measure(step2b): per-brick setup rebuilds the chunk caches -- 10x slower; live cost attributed

Editor-only brick API (<= 8^3 points per call, TunnelNetwork/Underwater op-stack routes, 1.16%
scalar fallback). Exact: 0 Q16/sign disagreements on the full 259^3 ring and the five-seed probe
set, same hash on 1 and 6 workers, reach shrink still caught (18,107 Q16 / 735 sign).
Speed: 69.19 s wall, 17.6 us/sample vs live 7.04 s, 1.65 us/sample. Stack sampler (inclusive):
BuildChunkCache 93.5%, PropagateSdfOverBox 92.5%, BuildActiveOpList 92.6% -- each brick rebuilds
the cache windows and active-op lists; EvalBlock itself is 3.6%.
Live path attribution (inclusive, 68,934 stacks): op-stack RoomGraph EvalBlock 54.4%, SDF and
spatial candidate scans ~28%, tunnel core 18.4%, passage floor segment 15.0%, structural posts
14.6%, noise octaves 2.6%, disturbances 0.6%, diff layer 0.3%.

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

CODEMAP.md

@@ -117,10 +117,10 @@ remains `0`, and lateral regions remain gated off.
 |------|------|
 | `../../VoxelForge.uplugin` | Plugin manifest. Runtime module `VoxelForge` plus the Editor-only `VoxelForgeEditor` commandlet module. Beta. |
 | `VoxelForge.Build.cs` | Deps: Core, CoreUObject, Engine, **GameplayTags**, **RealtimeMeshComponent**. |
-| `Tools/VoxelForgeTest.ps1` | The single guarded test entry point. `-Scenario canonical|owner|probe|perf|tests|surface-fall|crossing|gate-stress|visual-edit|visual-lod|visual-gap-walk|visual-gap-inject|dig-motion|parity|horizon|horizon-render|determinism|region-eval`, optional `-Build`, `-Assets owner|default`, `-Cvars`, absolute `-Out`, `-Label`, `-HorizonLevel`, `-HorizonRenderDistanceChunks`, `-ParityExportSize=32|64|128`, `-ParityExportTile=x,y,z`, and `-SharedDDC`; stages the host/assets, isolates user/DDC/config state, serializes one Unreal launch at a time, enforces the 8 GiB/30-minute guards, waits for 6 GiB free RAM before launches, and emits compact `result.json`/`summary.txt` plus full logs. Parity can render its game leg with `-EnableRender` and compares the selected export region against the exact streamed tile hashes. `visual-gap-walk` records camera-frustum surface-point coverage at 6000 cm/s; `visual-gap-inject` proves an early component hide is detected; `dig-motion` logs per-frame vertical velocity, gate, support readiness, and movement mode. `-Cvars @{ 'voxel.TestGapAuditLegacyHandoff'=1 }` replays the old visibility handoff for A/B audit baselines. Horizon traces report desired/loaded tiles, resident stream geometry, worker seconds, steady wall time, and peak private memory; `horizon-render` captures the owner view; `determinism` compares per-tile hashes across the default CRT path and `-voxel.CrtFma3=0`; `region-eval` runs the isolated step-2 lattice comparison and candidate-bin ablation.
+| `Tools/VoxelForgeTest.ps1` | The single guarded test entry point. `-Scenario canonical|owner|probe|perf|tests|surface-fall|crossing|gate-stress|visual-edit|visual-lod|visual-gap-walk|visual-gap-inject|dig-motion|parity|horizon|horizon-render|determinism|region-eval`, optional `-Build`, `-Assets owner|default`, `-Cvars`, absolute `-Out`, `-Label`, `-HorizonLevel`, `-HorizonRenderDistanceChunks`, `-ParityExportSize=32|64|128`, `-ParityExportTile=x,y,z`, `-SharedDDC`, `-SampleDensityStacks`, `-StackSampleIntervalUs`, and `-RegionHashProbe -RegionWorkers N -RegionReferenceHash HASH`; stages the host/assets, isolates user/DDC/config state, serializes one Unreal launch at a time, enforces the 8 GiB/30-minute guards, waits for 6 GiB free RAM before launches, and emits compact `result.json`/`summary.txt` plus full logs. Parity can render its game leg with `-EnableRender` and compares the selected export region against the exact streamed tile hashes. `visual-gap-walk` records camera-frustum