VoxelForge/Standalone/UNREAL_INTEGRATION_REPORT.md

Unreal Core integration report — rounds 2–4

Date: 2026-10-08
Branch: unreal/core-integration

The initial sections preserve the round-2 integration baseline. Round 3 records the owner's first visual review; the round-4 addendum below supersedes its SurfaceWorld status and adds the requested strate coverage evidence.

Result

The Unreal route remains verified in BuildHost: an AVoxelWorld with Core mode enabled matches standalone Core tile-by-tile, checks expected collision bodies, streams an entering/leaving anchor tile, applies a carve transaction, and travels to a layout containing SurfaceWorld. The round-4 coverage matrix also found that SurfaceWorld density is exact through a temporary copied-legacy evaluator in Core. Other generator archetypes and boundary transitions remain approximate or absent; the full owner requirement is not complete. Goal 3 still has only a narrow legacy-generator baseline pass, not an actor-level switch-off A/B comparison.

Core remains opt-in (bUseVoxelForgeCore=false by default). Core mode owns separate clip settings (radius 3, max level 8), uses 25 cm Core voxels and Core tile keys, and routes mesh payloads through the existing RealtimeMesh/collision path. Round 4 changed canonical Core source and the standalone JSON reader; no .uasset or owner project file was touched.

Headless AVoxelWorld evidence

Tools/TestVoxelForgeCoreWorldHost.ps1 stages the current plugin and the five copied owner world assets into BuildHost, builds the Unreal modules, and runs VoxelForgeExplore -coreworldtest=1. The commandlet resolves the staged settings/strate data and spawns a transient AVoxelWorld with Core mode enabled.

• Initial desired set: 2,226 tiles. Density, mesh, payload, topology, triangle, empty-tile and per-tile hashes match the standalone Core reference. Aggregate hashes are density 0xd528cf02858dd01d, mesh 0x747c531b4499a9a6, payload 0x5d38ea99f9c2cad0, topology 0xd9974b32dc47fc8d.
• Collision: the expected set is 125 level-0 tiles (a 5×5×5 box); all expected non-empty tiles have cooked bodies (58), and all 67 expected empty tiles are explicitly checked as no-body. The final log reports collision_ready=58; collision_no_body=318 is the actor's global no-body bookkeeping count, not the expected-box count.
• Anchor: moving the CollisionOnly anchor from Core tile (20,0,0) to (21,0,0) requests one entering tile and releases one leaving tile. FullVisual follows the same reconciliation path but has no independent assertion in this harness.
• Carve: sequence 1, digest 0xa1d628d0de1a6824, four affected keys. The carved LOD0 tile (-1,-1,-1) hashes to 0x633f3488c0800734; every affected tile is compared to standalone Core after applying the same transaction.
• Peak process memory: 2,881,925,120 bytes (approximately 2.68 GiB), below the 8 GiB cap. The run completed in seconds, below the 15-minute stop limit.

The mesh bridge copies Core vertex positions directly: the Core API returns vertices in centimetres. Inputs to Core (player/anchor/query/edit positions and brush dimensions) use 25 cm voxel conversion; high-level brush radii/extents/falloff that came from legacy 12.5 cm voxel units are multiplied by 12.5/25 to preserve their physical size. ApplyModification low-level callers supply active Core voxel units.

Switch-off baseline

The selected narrow existing test was VoxelForge.Determinism.CrossPlatformDigest, run from Tools/VoxelForgeTest.ps1 against the staged BuildHost plugin. Unreal's automation result passed with exit 0: 115,000 legacy samples, shape digest 0xB9F6E034156BDB7A, field digest 0x212DA316FBBA4401, 86,901 solid, 28,099 air, and zero NaNs. The wrapper marked its overall run failed because Unreal wrote analytics files under C:\Users\Jahni\AppData\Local\UnrealEngine\common\analytics despite the isolated user-data path and bSendUsageData=false. This was an incidental external profile write; I did not alter or remove it. The raw automation result is a legacy baseline, not a direct assertion that an actor with bUseVoxelForgeCore=false is byte-for-byte unchanged.

