wip(unreal): round 3 -- owner's in-game defects classified; opening room fixed; Core biome query

Luna, integration round 3, from the owner's four in-game screenshots:
- Capsule rings at the opening and the shaft continuing through the cave room were Core
  world defects: the synthetic bore is removed and the opening gets a finite origin room
  and floor (solid below). New world version, W1/W8/W16 identical: density
  a8bcb72d41092503, mesh 90f29ba15e24579f, payload 82c6b489e7bb7fd7, topology
  7b99448a1f844f2c.
- B-side landing and surface: headless coverage found no missing tiles or LOD-transition
  gaps (960 / 640 fine tiles compiled after travel); best explained by Core's missing
  SurfaceWorld representation. Null-RHI cannot rule out a presentation-only issue.
- Core mode GetBiomeAtWorldLocation now answers (e.g. Biome_Surface_Plain); biome
  terrain itself is not generated yet (proposal: native Core SurfaceWorld evaluator).
Owner checked the Step29 viewer himself: the surface strate type is absent there too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/UNREAL_INTEGRATION_REPORT.md

@@ -1,8 +1,11 @@
-# Unreal Core integration report — round 2
+# Unreal Core integration report — rounds 2–3
 
 Date: 2026-10-08  
 Branch: `unreal/core-integration`
 
+The initial sections preserve the round-2 integration baseline. The round-3 addendum records the
+owner's visual findings and current status, superseding earlier statements where indicated.
+
 ## Result
 
 Goals 1 and 2 now pass in BuildHost: an `AVoxelWorld` with Core mode enabled matches standalone Core
@@ -145,10 +148,12 @@ final export itself retains the asset values.
   content, and this asset is not part of the plugin; the staged copied content also lacks that
   package. It did not prevent schema resolution, hash checks, or walkability. The owner should
   verify whether that reference is stale or whether the asset needs restoring in project Content.
-- Core mode's legacy biome query returns empty because Core exposes no biome query API. `CollisionOnly`
-  anchor movement is asserted; `FullVisual` uses the same reconciliation path but was not independently
-  checked. BuildHost runs with null rendering, so the test proves generated payload and collision
-  state, not a human visual review of the result.
+- At the end of round 2, Core mode's legacy biome query returned empty because Core exposed no biome
+  query API. Round 3 adds a Core-mode query through the copied owner biome evaluator; it does not add
+  biome terrain or decorations to the Core field. `CollisionOnly` anchor movement is asserted;
+  `FullVisual` uses the same reconciliation path but was not independently checked. BuildHost runs
+  with null rendering, so the test proves generated payload and collision state, not a human visual
+  review of the result.
 - Only the five explicitly named world assets were copied and SHA-checked. No owner editor was
   opened, and no owner project build or asset write was performed.
 
