Сортировочная ячейка Isaac Sim: CV-пайплайн и меши товаров

Замкнутый контур "поток -> CV -> механика": товары идут по конвейеру с шагом 700 мм,
класс определяется стереопайплайном во время движения, пушер и плуг реагируют физически.

Состав:
* control_test/ - ячейка и CV. run_sorting_cv.py + cv_worker.py (два процесса, потому что
  torch внутри Isaac роняет сцену), cell.py (физика лент, плуга, пушера), measure_plane.py
  (замер габаритов), README.md и .memory.md с замерами, проблемами и ловушками
* robozon_sorter/ - модули симуляции, scripts/ - утилиты, scene/ - сцены
* assets/ - меши товаров, плуг, объекты Objaverse

Бейзлайн CV: DEFOM-Stereo vitl, вход 480, iters 24, кроп зоны осмотра, без сегментации.
На потоке 700 мм - классы 8/9, габариты MAE 32.8 мм, 469 мс на товар при такте 700 мс.

Веса моделей (4.5 ГБ) и пропсы конвейера NVIDIA (274 МБ) не включены - источники и
команды скачивания в MODELS.md. Выход прогонов (captures/, runtime/) не включён:
воспроизводится.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/build_plow_cell.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+"""Build scene/plow_cell.usd from the authored 90_degree.usd.
+
+    python scripts/build_plow_cell.py [path/to/90_degree.usd]
+
+The source is the original authored cell - conveyor art, the Y-split pusher, the plow
+(``DiverterEnd``) and its OmniGraph drive script exactly as built. This script does not
+regenerate geometry; it only makes the file self-contained inside this repo:
+
+1. **References re-pointed.** The source pulls conveyor art straight off the Omniverse S3
+   bucket and the plow meshes from its own folder. Both are re-pointed at the repo's
+   ``assets/`` tree so the scene composes offline (``scripts/fetch_assets.py`` fills
+   ``assets/conveyors/``).
+
+2. **Baked drive animation stripped.** The pusher's ``PusherSlide`` carries a long
+   ``targetPosition.timeSamples`` track. Time samples outrank the attribute default, so
+   anything that tries to *control* that drive - the authored script node or Python - is
+   overwritten every frame while the timeline runs. The track is dropped; the drive keeps
+   its authored gains and limits. (The plow's own ``ArmHinge`` is already clean in
+   90_degree.usd; the earlier fixed.usd bakes it too, hence the pattern matches both.)
+
+The authored ``DiverterAnimGraph`` script node is deliberately kept: open the scene, press
+Play, and the cell demonstrates itself the way it was built. ``sim/plow_cell.py`` switches
+that graph off when you want to drive the plow from code instead.
+"""
+from __future__ import annotations
+
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+OUT = ROOT / "scene" / "plow_cell.usd"
+DEFAULT_SRC = (Path.home() / "Desktop" / "isaac_sim_project" / "test_isassc" / "90_degree.usd")
+
+S3 = ("https://omniverse-content-production.s3-us-west-2.amazonaws.com/"
+      "Assets/Isaac/6.0/Isaac/Props/Conveyors/")
+
+# asset path in the source  ->  path relative to scene/
+REFS = {
+    f"{S3}ConveyorBelt_A06.usd": "../assets/conveyors/ConveyorBelt_A06.usd",
+    f"{S3}ConveyorBelt_A24.usd": "../assets/conveyors/ConveyorBelt_A24.usd",
+    "./plow_base.usd": "../assets/plow/plow_base.usd",
+    "./plow_arm.usd": "../assets/plow/plow_arm.usd",
+}
+
+# Baked drive tracks fight every attempt to control a diverter. In 90_degree.usd only the
+# pusher's linear drive carries one (the plow's angular drive is already clean), but the
+# earlier fixed.usd bakes the plow too - match both so either source builds the same way.
+BAKED = re.compile(r"drive:(linear|angular):physics:targetPosition\.timeSamples")
+
+
+def usdcat(src: Path, dst: Path) -> None:
+    if not shutil.which("usdcat"):
+        sys.exit("usdcat not found - it ships with USD / Isaac Sim and is needed to "
+                 "convert the binary .usd to text and back")
+    subprocess.run(["usdcat", str(src), "-o", str(dst)], check=True)
+
+
+def strip_baked_track(text: str) -> tuple[str, int]:
+    """drop `<drive target>.timeSamples = { ... }` blocks"""
+    out, skipping, dropped = [], False, 0
+    for line in text.splitlines(keepends=True):
+        if not skipping and BAKED.search(line) and line.rstrip().endswith("{"):
+            skipping, dropped = True, dropped + 1
+            continue
+        if skipping:
+            if line.strip() == "}":
+                skipping = False
+            continue
+        out.append(line)
+    return "".join(out), dropped
+
+
+def repoint_refs(text: str) -> tuple[str, dict[str, int]]:
+    counts = {}
+    for old, new in REFS.items():
+        n = text.count(f"@{old}@")
+        if n:
+            text = text.replace(f"@{old}@", f"@{new}@")
+        counts[old] = n
+    return text, counts
+
+
+def build(src: Path) -> Path:
+    if not src.exists():
+        sys.exit(f"source scene not found: {src}")
+    OUT.parent.mkdir(parents=True, exist_ok=True)
+
+    with tempfile.TemporaryDirectory() as tmp:
+        flat = Path(tmp) / "src.usda"
+        usdcat(src, flat)
+        text = flat.read_text()
+
+        text, refs = repoint_refs(text)
+        text, dropped = strip_baked_track(text)
+
+        missing = [k for k, v in refs.items() if v == 0]
+        if missing:
+            print("warning: reference not found in source (layout may have changed):")
+            for m in missing:
+                print(f"  {m}")
+
+        edited = Path(tmp) / "edited.usda"
+        edited.write_text(text)
+        usdcat(edited, OUT)
+
+    print(f"built {OUT.relative_to(ROOT)} from {src}")
+    for old, new in REFS.items():
+        print(f"  ref  {refs[old]}x  {Path(old).name:24s} -> {new}")
+    print(f"  drop {dropped}x baked drive targetPosition.timeSamples")
+    left = re.findall(r"@(https?://[^@]+)@", OUT.read_text(errors="ignore")) if OUT.suffix == ".usda" else []
+    if left:
+        print(f"  warning: {len(left)} remote reference(s) still present")
+    return OUT
+
+
+if __name__ == "__main__":
+    build(Path(sys.argv[1]) if len(sys.argv) > 1 else DEFAULT_SRC)