Files and architecture

• Source/VoxelForgeCore/VoxelForgeCore.Build.cs defines the runtime module. It validates the canonical manifest and shim inventory, uses C++20/precise FP with no PCH or unity, and exposes only Standalone/Core/include publicly.
• Source/VoxelForgeCore/Private/Manifest/ contains one include shim for each of the 18 rows in Standalone/Core/core_sources.txt. Canonical source files remain under Standalone/.
• Source/VoxelForgeCore/Private/ModuleEntry/ supplies the Unreal module entry and the isolated include of the engine CoreMinimal.h.
• VoxelForge.Build.cs and VoxelForgeEditor.Build.cs depend on VoxelForgeCore.
• Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h defines the empty standalone export macro and the UBT module export macro. No Core generation logic changed in this round.
• Source/VoxelForge/Private/VoxelForgeCoreAdapter.cpp and Source/VoxelForge/Public/VoxelForgeCoreAssetAdapter.h serialize resolved assets into schema-v1 values without passing UObjects to Core workers.
• Source/VoxelForge/Private/VoxelWorld.cpp and Public/VoxelWorld.h contain the opt-in route, Unreal task scheduler, Core tile-key/scale bridge, MPSC/epoch handling, anchor integration, and transaction edits. VoxelForgeExploreCommandlet.cpp contains the BuildHost actor proof.
• The commandlet adapter's compile scheduler still exercises the standalone compiler at worker limits 1/8/16; the runtime scheduler is the separate Unreal-task implementation above.

BuildHost evidence

Tools/BuildVoxelForgeCoreHost.ps1 stages plugin source and copied owner assets only under Saved/BuildHost/HostProject. The final UBT run completed successfully:

• UnrealEditor-VoxelForgeCore.dll and UnrealEditor-VoxelForge.dll linked in UnrealEditor Win64 Development.
• All 18 expected Core shim objects were found and audited.
• CheckCoreSymbols.ps1 reported CORE_LINK_SAFETY_PASS: 83,843 dumpbin symbol lines checked against 399 copied Unreal-style type names, with no conflicts.
• Five staged asset copies matched their source SHA-256 values:

Asset	SHA-256
DA_Settings	5D2977F57E75A63B6B73499CD6E0AA7FBBF3718CE7F70318107BF922F0819AB7
DA_Strate1	CDA1F985E589F28CA6E93A068FECC3CA92487E4AD5700F2C301C4B563E40E5F9
DA_Strate2	02F56A18CED991BAF93DFB2F69438152275E8353B5E279C1CB7DD6E079E352E2
DA_Strate3	F47437F8D156C608AA06E40C5B76716ED4A19FA0F057688E7FECC04DC976428C
DA_Strate4	279570AE3CBA7B3507269C8209A7C931EEB7A15CC3241CE07B50120996B1C656

The final logs are Saved/BuildHost/UBT-CoreIntegration.log and Saved/BuildHost/VoxelForgeCore_ue_link_safety.log.

Headless adapter evidence

Tools/TestVoxelForgeCoreAdapterHost.ps1 launches the isolated BuildHost Unreal commandlet at Normal priority. It sampled about 4.30 GiB private memory, below the 8 GiB limit. The generated JSON is retained at Saved/BuildHost/HostProject/Plugins/VoxelForge/Saved/CoreAdapterValidation/Output/owner_world.json; the commandlet log is beside it under Logs/CoreAdapterValidation.log.

For Core compile worker limits 1, 8, and 16, the validator then generated and hashed the 2,226 desired tiles serially. Each pass matched:

Hash	Expected / actual
Density	0xdb2991c73215af4c
Mesh	0x8236c5edd7fc8e4f
Payload	0x4c48fa75a543d58e
Topology	0xbea22e76b34a4dfc
Passage walkability	5,642 / 5,642

The adapter first parses the unmodified asset-derived export. The test then reparses a validation copy with the standalone CPU benchmark view settings clip_radius=3 and max_clip_level=8. The final export itself retains the asset values.

