[wverri]

Stacked on #37 (vendor update to UO_Model3D b212cee): this branch includes that commit. Review only the last commit, b344d81. cloth_sim needs the pin fix from #37; the other options also work on e9544f6.

Change

New optional tools/uo-content build settings, which we used to build custom UO equipment:

• Weapon parts weapon1h, axe2h, polearm. They bind the item to the canonical body's weapon bones weapon1h.R, axe2h.L and polearm.L (backend uo_bind_item.py), so the item follows the class motion calibrated on the original weapons. The existing weapon part stays rigid in hand.R. The new parts get BODY_GAP 0, a starter blade and an auto-fit size (without these, starter() and the auto fit raised KeyError for any part outside the old four), plus equipment templates and layers, the studio picker and the Fit Lab poke rule.
• weapon_motion {bone: entry} replaces one weapon bone's calibration for a single build and re-keys the weapon bones before the bind. Example: a bow.L class fitted on bows alone. The stock class is fitted on bows and crossbows together and turns a bow flat at the release of attack_bow.
• bow_draw bends a bow during the draw. The item brings shape keys draw and string_x/y/z. The build keys the draw weight and the nock-to-hand offset per action frame on the rig, and drivers move the keys, so the limbs bend and the string follows the fingers. The optional orient turns the bow toward the drawing hand. import_asset keeps the asset's shape keys when bow_draw is on.
• cloth_sim (robe, skirt) runs the backend uo_cloth_sim.py on the saved item.blend in a separate Blender (cloth_sim_run.py, because uo_cloth_sim expects bpy as a module), and the renderer adds cloth_sim.npz to the leg push. Meshes whose modifiers change the vertex count are refused up front with the reason. The procedural template's Solidify used to fail deep inside Blender with Array length mismatch.

pipeline.py validates every new field. All of this is documented in tools/uo-content/README.md.

Verification

• New tests/unit/test_uo_content_spec.py (24 cases: parts, accepted and rejected cloth_sim / weapon_motion / bow_draw / orient). Full pytest tests: 245 passed, 2 skipped. The 2 failures are the Windows-path tests that also fail on main under macOS.

• node --test tools/fit-lab/web/*.test.mjs: 11/11.

• tools/uo-content/test_content.py: 8/9. test_partial_import_refused fails the same way on main.

• Real Blender 4.5 LTS preview builds on macOS:

  • weapon1h from a prompt (no asset) builds and binds rigid on weapon1h.R. Before, this raised KeyError.
  • A synthetic bow with bow_draw weights [0,.4,.8,1,1,.3,0] on action 18: the shape keys follow the weights per frame (draw 0 → 0.4 → 0.8 → 1 → 1 → 0.3 → 0), with the string offset tracking the hand, and the bow turns in the 3 orient frames.
  • A robe GLB with cloth_sim {"arm_goal": -1, "thick": 0.005, "in_max": -1}: 2 actions simulated in 40 s and the sheet renders. The template robe with cloth_sim is refused with a clear ValueError.

• These options shipped in our production items (two bows, a crossbow, a robe, 1H/2H weapons) before this PR. The bow shape keys were renamed to English here.

• Tests pass; behavior changes have meaningful coverage.

• No UO data, commercial assets, private mappings, credentials or local paths included.

• Any media has redistribution permission and recorded provenance.

• Blender/render changes were checked with actual renders, or remaining verification is stated.

Risks and remaining work

• cloth_sim adds about a minute to a preview and runs --jobs 1 only, because inside Blender sys.executable is not Blender.
• weapon_motion entries are checked for shape (parent, pivot, dir, poses), not for sensible values.
• The full 35-action build was not re-run on this exact commit for every new part.