts it. --sunk-rope restores the old offset and puts 19 rope vertices inside a plate. The outer AABB was re-fitted to the honest envelope: 12.5 mm wider across the ears and 6 mm taller.

Surface#

Every stave and board carries a seeded PlankTone and a GrainDir (its own long axis) as face attributes, and wood_material stretches grain along that axis. The hoops, plates and rings are dark rusted iron. The temp .glb is removed once its size is measured.

Run#

blender --background --python wooden_bucket.py --
blender --background --python wooden_bucket.py -- --skip-decimate
blender --background --python wooden_bucket.py -- --stray-vert
blender --background --python wooden_bucket.py -- --lift-z
blender --background --python wooden_bucket.py -- --short-staves
blender --background --python wooden_bucket.py -- --float-handle
blender --background --python wooden_bucket.py -- --float-bottom
blender --background --python wooden_bucket.py -- --round-band
blender --background --python wooden_bucket.py -- --one-piece-bottom
blender --background --python wooden_bucket.py -- --sunk-rope
blender --background --python wooden_bucket.py -- --output bucket.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.