Owner hand-off and known limits

• The staged DA_Settings exports ClipRadius=6 and MaxClipLevel=6; the standalone owner JSON has clip_radius=6 and max_clip_level=8. Runtime Core mode intentionally does not read the old asset clip values; its own defaults are radius 3 and max level 8. The adapter parity test preserves the source export and applies those reference view values only to a separate validation copy.
• In the owner's Unreal editor, select the AVoxelWorld actor and enable Voxel World | Core | Use VoxelForge Core in Details. Leave Core Clip Radius = 3 and Core Max Clip Level = 8 for the first check. Save the level only if the owner wants to keep the actor setting. With the world running, expect Core terrain to stream around the player, solid LOD0 terrain to block movement, and the existing carve entry points to create a deterministic hole. Disable the switch to return to the legacy route.
• BuildHost UBT compiled the current runtime and editor modules. If the owner's editor reports a compile error, the likely integration seams to inspect first are the new reflected properties in VoxelWorld.h (UHT), the Core module dependency in VoxelForge.Build.cs, the Core/RealtimeMesh bridge in VoxelWorld.cpp, and the editor-only commandlet code. No owner-editor build was run.
• The commandlet warns that /Game/VoxelForge/Blocks/NewDataAsset is missing. /Game is project 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.
• 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.

Failed runs, retries, and crashes

No build or test exceeded the 15-minute limit. No process returned 0xC0000142, so no automatic retry was used. One new UECC-Windows-7B23387E4235BCFEDE42BC9D637E41CB_0000 was written under Saved/BuildHost/HostProject/Plugins/VoxelForge/Saved/CoreWorldValidation/User/Saved/Crashes/; its fatal log records duplicate WorldSettings creation in the transient actor-test world. The requested Saved/BuildHost/HostProject/Saved/Crashes/ contains only the older 2026-09-17 UECC-Windows-F1A3EFD5469F5DD62E68EBBACAC84376_0000.

The run history, including corrected failures, is:

Run	Outcome
Early UBT validation/build attempts 1–7	Failed in sequence on a shim-preamble regex, stale staged Build.cs, duplicated UHT source tree, missing API export/incorrect CoreMinimal and forwarding-header paths, malformed macro quoting, canonical C4456/C4668 warnings-as-errors, and editor-only FFilePath compat fields. Each was corrected; no source Binaries/, Intermediate/, or generated header was edited.
Initial successful BuildHost UBT runs	Passed after defining the module export macro, isolating the actual engine CoreMinimal include, and setting WITH_EDITORONLY_DATA=0. They established module links and the first symbol audit.
Adapter commandlet: first launch	Failed the commandlet's output-path guard because -out was outside the staged plugin Saved directory. The path was moved under BuildHost.
Adapter commandlet: DDC path	Exited 3 with a fatal error because the DDC path exceeded Unreal's 119-character limit. The staged DDC was moved to the shorter Saved/BuildHost/VFCoreAdapterDDC; no new UECC folder appeared.
Adapter commandlet: scale	Failed schema resolution with voxel_size_cm=12.5; the adapter was corrected to emit Core's standalone 25 cm scale.
Adapter commandlet: clip bounds	The original radius 6 exceeded the validation compiler's 160-million-node bound. The harness now applies the documented radius 3 override to a copy only.
Adapter commandlet: hash comparison	Generated 6,498 tiles and walkability 5,642/5,642, but hashes differed because the staged asset max level is 6 and the standalone reference is 8. The validation copy now applies max level 8.
UBT/commandlet wrapper status	Unreal logged successful results, but two Start-Process handles exposed empty exit-code fields; one commandlet fallback also looked for a marker absent from the abslog. The scripts now require UBT's Result: Succeeded or the commandlet's result 0 plus exact parity markers. Final UBT and adapter harness runs passed.
PowerShell helper checks	Two intermediate parser attempts failed while adding the UBT fallback; one parser check exposed a multiline -and in the commandlet fallback; a separate parser invocation also hit nested-shell variable expansion. These affected no Unreal run; the scripts were corrected and parsed successfully before final execution.
Staged standalone viewer build	The first launch failed before compilation because Start-Process split a path containing spaces. The corrected BuildHost run compiled the Core library and passed its symbol audit, then the viewer link failed with 12 unresolved VoxelForgeGpuFarViewer symbols: Standalone/Build.ps1 does not link the GpuFieldPort.cpp implementation still referenced by StandaloneViewer.cpp. No canonical standalone build file was edited.
Core actor commandlet: world creation	Unreal aborted on duplicate WorldSettings creation in the transient validation level. The UECC folder above contains the fatal log. World creation was changed to use the engine initialization values; the passing actor run no longer hits this fatal.
Core actor commandlet: lifecycle attempts	One run was manually stopped after BeginPlay did not run; another had no desired tiles after roughly 15,000 manual ticks. The harness was corrected to initialize actors for play, supply a transient game instance/context and GameMode, and advance GFrameCounter. Both were stopped well before 15 minutes and produced no crash.
Core actor commandlet: UBT	One quick compile failed with C2027 for incomplete AWorldSettings; adding GameFramework/WorldSettings.h fixed it.
Core world host final run	Passed after the lifecycle fixes and again after correcting high-level brush dimensions from 12.5 cm to 25 cm Core units. The pre-correction carve run also passed parity but affected 8 tiles; the final scale-correct run affects 4 and is the reported result.
RunVoxelForgeAutomationR2.ps1 switch-off attempt	Failed before launching Unreal because the expected Saved/VoxelForgeHarnessCommon.ps1 helper was absent. The later direct VoxelForgeTest.ps1 automation run executed the selected test and produced the analytics-write wrapper failure documented above.
Switch-off automation wrapper	Unreal automation itself passed VoxelForge.Determinism.CrossPlatformDigest with exit 0; the wrapper returned failure for the external common\analytics write. No retry was attempted and no crash was reported.