surface-point coverage at 6000 cm/s; `visual-gap-inject` proves an early component hide is detected; `dig-motion` logs per-frame vertical velocity, gate, support readiness, and movement mode. `-Cvars @{ 'voxel.TestGapAuditLegacyHandoff'=1 }` replays the old visibility handoff for A/B audit baselines. Horizon traces report desired/loaded tiles, resident stream geometry, worker seconds, steady wall time, and peak private memory; `horizon-render` captures the owner view; `determinism` compares per-tile hashes across the default CRT path and `-voxel.CrtFma3=0`; `region-eval` compares the live path with the default-off editor brick program on the 259³ lattice and five-seed probe set; `-RegionHashProbe -RegionWorkers N -RegionReferenceHash HASH` checks a full-ring hash at another partition count. `-SampleDensityStacks` captures profiles, and `-StackSampleIntervalUs` sets the sampling interval.
 | `Public/VoxelForgeModule.h` / `Private/VoxelForgeModule.cpp` | `FVoxelForgeModule` boilerplate (Startup/Shutdown just log). |
-| `Source/VoxelForgeEditor/VoxelForgeEditor.Build.cs` / `Private/VoxelForgeExploreCommandlet.*` | Editor/commandlet-only `-run=VoxelForgeExplore`; owns bounded render/`VF_` walk/OBJ export orchestration and is not linked by Game/Shipping. Optional `-exporttilex/y/z` sets an exact L0 tile origin for controlled export/game parity; omitting all three preserves the existing center-derived origin. `-regioneval=1` runs the default-off step-2 research harness against live `GetDensityAt`. |
-| `Source/VoxelForgeEditor/Private/VoxelForgeRegionEvalExperiment.*` | Six-partition lattice driver for the commandlet-only step-2 experiment: cold 259³ timing, bitwise repeat hashes, fixed 16-bit quantized comparisons, and exact candidate-visit attribution. It calls the live final-field API in both modes; the prepared mode selects editor-only 8³ SDF candidate bins. |
+| `Source/VoxelForgeEditor/VoxelForgeEditor.Build.cs` / `Private/VoxelForgeExploreCommandlet.*` | Editor/commandlet-only `-run=VoxelForgeExplore`; owns bounded render/`VF_` walk/OBJ export orchestration and is not linked by Game/Shipping. Optional `-exporttilex/y/z` sets an exact L0 tile origin for controlled export/game parity; omitting all three preserves the existing center-derived origin. `-regioneval=1` runs the default-off step-2 research harness: full-ring and five-seed Q16 comparisons, repeat hashes, shrunk-reach falsification, cold timings, counted live fallbacks, and separate before/after stack captures when `-SampleDensityStacks` is set. `-RegionHashProbe` runs one full-ring brick evaluation and compares its raw float hash with a reference from another worker count. |
+| `Source/VoxelForgeEditor/Private/VoxelForgeRegionEvalExperiment.*` | Lattice driver with six workers by default for the commandlet-only region experiment. The live path calls `GetDensityAt` per point; the brick path groups the lattice into aligned 8³ regions and calls the editor-only `EvaluateDensityBrick` once per region, counts scalar fallback points, and compares the exact final field. The operator block uses prepared SDF candidate bins and retains canonical per-point post-stack writer order. The full-ring hash probe supports 1–32 fixed partitions to check determinism across worker counts. |
 | `Public/VoxelGeometryHash.h` | Header-only geometry digest shared by commandlet export and runtime tile-hash dump; hashes mesh counts and the vertex/normal/UV/color/triangle arrays with the historical CRC order. |
 | `Public/VoxelStats.h` / `Private/VoxelStats.cpp` | `stat VoxelForge` DWORD counters for tile classification, skipping, meshing, operator-stack verdicts, and cave-bail diagnosis. Each `Cave Bail *` counter names one guard; `Cave Bail No Stack` counts slots with no buildable stack (no definition, or a degenerate strate). |
 
