fix(screwcap): regenerate bottle_cap + juice_shot USD — mount offset applied once, MJCF contact excludes carried over
Regenerates both screw-cap USDs. The published blobs put the cap in the wrong place on IsaacSim while MuJoCo, which never reads them, stayed correct — hand_track.open_bottle_cap RT2 frames showed a cap floating above its bottle.
Two independent defects, fixed in RoboVerse/scripts/mjcf_screwcap_to_usd.py (WUJI_SimBench PR #124):
- The mount offset was applied twice.
caphangs off an intermediatecap_screwlink (PhysX articulations must be trees); that link's origin already IS the mount offset, so carrying the MJCF's<body name="cap" pos="0 0 Z">into the second joint's frame as well floated the cap Z metres high. - The MJCF's
<contact><exclude body1="bottle" body2="cap"/>had no USD counterpart. PhysX read the authored cap-over-neck overlap as a collision and drove the cap up its own slide joint until the convex hulls cleared —cap_slideparked at 32 mm and stopped tracking the commanded value. Now emitted asUsdPhysics.FilteredPairsAPI.
Measured — cap height above the bottle body at commanded slide 0 / 18 / 36 mm (IsaacSim, states set and drawn, no physics steps: the split-render path these render-grade USDs exist for):
| bottle_cap | 0 mm | 18 mm | 36 mm |
|---|---|---|---|
| MuJoCo (source of record) | 0.140 | 0.158 | 0.176 |
| published USD | 0.280 | 0.280 | 0.288 |
| this PR | 0.140 | 0.158 | 0.176 |
juice_shot, at 0 / 10 / 20 mm: MuJoCo 0.069 / 0.079 / 0.089, published 0.138 / 0.148 / 0.158 (exactly +69 mm, its own mount offset), this PR 0.069 / 0.079 / 0.089.
The MJCFs are unchanged, so MuJoCo behaviour and the asset physics regressions are untouched (15 passed).
Land together with WUJI_SimBench PR #124 — either alone leaves the published asset and the converter disagreeing.