Wooden Barrel

A showcase piece, not an example. Procedural wine-cask (20 staves with seeded width jitter, heads of four boards seated in a croze below a chime, iron hoops lofted on the stave faces, a bung) 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, which is what made the old capped cylinder float off every face. Heads follow the inner stave polygon, not a circle, so they fill the croze instead of leaving triangular slots at every joint. Each head is that outline cut across into four boards with a 1.5 mm seam, so the seat is unchanged and the head no longer reads as a lid.

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 4312 to 7216 in the quality pass: 12 identical staves with 5 mm daylight and circular hoops became 20 jittered staves, 8-ring bulge, chord-seated hoops, polygonal croze heads, and a bung. Cutting each head into four boards added 96 more (7312).

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. Export byte counts differ by 16 B 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 seven were run on 4.5.11, 5.1.2 and 5.2.1 and returned the same code on each.

Surface#

The staves were one flat tone and the hoops bright polished steel. Each stave and each head board now carries a seeded PlankTone and a GrainDir (its own long axis) as face attributes. wood_material stretches grain along that axis, so it runs up the curved staves and across the head boards. The hoops are dark rusted iron, the same recipe as shipping-crate. The temp .glb is removed once its size is measured.

Run#

blender --background --python wooden_barrel.py --
blender --background --python wooden_barrel.py -- --skip-decimate
blender --background --python wooden_barrel.py -- --stray-vert
blender --background --python wooden_barrel.py -- --lift-z
blender --background --python wooden_barrel.py -- --short-staves
blender --background --python wooden_barrel.py -- --float-head
blender --background --python wooden_barrel.py -- --round-band
blender --background --python wooden_barrel.py -- --one-piece-head
blender --background --python wooden_barrel.py -- --output barrel.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.