@@ -363,6 +363,7 @@ This is **where terrain shape lives.**
 | `ApplyBoundarySeal` (static) | 996 | Solidifies strate top/bottom shells. |
 | `InitializeSettings` | 2691 | Copies the effective seed, spine radius, and global XY world-bound settings from `UVoxelSettings` (the season owns all three when assigned); radius 0 preserves the unbounded field. |
 | **`GetDensityAt`** | 2712 | **Entry point.** Picks strate + generator type and, on the per-chunk refetch, builds the chunk's operator stack (editor composer → cooked-season recipe → native archetype stack); evaluates it (TunnelNetwork/Underwater through the fused `GetDensityWithParams`), then adds disturbances and structural posts. Optional `OutPreEditDensity` receives the exact final procedural field immediately before the player DiffLayer tail, allowing the near-player dig cache to replay edits without regenerating the operator stack. Its ordinary one-argument behavior is unchanged. A degenerate strate has no stack and is air; `CP_*` state remains keyed by `(DensityCacheOwnerId, ChunkCoord, LayoutVersion)`. |
+| **`EvaluateDensityBrick`** | 2728 | **Editor-only, default-off research API.** Accepts a lattice region contained by one 8-voxel bin and one 32-voxel chunk. Routes once, reuses `FVoxelDensityBlockSession::FillChunk` / `EvalBlock` for supported TunnelNetwork and Underwater operator stacks, and applies the existing post-stack writers across all brick points before returning. Unsupported routes use scalar `GetDensityAt` and return their fallback count. The API is absent from non-editor builds; streaming and gameplay continue through the original scalar API. |
 | **`GetDensityWithParams`** | 3749 | TunnelNetwork pipeline (~1000 lines) — the fused evaluator of the TunnelNetwork/Underwater stack in `GetDensityAt`. See §4. ⚠️ Takes **required** `ParamsFingerprint` + `LayoutVersion` since the AUDIT §C2 fix (2026-07-28) — they go into the SDF cache key so a chunk can no longer be evaluated against a neighbour's rooms. Callers compute the CRC **once per chunk** (`CP_TunnelFP`), never per voxel. The optional `voxel.WormBlockSkip` path (default 0) uses `VF_TryGetWormBlockSkip` + a worker-local 4³ lattice-block cache to prove `|N1| >= WormThreshold` and remove both worm noise calls only; it never changes `NetworkMask` or the fallback field path. |
 | `SampleSurfaceStructuralZ` | — | **F20:** the RAW SurfaceWorld heightfield (continents+mountains+detail), BEFORE any terrain op; returns terrain Z + relief M. Cliff re-samples it at an XY offset for a cheap analytic slope. |
 | `ComputeSurfaceTerrainZ` / `ComputeSurfaceColumn` | — | SurfaceWorld heightfield → terrain Z (+ sky-cap ceiling and overhang gate per column); biome **output-blend** lerps dominant/neighbour heights (`ParamsD`/`ParamsN`/weight). **F20 surface ops** (`FSurfaceGenerationParams`, biome-selected + slope/relief-conditioned, all default off): Cliff (slope-gated STEEPENING — push height from local mean where steep ⇒ sheer walls; 4 structural resamples only when on), Terrace (relief-gated + `TerraceHardness`), LayerLines (sedimentary shelves) — pure per-column height REMAPS applied here so the single height oracle stays consistent (MC/ClassifyTile/deco/BP bridge). **Phase 2 OVERHANG** (volumetric — real jutting shelves): in the stack's `FOverhangShelfMod`, for AIR voxels in a window `(TerrainZ, TerrainZ+OverhangHeight]` above a steep slope, the heightfield is re-sampled UPHILL (toward the cliff) by a reach that GROWS with height (tiny low ⇒ air over the void, full high ⇒ borrows the far cliff rock) and unioned in ⇒ a shelf attached to the cliff, tapering out over the void with air beneath (the sketch). Per-column `OverhangAmp`(=strength·slope-gate) + unit uphill `(DirX,DirY)` resolved once in `ComputeSurfaceColumn` (gradient sampled at the REACH scale so a spot over the void can see the cliff), cached on `FSurfaceColumn`. Genuine 3D (per-voxel structural re-eval, gated to steep overhang columns). Off ⇒ byte-identical. The field-preserving LOD0 pass removes only needless temporaries/default construction; every output remains bit-identical. §8.14. |

