passages: contiguous BVH node ranges + child-bound reuse (L83); scaling and serial floor measured

Exact through LOD2 (all near tile hashes equal L82). W8 LOD0-2: SW 1.09->1.06, FI 2.47->2.34,
TN 2.39->2.43 (noise), VS 1.20->1.18 s. Fast tier PASS.
Scaling W4/W8/W12/W16 (LOD0-2, FI): 3.59 / 2.48 / 2.33 / 2.34 s - flattens past W8-W12.
Estimated infinite-worker floor ~1.0 s FI/TN = shape compile (0.35-0.41 s, not overlapped:
no shape-free tiles in these views) + slowest single LOD0 tile service (0.51-0.59 s).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Research/WorldAssemblerM3/Linux83/RunL83Hashes.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""Compare all LOD0-2 near tile hashes per stratum against L82."""
+from __future__ import annotations
+
+import json
+import re
+import subprocess
+import time
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[4]
+OUT = ROOT / "Saved/Linux/l83/hash-check"
+DATA = ROOT / "Standalone/data/owner_world.json"
+BINARIES = {
+    "L82": ROOT / "Saved/Linux/l82/bin/VoxelForgeCoreHeadless-clang19",
+    "L83": ROOT / "Saved/Linux/l83/bin/VoxelForgeCoreHeadless-l83-clang19",
+}
+CAMERAS = {
+    0: (8.0, 16.0, -372.2626953125),
+    1: (25.8369140625, 3.19921875, -737.0),
+    2: (19.166015625, -14.2001953125, -753.3740234375),
+    3: (-20.0625, -5.068359375, -900.353515625),
+}
+EXPECTED_NEAR = {0: 1408, 1: 1216, 2: 1344, 3: 1344}
+TILE_HASH = re.compile(
+    r"^\[PipelineTileHash\] lod=(-?\d+) x=(-?\d+) y=(-?\d+) z=(-?\d+) "
+    r"density=(0x[0-9a-f]+) mesh=(0x[0-9a-f]+) payload=(0x[0-9a-f]+) "
+    r"topology=(0x[0-9a-f]+)$", re.M)
+WHOLE_HASH = re.compile(
+    r"^\[PipelineWholeViewHash\] tiles=(\d+) density=(0x[0-9a-f]+) "
+    r"mesh=(0x[0-9a-f]+) payload=(0x[0-9a-f]+) topology=(0x[0-9a-f]+)$", re.M)
+
+
+def run(strate: int, version: str) -> dict:
+    OUT.mkdir(parents=True, exist_ok=True)
+    log = OUT / f"{version.lower()}-s{strate}.log"
+    camera = ",".join(f"{v:.12f}" for v in CAMERAS[strate]) + ",0,0"
+    command = [
+        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--",
+        "env", "VOXELFORGE_L81_PASSAGE_BOUND_PADDING_VOXELS=0", "timeout", "1740s",
+        str(BINARIES[version]), str(DATA), "--world-assembler-prototype",
+        "--stream-benchmark", "--stream-pipeline", "--workers=8", "--clip-radius=3",
+        "--max-clip-level=8", "--max-level=2", f"--camera={camera}",
+        "--stream-hash-tiles",
+    ]
+    start = time.monotonic()
+    with log.open("w", encoding="utf-8") as stream:
+        result = subprocess.run(command, cwd=ROOT, stdout=stream,
+                                stderr=subprocess.STDOUT, check=False, timeout=1740)
+    output = log.read_text(encoding="utf-8", errors="replace")
+    hashes = {
+        (int(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4))): m.group(5, 6, 7, 8)
+        for m in TILE_HASH.finditer(output)
+    }
+    whole = WHOLE_HASH.search(output)
+    if result.returncode or whole is None or len(hashes) != EXPECTED_NEAR[strate]:
+        raise RuntimeError(f"hash run failed or incomplete: exit={result.returncode} {log}")
+    return {
+        "version": version, "strate": strate, "exit_code": result.returncode,
+        "wall_s": round(time.monotonic() - start, 3), "tile_hash_count": len(hashes),
+        "whole_hash": whole.group(1, 2, 3, 4, 5), "hashes": hashes,
+        "log": str(log.relative_to(ROOT)),
+    }
+
+
+def main() -> int:
+    for path in (*BINARIES.values(), DATA):
+        if not path.is_file():
+            raise SystemExit(f"missing input: {path}")
+    comparisons, runs = [], []
+    for strate in range(4):
+        pair = {version: run(strate, version) for version in ("L82", "L83")}
+        a, b = pair["L82"], pair["L83"]
+        mismatch_keys = sorted(key for key in set(a["hashes"]) | set(b["hashes"])
+                               if a["hashes"].get(key) != b["hashes"].get(key))
+        comparison = {
+            "strate": strate, "tiles": len(a["hashes"]),
+            "tile_hashes_identical": not mismatch_keys,
+            "whole_hash_identical": a["whole_hash"] == b["whole_hash"],
+            "mismatch_count": len(mismatch_keys), "first_mismatches": mismatch_keys[:8],
+            "l82_whole_hash": a["whole_hash"], "l83_whole_hash": b["whole_hash"],
+        }
+        comparisons.append(comparison)
+        runs.extend({k: v for k, v in row.items() if k != "hashes"} for row in pair.values())
+        print("[L83HashComparison] " + json.dumps(comparison, sort_keys=True), flush=True)
+    (OUT / "summary.json").write_text(
+        json.dumps({"comparisons": comparisons, "runs": runs}, indent=2) + "\n",
+        encoding="utf-8")
+    return 0 if all(row["tile_hashes_identical"] and row["whole_hash_identical"]
+                    for row in comparisons) else 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())