The standalone viewer build failure is separate from Unreal integration. The final adapter and actor passes match preserved standalone reference hashes; the Core worker-limit 1/8/16 adapter proof also retains the original passage walkability result.

Handoff status

The owner can now try the switch described above. BuildHost proves Core tile parity, expected 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.

Round 4 — strate coverage and SurfaceWorld bridge (2026-10-08)

Status

SurfaceWorld now has an exact-density compatibility route inside Core. Surface lattice hashes match the owner reference at full resolution and at the tested coarse LODs. The bridge calls the copied legacy generator for SurfaceWorld samples, including its resolved biome field and terrain operations, then applies Core edit brushes. It is deterministic in the BuildHost W1/W8/W16 matrix. This is not a native Core SurfaceWorld implementation, and the matched viewer captures still show a mesh/presentation difference. The bridge also makes Core surface tile generation about as expensive as the owner field.

The reader now retains the serialized slab, maze, shaft, and floating-island parameter structs. Parsing those values does not mean their terrain evaluators are implemented in Core.

Generator archetype probes

Each probe has its own JSON under the probe directory. The viewer comparison uses 16 LOD0 tiles per row, except where the SurfaceWorld row also reports an explicit cross-LOD run. “Changed” counts lattice samples whose density sign differs; the old/Core hashes catch magnitude differences even when that count is zero. Capture links are matched owner-field/Core frames, reduced to 640×400 JPEGs under 300 KB each.