Source/VoxelForge/Private/VoxelGenerator.cpp

@@ -641,6 +641,8 @@ thread_local int32 VoxelGenLOD::OctaveBias = 0;
 struct FVoxelDensityBlockSession
 {
     bool bActive = false;
+    bool bBatchRequested = false;
+    bool bBatchSucceeded = false;
     FIntVector Origin = FIntVector::ZeroValue;
     int32 Step = 1;
     int32 SizeX = 0;
@@ -650,6 +652,7 @@ struct FVoxelDensityBlockSession
     TArray<uint8> Valid;
     TArray<FVoxelOpSample> BlockScratch;
     TArray<int32> ActiveOps;
+    TArray<float> BatchResults;
 
     void Begin(FIntVector InOrigin, int32 InStep, int32 InSizeX, int32 InSizeY, int32 InSizeZ)
     {
@@ -665,6 +668,9 @@ struct FVoxelDensityBlockSession
             Valid.Reset();
             BlockScratch.Reset();
             ActiveOps.Reset();
+            BatchResults.Reset();
+            bBatchRequested = false;
+            bBatchSucceeded = false;
             return;
         }
 
@@ -672,6 +678,9 @@ struct FVoxelDensityBlockSession
         // (gaps, out-of-layout, degenerate strates) use the ordinary scalar path and should not
         // pay for a block scratch lattice merely because the mesher opened the scoped hand-off.
         BlockScratch.Reset();
+        BatchResults.Reset();
+        bBatchRequested = false;
+        bBatchSucceeded = false;
     }
 
     void End()
@@ -683,6 +692,9 @@ struct FVoxelDensityBlockSession
         Valid.Reset();
         BlockScratch.Reset();
         ActiveOps.Reset();
+        BatchResults.Reset();
+        bBatchRequested = false;
+        bBatchSucceeded = false;
     }
 
     int32 Index(int32 X, int32 Y, int32 Z) const
@@ -2709,6 +2721,77 @@ void UVoxelGenerator::EndDensityBlock() const
     GVoxelDensityBlockSession.End();
 }
 
+#if WITH_EDITOR
+bool UVoxelGenerator::EvaluateDensityBrick(
+    FIntVector OriginVoxels, int32 SizeX, int32 SizeY, int32 SizeZ,
+    TArray<float>& OutDensities, int32& OutFallbackSamples) const
+{
+    OutDensities.Reset();
+    OutFallbackSamples = 0;
+    const int64 SampleCount64 = static_cast<int64>(SizeX) * SizeY * SizeZ;
+    if (SizeX <= 0 || SizeY <= 0 || SizeZ <= 0
+        || SizeX > 8 || SizeY > 8 || SizeZ > 8 || SampleCount64 > 512)
+    {
+        return false;
+    }
+
+    const FIntVector Last = OriginVoxels + FIntVector(SizeX - 1, SizeY - 1, SizeZ - 1);
+    const auto SameCell = [](int32 A, int32 B, int32 CellSize)
+    {
+        return FMath::FloorToInt(static_cast<float>(A) / static_cast<float>(CellSize))
+            == FMath::FloorToInt(static_cast<float>(B) / static_cast<float>(CellSize));
+    };
+    if (!SameCell(OriginVoxels.X, Last.X, 8)
+        || !SameCell(OriginVoxels.Y, Last.Y, 8)
+        || !SameCell(OriginVoxels.Z, Last.Z, 8)
+        || !SameCell(OriginVoxels.X, Last.X, CHUNK_SIZE)
+        || !SameCell(OriginVoxels.Y, Last.Y, CHUNK_SIZE)
+        || !SameCell(OriginVoxels.Z, Last.Z, CHUNK_SIZE))
+    {
+        return false;
+    }
+
+    const int32 SampleCount = static_cast<int32>(SampleCount64);
+    BeginDensityBlock(OriginVoxels, 1, SizeX, SizeY, SizeZ);
+    GVoxelDensityBlockSession.bBatchRequested = true;
+    GVoxelDensityBlockSession.bBatchSucceeded = false;
+    GVoxelDensityBlockSession.BatchResults.SetNumUninitialized(SampleCount);
+
+    const float FirstDensity = GetDensityAt(
+        static_cast<float>(OriginVoxels.X),
+        static_cast<float>(OriginVoxels.Y),
+        static_cast<float>(OriginVoxels.Z));
+    if (GVoxelDensityBlockSession.bBatchSucceeded)
+    {
+        OutDensities.SetNumUninitialized(SampleCount);
+        FMemory::Memcpy(
+            OutDensities.GetData(), GVoxelDensityBlockSession.BatchResults.GetData(),
+            static_cast<SIZE_T>(SampleCount) * sizeof(float));
+        EndDensityBlock();
+        return OutDensities.Num() == SampleCount;
+    }
+
+    // Recipes without the editor brick port retain the canonical point evaluator. The first
+    // call already produced point zero; the remaining samples are explicit counted fallbacks.
+    GVoxelDensityBlockSession.bBatchRequested = false;
+    OutDensities.SetNumUninitialized(SampleCount);
+    OutDensities[0] = FirstDensity;
+    for (int32 Index = 1; Index < SampleCount; ++Index)
+    {
+        const int32 X = Index % SizeX;
+        const int32 Y = (Index / SizeX) % SizeY;
+        const int32 Z = Index / (SizeX * SizeY);
+        OutDensities[Index] = GetDensityAt(
+            static_cast<float>(OriginVoxels.X + X),
+            static_cast<float>(OriginVoxels.Y + Y),
+            static_cast<float>(OriginVoxels.Z + Z));
+    }
+    OutFallbackSamples = SampleCount;
+    EndDensityBlock();
+    return true;
+}
+#endif
+
 float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
                                     float* OutPreEditDensity) const
 {
@@ -2789,6 +2872,12 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         bIsGapChunk = StrateManager->IsGapChunk(ChunkCoord);
     }
 