@@ -192,3 +197,99 @@ The owner can now try the switch described above. BuildHost proves Core tile par
 collision-body bookkeeping, anchor entering/leaving, and transaction-based carving. The remaining
 validation is the owner's editor compile and an in-game visual/walkability/carve check; the narrow
 switch-off automation is not an actor-level legacy-route assertion.
+
+## Round 3 — owner visual report, classification, and fixes (2026-10-08)
+
+The owner had already built the plugin in his own game and confirmed that the Core toggle worked and
+performance looked fine. I compared the four small images in `Standalone/owner_shots/unreal_core_r2/`
+with owner-field and shape-world viewer modes at the B and surface locations, checked the owner's
+`BuildOriginLandingGeometry`/passage definitions, and extended the BuildHost actor proof to inspect
+desired keys, hashes, meshes, and LOD faces. Viewer comparisons were captured before the geometry
+correction; the final test recompiled the corrected field in BuildHost.
+
+| Reported defect | Standalone and layout evidence | Unreal Core headless evidence | Classification and outcome |
+|---|---|---|---|
+| 1. Capsule rings at the city/surface opening | Owner passage is a short entry into a finite origin room. Core shape-world instead added a segmented 256-voxel bore; owner-field mode has no such continuation. | Room center `+4.125` (air); floor below center and side `-4.125` (solid); above floor center and side `+4.125` (air). | **(ii) Core world defect, also visible in shape-world. Fixed.** Removed the synthetic bore and added the finite room/floor. |
+| 2. Bore continues through a normal cave room | Owner layout ends the entry at the room; no shaft continues through it or into the lower seal. The same Core bore passed through it. | 32 voxels below the room floor samples `-4.125` (solid). | **(ii) Core world defect, also visible in shape-world. Fixed.** |
+| 3. B-side landing has jagged/sawtooth edges | At B, owner-field and shape-world fields differ: Core shows a smooth cavern/floor while owner reference has the authored landing/terrain form. The landing is in the lower biome/SurfaceWorld portion of the layout. | All expected 2,553 visual keys load and match standalone hashes. B travel compiled 960 fine tiles; 3,438 neighbour faces checked, including 432 LOD-transition faces; no expected visual key is missing. | **(iii) Missing Core SurfaceWorld/biome representation is best supported.** The suspected missing-neighbour/LOD coverage fault is absent at the tested pose. Null-render headless testing cannot rule out a final RMC presentation artifact; owner should recheck after rebuild. |
+| 4a. Surface strate is not surfacy | Shape-world viewer lacks the owner's biome-composed SurfaceWorld; owner-field mode shows rolling biome terrain. The owner separately confirmed the surface strate type is absent in his viewer. | Core query reports `Biome_Surface_Plain`, index 2, but geometry remains the Core shape field. | **(iii) Missing Core feature: biome terrain. Not implemented this round.** Cheap biome query is implemented. |
+| 4b. Coarse shapes may not page detail | Hypothesis: travel failed to trigger fine compilation. Standalone Core uses the same clipmap policy. | Surface travel compiled 640 fine tiles. Visual set and tile hashes match standalone; 3,588 neighbour faces checked, including 448 LOD-transition faces, with no missing expected visual key. | **(i) Unreal paging bug not reproduced.** `StartPendingCoreRegionCompile` paged detail at the tested location. Extra loaded keys included collision-only/stale support; validator filters these and proves the exact visual set. |
+
+### Changes and hashes
+
+- `Standalone/Core/src/ShapeWorldInternal.h`: add the owner-layout finite origin room/floor per
+  strate, remove the synthetic long surface-entry bore, and ignore invalid/default passage landing
+  descriptors that made tiny false landings.
+- `Source/VoxelForge/Private/VoxelWorld.cpp`: Core-mode `GetBiomeAtWorldLocation` now calls the
+  copied owner biome evaluator using its authored 12.5 cm query scale. Core terrain still uses 25 cm
+  voxels; the exception is local to this legacy biome query.
+- `Source/VoxelForgeEditor/Private/VoxelForgeExploreCommandlet.cpp` and
+  `Tools/TestVoxelForgeCoreWorldHost.ps1`: probe the room/floor, W1/W8/W16 determinism, travel to B
+  and surface, exact visual keys/hashes, LOD face coverage, fine compilation, and biome result.
+
+The corrected world intentionally changes the four aggregate hashes. W1/W8/W16 initial clipmap
+results are identical:
+
+| Hash | New value | R2 value |
+|---|---:|---:|
+| Density | `0xa8bcb72d41092503` | `0xdb2991c73215af4c` |
+| Mesh | `0x90f29ba15e24579f` | `0x8236c5edd7fc8e4f` |
+| Payload | `0x82c6b489e7bb7fd7` | `0x4c48fa75a543d58e` |