Generator type	Core result	Owner/Core numeric evidence	Matched capture pair
TunnelNetwork	Approximate. Core extracts room/tunnel primitives and passage chains, but not the complete owner density stack.	At the owner viewer start, 686,000 LOD0 samples: 2.167784% sign changes; symmetric sampled surface distance 1.0149 m mean / 5.1468 m max; 388 unmatched samples. Log	Owner / Core
FlatPlain	Native slab field missing; generic extracted cave geometry is only an approximation. The legacy view has its slab/column structure while Core shows a cave-like passage.	686,000 LOD0 samples: 1.284548% sign changes; 0.4040 m mean / 1.1567 m max surface distance. Log	Owner / Core
CrystalChamber	Native slab and crystal-ceiling field missing; generic cave geometry is only an approximation.	686,000 LOD0 samples: 1.284548% sign changes; 0.4040 m mean / 1.1567 m max surface distance. The fixture uses the authored crystal type and its slab parameters. Log	Owner / Core
Maze	Native maze lattice and corridor field missing. Core's room/tunnel extraction is a poor approximation in this view.	686,000 LOD0 samples: 13.337026% sign changes; 1.0784 m mean / 5.9201 m max; 3,067 unmatched samples. Log	Owner / Core
SurfaceWorld	Exact density through the temporary legacy route; mesh/presentation remains approximate.	At the surface crossing, 686,000 LOD0 samples have identical hashes and zero sign changes; sampled surface distance is 0.0767 m mean / 1.0117 m max. At the matched viewer camera, LOD2 also has identical hashes across 109,744 samples; mean surface distance 0.1737 m, max 5.264 m, 63 unmatched samples. LOD0–LOD3 hashes matched in the matched-camera matrix. LOD0 log · cross-LOD logs	Owner / Core
VerticalShafts	Native shaft/ledge field missing. The current Core shape is not a shaft approximation at the probe.	686,000 LOD0 samples: 6.071137% sign changes; legacy had 3,970 sampled surface vertices while Core had none in those tiles. A center probe changed 2.368222% of signs. The walkability audit also failed 18,122/18,570 passage samples. Log	Owner / Core
FloatingIslands	Native island SDF missing. Core generates generic cave geometry instead of suspended islands.	686,000 LOD0 samples: 95.751458% sign changes; 1.4638 m mean / 5.9236 m max surface distance. The center probe changed 100% of signs. Log	Owner / Core
Underwater	Cave shape approximate; water presentation missing. Core carries no water plane/material in its mesh payload.	At a surface-field sample point, 686,000 LOD0 samples: 8.116472% sign changes; 1.1988 m mean / 5.8131 m max surface distance, with 115 unmatched samples. Log	Owner / Core

These numbers come from different authored fields and camera regions, so the percentages are evidence for each probe, not a normalized cross-type score.

Passage types and styles

The four authored styles map to four legacy passage types in VoxelStrateManager: Straight → SlopedTunnel, Worm → CrackCrevice, Spiral → SpiralDescent, and Cascading → CascadingDrops. VerticalShaft is the separate open-surface entry, not a selectable FStratePassageConfig style. Core reads the manager-generated control-point chain, radii, and floor profile, then rebuilds tapered capsules. That preserves the broad path but not the full passage density modifier.

Passage type	Style / source	Numeric evidence, 16 LOD0 tiles	Walkability audit	Capture pair
SlopedTunnel	Straight	1.585569% sign changes; 0.4532 m mean / 1.2473 m max. Log	PASS, 5,642/5,642	Owner / Core
VerticalShaft	Open-surface entry	12.102187% sign changes; 0.9802 m mean / 5.3772 m max. Log	PASS, 5,642/5,642	Owner / Core
SpiralDescent	Spiral	1.905539% sign changes; 0.4692 m mean / 2.1429 m max. Log	PASS, 1,545/1,545	Owner / Core
CascadingDrops	Cascading	1.884840% sign changes; 0.4879 m mean / 2.2203 m max. Log	FAIL, 365/1,495 solid centerline samples	Owner / Core
CrackCrevice	Worm	1.793440% sign changes; 0.4680 m mean / 2.1420 m max. Log	FAIL, 109/1,490 solid centerline samples	Owner / Core

The non-walkable Worm and Cascading probes violate the requested entrance-to-exit walkability invariant. Those styles need correction before the Core route can claim passage coverage.

Strate transitions

All three transition fixtures were compared at the generated passage crossing near the strata boundary (16 LOD0 tiles, 514,500 lattice samples each). Owner hashes change per transition, while Core returns the same hash, 0x7f9999008f887de6, for Gradient, Hard, and Interleaved. The Core representation therefore does not yet reproduce the transition field. The Core mesh remains an approximate control- point passage through the boundary.

Transition	Sign changes	Mean / max surface distance	Capture pair
Gradient	1.186395%	0.4302 m / 2.0185 m	Owner / Core
Hard	1.170262%	0.4302 m / 2.0383 m	Owner / Core
Interleaved	1.301846%	0.4622 m / 2.5725 m	Owner / Core

The captures were taken at the passage crossing, not in the solid-only boundary camera used by the first probe attempt. Numeric logs are in the probe directory.