+#if WITH_EDITOR
+    bool bEvaluateDensityBatch = false;
+    int32 BatchSampleCount = 0;
+    int32 DensityBatchCount = 1;
+    bool bBrickHasDiffMods = false;
+#endif
     if (StrateManager && bIsGapChunk)
     {
         // SOLID BEDROCK gap between two strates. The auto-carved passages still tunnel
@@ -3361,6 +3450,160 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         }
         DensityCoreTimer.End();
 
+#if WITH_EDITOR
+        // The editor region program asks this one routed sample to fill every point in the
+        // already-evaluated operator block.  Its bricks are contained by one 8-voxel research
+        // bin and one 32-voxel chunk, so the stack, params, route, and cache key above are shared.
+        BatchSampleCount = GVoxelDensityBlockSession.SizeX
+            * GVoxelDensityBlockSession.SizeY * GVoxelDensityBlockSession.SizeZ;
+        bEvaluateDensityBatch = GVoxelDensityBlockSession.bBatchRequested
+            && bUsedOpBlockSample && !bUsedFusedEvaluator && CP_UseOpStack
+            && !bIsGapChunk && StrateManager != nullptr
+            && (CP_GenType == ECaveGeneratorType::TunnelNetwork
+                || CP_GenType == ECaveGeneratorType::Underwater)
+            && GVoxelDensityBlockSession.Samples.Num() == BatchSampleCount
+            && GVoxelDensityBlockSession.BatchResults.Num() == BatchSampleCount;
+        DensityBatchCount = bEvaluateDensityBatch ? BatchSampleCount : 1;
+        bool bBrickHasDisturbanceCandidate = true;
+        bool bBrickHasPassagePostCandidate = true;
+        if (bEvaluateDensityBatch)
+        {
+            const FIntVector BrickLast = GVoxelDensityBlockSession.Origin + FIntVector(
+                (GVoxelDensityBlockSession.SizeX - 1) * GVoxelDensityBlockSession.Step,
+                (GVoxelDensityBlockSession.SizeY - 1) * GVoxelDensityBlockSession.Step,
+                (GVoxelDensityBlockSession.SizeZ - 1) * GVoxelDensityBlockSession.Step);
+            const FBox BrickBox(
+                FVector(GVoxelDensityBlockSession.Origin.X,
+                        GVoxelDensityBlockSession.Origin.Y,
+                        GVoxelDensityBlockSession.Origin.Z),
+                FVector(BrickLast.X, BrickLast.Y, BrickLast.Z));
+            bBrickHasDisturbanceCandidate = !VoxelDensityAblation::IsDisturbancesOff()
+                && VF_AnyDisturbanceCanTouchBox(
+                    BrickBox, CP_Dist, static_cast<uint32>(Seed));
+
+            const bool bAllPassagePostsOff =
+                VoxelDensityAblation::IsPassageStructuralPostsOff()
+                && VoxelDensityAblation::IsNativeFloorOff()
+                && VoxelDensityAblation::IsLandingPostsOff();
+            if (bAllPassagePostsOff)
+            {
+                bBrickHasPassagePostCandidate = false;
+            }
+            else if (!VoxelDensityAblation::IsPassageCarvingOff())
+            {
+                bBrickHasPassagePostCandidate = StrateManager->AnyPassageNearBox(
+                    BrickBox.Min, BrickBox.Max);
+            }
+            bBrickHasDiffMods = DiffLayer != nullptr && DiffLayer->HasAnyMods();
+        }
+        const bool bApplyBrickDisturbances =
+            !bEvaluateDensityBatch || bBrickHasDisturbanceCandidate;
+        const bool bApplyBrickPassagePosts =
+            !bEvaluateDensityBatch || bBrickHasPassagePostCandidate;
+#else
+        const bool bApplyBrickDisturbances = true;
+        const bool bApplyBrickPassagePosts = true;
+#endif
+        // Chunk parameters and composer/custom recipe structure are fixed by the route above.
+        // Resolve the landing writer's base once for the whole brick, including edge bricks.
+        float BrickLandingBaseDensity = CP_Dist.BaseDensity;
+#if WITH_EDITOR
+        if (CP_UseComposerRegions && CP_ComposerRegions.bHasGlobalStructuralParams)
+        {
+            BrickLandingBaseDensity = CP_ComposerRegions.BaseDensity;
+        }
+        else
+#endif
+        if (CP_UseCustomRecipe)
+        {
+            switch (CP_CustomRecipe.StructuralParamBlock)
+            {
+            case EVoxelStrateParamBlock::TunnelNetwork:
+                BrickLandingBaseDensity = CP_CustomParams.TunnelNetworkParams.BaseDensity;
+                break;
+            case EVoxelStrateParamBlock::Slab:
+                BrickLandingBaseDensity = CP_CustomParams.SlabParams.BaseDensity;
+                break;
+            case EVoxelStrateParamBlock::Maze:
+                BrickLandingBaseDensity = CP_CustomParams.MazeParams.BaseDensity;
+                break;
+            case EVoxelStrateParamBlock::Surface:
+                BrickLandingBaseDensity = CP_CustomParams.SurfaceParams.BaseDensity;
+                break;
+            case EVoxelStrateParamBlock::VerticalShaft:
+                BrickLandingBaseDensity = CP_CustomParams.VerticalShaftParams.BaseDensity;
+                break;
+            case EVoxelStrateParamBlock::FloatingIsland:
+                BrickLandingBaseDensity = CP_CustomParams.FloatingIslandParams.BaseDensity;
+                break;
+            default:
+                break;
+            }
+        }
+        else
+        {
+            switch (CP_GenType)
+            {
+            case ECaveGeneratorType::FlatPlain:
+            case ECaveGeneratorType::CrystalChamber:
+                BrickLandingBaseDensity = CP_Slab.BaseDensity;
+                break;
+            case ECaveGeneratorType::Maze:
+                BrickLandingBaseDensity = CP_Maze.BaseDensity;
+                break;
+            case ECaveGeneratorType::SurfaceWorld:
+                BrickLandingBaseDensity = CP_Surface.BaseDensity;
+                break;
+            case ECaveGeneratorType::VerticalShafts:
+                BrickLandingBaseDensity = CP_Vert.BaseDensity;
+                break;
+            case ECaveGeneratorType::FloatingIslands:
+                BrickLandingBaseDensity = CP_Float.BaseDensity;
+                break;
+            case ECaveGeneratorType::TunnelNetwork:
+            case ECaveGeneratorType::Underwater:
+            default:
+                BrickLandingBaseDensity = CP_Tunnel.BaseDensity;
+                break;
+            }
+        }
+        for (int32 DensityBatchIndex = 0;
+#if WITH_EDITOR
+             DensityBatchIndex < DensityBatchCount;
+#else
+             DensityBatchIndex < 1;
+#endif
+             ++DensityBatchIndex)
+        {
+#if WITH_EDITOR
+            if (bEvaluateDensityBatch)
+            {
+                const int32 BatchX = DensityBatchIndex % GVoxelDensityBlockSession.SizeX;
+                const int32 BatchY = (DensityBatchIndex / GVoxelDensityBlockSession.SizeX)
+                    % GVoxelDensityBlockSession.SizeY;
+                const int32 BatchZ = DensityBatchIndex
+                    / (GVoxelDensityBlockSession.SizeX * GVoxelDensityBlockSession.SizeY);
+                WorldX = static_cast<float>(GVoxelDensityBlockSession.Origin.X
+                    + BatchX * GVoxelDensityBlockSession.Step);
+                WorldY = static_cast<float>(GVoxelDensityBlockSession.Origin.Y
+                    + BatchY * GVoxelDensityBlockSession.Step);
+                WorldZ = static_cast<float>(GVoxelDensityBlockSession.Origin.Z
+                    + BatchZ * GVoxelDensityBlockSession.Step);
+
+                const FVoxelOpSample& BatchSample =
+                    GVoxelDensityBlockSession.Samples[DensityBatchIndex];
+                Result = -BatchSample.Density;
+                bUsedOpBlockSample = true;
+                bBlockHasTunnelCore = BatchSample.bHasTunnelCoreWorldEvaluation;
+                BlockTunnelCoreSDF = BatchSample.TunnelCoreWorldSDF;
+                bBlockTunnelCoreRoomFloor = BatchSample.bTunnelCoreRoomFloor;
+                bBlockHasTunnelCoreSweptFloor = BatchSample.bHasTunnelCoreSweptFloor;
+                BlockTunnelCoreSweptFloorZ = BatchSample.TunnelCoreSweptFloorZ;
+                BlockTunnelCoreSweptFloorRadius = BatchSample.TunnelCoreSweptFloorRadius;
+                bUsedFusedEvaluator = false;
+                bRoomOwnsBottomValid = false;
+            }
+#endif
         // Resolve the graph's authored floor before the disturbance pass.  The operator-stack
         // source has already computed this exact result while publishing its sample; native
         // tunnel generation uses the prepared immutable cache.  Keeping the result here means the
@@ -3420,8 +3663,11 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
             VoxelDensityProfile::EBucket::DensityDisturbances);
         const bool bProtectVerticalShaftAir =
             VoxelPassageGeometry::VerticalShaftConnectorAirMarker();
+        if (bApplyBrickDisturbances)
+        {
             ApplyDisturbances(Result, WorldX, WorldY, WorldZ, CP_Dist, (uint32)Seed,
                 bProtectVerticalShaftAir);
+        }
         DensityDisturbancesTimer.End();
 