+| Topology | `0x7b99448a1f844f2c` | `0xbea22e76b34a4dfc` |
+
+B travel hashes: density `0x02ffd603879b7fdc`, mesh `0xde3bfc6069854070`, payload
+`0x14f98868de7986c5`, topology `0xdf960f8a26aafdc0`. Surface travel hashes: density
+`0x7f878c0933972c7f`, mesh `0x18d63306f5215f10`, payload `0x18b6e682e2a17505`, topology
+`0xe89da4150dc053c9`. At surface `desired=2553`, while actor `loaded=3334` includes support/stale
+keys during the move. The validator filters collision-only support, then proves every expected visual
+key and hash; it does not claim support-set quiescence.
+
+### Biome design proposal
+
+Recommended direction: add a deterministic `SurfaceWorld` evaluator to the Core shape-world model,
+fed by resolved biome definitions, surface-generation parameters, and fixed-order noise. Keep biome
+identity/blend selection in the immutable worker snapshot and add per-column height/biome caching so
+mesh samples reuse height work. This makes the surface, biome query, and decoration inputs one pure
+field. The port is medium-to-large work. Uncached per-sample biome/noise could slow detail tiles;
+column caching bounds the added cost. Determinism is straightforward to preserve with fixed coordinate
+hashing/math and worker-count hash tests.
+
+Routing only SurfaceWorld strates through the copied legacy `UVoxelGenerator` in Core is a smaller
+compatibility bridge with higher immediate visual fidelity. It likely costs about the legacy field
+evaluation per sample, duplicates a second field implementation, and inherits legacy float/platform
+behavior. It should be checked across worker counts and platforms. A better staged design is an
+explicit strate-evaluator interface: use the port long-term and allow the copied evaluator as a
+temporary per-strate fallback when exact behavior is needed earlier. This round implemented the cheap
+biome query only; a full biome surface port did not fit alongside the geometry and streaming checks.
+
+### BuildHost outcome and run ledger
+
+`Tools/BuildVoxelForgeCoreHost.ps1` and `Tools/TestVoxelForgeCoreWorldHost.ps1 -TimeoutSeconds 900`
+passed. The actor test reported `streaming=1 collision=1 anchor_move=1 carve=1`; peak commandlet
+private memory was 2,997,526,528 bytes (about 2.8 GiB). No step exceeded 15 minutes, no `0xC0000142`
+retry occurred, and no new UECC folder appeared. The requested `Saved/BuildHost/HostProject/Saved/Crashes/`
+contained only its prior crash folder.
+
+| Round-3 attempt | Outcome |
+|---|---|
+| First standalone viewer capture invocation | Failed because an owner-data path with spaces was passed in the wrong form. Corrected auto-discovery invocation produced all four Core/owner B/surface captures with exit 0. |
+| `Standalone/Build.ps1 -Target All` | Core library built and symbol audit passed; viewer link failed on 12 unresolved `VoxelForgeGpuFarViewer` symbols because the script omits `GpuFieldPort.cpp`. Canonical build files were left unchanged. |
+| First expanded surface actor test | Manually stopped after repeated collision-only region compiles prevented the overly broad settled-state condition from completing. Narrowed the test to expected visual keys/hashes; final run passed. No new UECC. |
+| Origin-room sign assertion | Failed quickly because expected signs were reversed. Core uses positive=air and negative=solid; corrected assertion passed. |
+| Intermediate commandlet builds | One failed on non-exported `GetEffectiveOriginSpineRadius`; another used protected `OriginSpineRadius`. Harness now computes effective radius from settings/season data. Later UBT builds passed. |
+| Final UBT and Core world test | Passed W1/W8/W16 hashes, origin floor, B/surface coverage and paging, biome query, anchor movement, collision, and carve markers. |
+
+After the owner's rebuild, with **Use VoxelForge Core** enabled, inspect these exact places:
+
+1. At the city/surface opening, confirm one short entry reaches a finite rounded room without capsule
+   rings; stand on the floor and confirm it is flat and walkable.
+2. Continue into the normal cave room and look down: the entry should not continue as a deep shaft.
+3. Walk through the A→B landing to the B side. Check whether jagged edges/sky gaps remain after
+   nearby tiles settle. Headless key and LOD coverage is complete; a remaining artifact needs a
+   screenshot from this same view to isolate final mesh presentation.
+4. Travel to the surface strate. Wait for coarse-to-fine transition and confirm nearby detail appears.
+   The biome query identifies `Biome_Surface_Plain`, but biome-driven surface geometry is still
+   missing, so the broad surface terrain should not yet be judged as fixed.
+
+Switch-off continues through the legacy generator. The owner rebuild/editor review is the remaining
+visual check.