Other terrain-changing strate inputs and implementation route

The legacy generator also reads world seed and strate bounds; FStrateGenerationParams (worm, room, tunnel, cave warp, floor, and detail fields); the archetype structs FSlabGenerationParams, FMazeGenerationParams, FSurfaceGenerationParams, FVerticalShaftParams, and FFloatingIslandParams; disturbances; weighted/probabilistic terrain-operation stacks; biome definitions and biome-map parameters; transition type/blend width; passage style/configuration and generated floor profiles; and water-level and render-side water/biome presentation data. The round-4 reader carries the typed parameter and operation assets into the standalone snapshot. SurfaceWorld's legacy fallback consumes its full density-side stack. The shape-only path still does not evaluate all of those inputs for the other archetypes.

Recommended next route, ordered by observed visual gap: implement native FloatingIslands, then native VerticalShafts and Maze, then native FlatPlain/CrystalChamber slab fields; keep the passage chain native but fix Worm/Cascading walkability; implement transition blending in the Core layer field; add Underwater's water plane as a separate render payload. Keep the current TunnelNetwork primitive route and refine its density operators. A copied-legacy evaluator is a valid temporary bridge where exact density is the priority, but the SurfaceWorld timing below shows its cost. A density fallback alone cannot create render-side water, biome materials, decorations, or atmosphere.

SurfaceWorld performance and BuildHost verification

The matched-camera CPU viewer used 1,294 tiles through LOD8. Owner legacy generation took 23.914 s wall / 188.705 worker-seconds; Core with the SurfaceWorld bridge took 23.085 s / 180.562 worker- seconds. The prior Step29 Core viewer without the bridge took 0.785 s / 2.538 worker-seconds for the same tile count, but it omitted the surface. This is not a controlled per-sample microbenchmark; it shows the bridge costs approximately the legacy field route for the complete view. Captures and logs are under core_strate_coverage.

BuildHost was rebuilt and the actor test passed with a SurfaceWorld strate. The initial W1/W8/W16 hashes are stable: density 0xccd5858289627767, mesh 0x33c4f191ee318a40, payload 0xd487ed030c6622cd, topology 0xf5f6262021a780a0. At the surface actor position, all 2,553 expected visual tiles matched standalone; 640 fine tiles compiled, 3,588 neighbour faces and 448 LOD transitions were checked, and the biome query returned Biome_Surface_Plain (index 2). Surface hashes: density 0xb80442b34787eb4e, mesh 0xfecc9327337abbfb, payload 0xca57a4e295ce0602, topology 0x7f187a07e5c19f7f. The extra loaded count (3,288) includes support/stale keys; visual keys remain complete. Full log: CoreWorldValidation.stdout.log.

The UBT host build passed. The actor test took 12m59s and peaked at 3,042,344,960 private bytes (about 2.83 GiB), below the 15-minute / 8-GiB limits. No 0xC0000142 retry occurred. The only crash folder under BuildHost is the pre-existing UECC-Windows-F1A3EFD5469F5DD62E68EBBACAC84376_0000; there was no new crash.

Round-4 failed attempts and retries

Attempt	Outcome
Surface numeric probe at viewer z = −1,024 m	Wrong vertical slice for the standalone JSON's SurfaceWorld strate; no surface triangles. Corrected to the terrain crossing near z = −400 m and matched capture camera z = −340 m.
First style matrix	The fixture changed nested asset PassageConfig while the reader consumes the duplicated top-level passage_config. All four probes therefore stayed Straight. Regenerated each fixture with both copies updated and reran.
Vertical-shaft probe invocation	Exit 2 because the loop named a JSON file that had not been generated. Reran against the original layout, which contains the open-surface VerticalShaft entry.
First LOD matrix invocation	Exit 2 because PowerShell split a computed area argument and the viewer treated surface_lod0 as a data path. Reran with explicit argument strings; LOD0–LOD3 hashes matched.
Step30 viewer build	The script printed that vswhere.exe was unavailable, then used the installed compiler toolchain; Core compile, symbol audit, and viewer link passed.

No round-4 run crashed or needed a retry. No build/test step exceeded 15 minutes. Switch-off remains the legacy route. After the owner rebuild, recheck the SurfaceWorld shoreline, hills, and biome transitions at the matched camera after fine tiles settle; also recheck the opening-room floor. The captures show the exact-density bridge improves the surface field, but water/presentation and the other missing archetypes are still open work.