         // A disturbance is allowed to add visual detail, but it must not refill the landing's
@@ -3432,71 +3678,7 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
             VoxelDensityProfile::EBucket::DensityStructuralPosts);
         VoxelDensityProfile::FScopedTimer StructuralTailTimer(
             VoxelDensityProfile::EBucket::StructuralTail);
-        float LandingBaseDensity = CP_Dist.BaseDensity;
-#if WITH_EDITOR
-        // A composer parent can deliberately use a different structural base than the authored
-        // definition. The landing floor was already applied by PassageCarveOp with that parent
-        // base; use the same value for this post-disturbance MC backstop or live-vs-direct stack
-        // evaluation would differ exactly on floor voxels.
-        if (CP_UseComposerRegions && CP_ComposerRegions.bHasGlobalStructuralParams)
-        {
-            LandingBaseDensity = CP_ComposerRegions.BaseDensity;
-        }
-        else
-#endif
-        if (CP_UseCustomRecipe)
-        {
-            switch (CP_CustomRecipe.StructuralParamBlock)
-            {
-            case EVoxelStrateParamBlock::TunnelNetwork:
-                LandingBaseDensity = CP_CustomParams.TunnelNetworkParams.BaseDensity;
-                break;
-            case EVoxelStrateParamBlock::Slab:
-                LandingBaseDensity = CP_CustomParams.SlabParams.BaseDensity;
-                break;
-            case EVoxelStrateParamBlock::Maze:
-                LandingBaseDensity = CP_CustomParams.MazeParams.BaseDensity;
-                break;
-            case EVoxelStrateParamBlock::Surface:
-                LandingBaseDensity = CP_CustomParams.SurfaceParams.BaseDensity;
-                break;
-            case EVoxelStrateParamBlock::VerticalShaft:
-                LandingBaseDensity = CP_CustomParams.VerticalShaftParams.BaseDensity;
-                break;
-            case EVoxelStrateParamBlock::FloatingIsland:
-                LandingBaseDensity = CP_CustomParams.FloatingIslandParams.BaseDensity;
-                break;
-            default:
-                break;
-            }
-        }
-        else
-        {
-            switch (CP_GenType)
-            {
-            case ECaveGeneratorType::FlatPlain:
-            case ECaveGeneratorType::CrystalChamber:
-                LandingBaseDensity = CP_Slab.BaseDensity;
-                break;
-            case ECaveGeneratorType::Maze:
-                LandingBaseDensity = CP_Maze.BaseDensity;
-                break;
-            case ECaveGeneratorType::SurfaceWorld:
-                LandingBaseDensity = CP_Surface.BaseDensity;
-                break;
-            case ECaveGeneratorType::VerticalShafts:
-                LandingBaseDensity = CP_Vert.BaseDensity;
-                break;
-            case ECaveGeneratorType::FloatingIslands:
-                LandingBaseDensity = CP_Float.BaseDensity;
-                break;
-            case ECaveGeneratorType::TunnelNetwork:
-            case ECaveGeneratorType::Underwater:
-            default:
-                LandingBaseDensity = CP_Tunnel.BaseDensity;
-                break;
-            }
-        }
+        const float LandingBaseDensity = BrickLandingBaseDensity;
         auto ApplyTunnelCoreShape = [&](const FTunnelCoreWorldEvaluation& Core)
         {
             if (!VoxelMath::IsFinite(Core.SDF))
@@ -3538,6 +3720,7 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
                 CP_Dist.StrateTopWorldZ, CP_Dist.StrateBottomWorldZ,
                 CP_Dist.BoundarySealThickness, LandingBaseDensity, OriginSpineRadius);
         }
+        if (bApplyBrickPassagePosts)
         {
             VoxelDensityProfile::FScopedTimer ProfileTimer(
                 VoxelDensityProfile::EBucket::PassageStructuralPosts);
@@ -3567,12 +3750,14 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
                     CP_Dist.StrateTopWorldZ, CP_Dist.StrateBottomWorldZ,
                     CP_Dist.BoundarySealThickness, LandingBaseDensity, OriginSpineRadius);
             }
+            if (bApplyBrickPassagePosts)
             {
                 VoxelDensityProfile::FScopedTimer ProfileTimer(
                     VoxelDensityProfile::EBucket::PassageLandingFloor);
                 StrateManager->ApplyPassageLandingFloorMC(
                     Result, WorldX, WorldY, WorldZ, LandingBaseDensity);
             }
+            if (bApplyBrickPassagePosts)
             {
                 VoxelDensityProfile::FScopedTimer ProfileTimer(
                     VoxelDensityProfile::EBucket::PassageLandingRoomFloor);
@@ -3647,6 +3832,7 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         // composed from the immutable construction-time profile after generic writers and the
         // graph overlap, so the legacy passage support slab can be disabled without losing the
         // floor to a disturbance refill.
+        if (bApplyBrickPassagePosts)
         {
             VoxelDensityProfile::FScopedTimer ProfileTimer(
                 VoxelDensityProfile::EBucket::PassageLandingFloor);
@@ -3655,6 +3841,13 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         }
         StructuralTailTimer.End();
         DensityStructuralPostsTimer.End();
+#if WITH_EDITOR
+            if (bEvaluateDensityBatch)
+            {
+                GVoxelDensityBlockSession.BatchResults[DensityBatchIndex] = Result;
+            }
+#endif
+        }
     }
     else
     {
@@ -3673,6 +3866,33 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         DensityCoreTimer.End();
     }
 
+#if WITH_EDITOR
+    const int32 FinalDensityBatchCount = bEvaluateDensityBatch ? BatchSampleCount : 1;
+#else
+    const int32 FinalDensityBatchCount = 1;
+#endif
+    for (int32 FinalDensityBatchIndex = 0;
+         FinalDensityBatchIndex < FinalDensityBatchCount;
+         ++FinalDensityBatchIndex)
+    {
+#if WITH_EDITOR
+        if (bEvaluateDensityBatch)
+        {
+            const int32 BatchX = FinalDensityBatchIndex % GVoxelDensityBlockSession.SizeX;
+            const int32 BatchY = (FinalDensityBatchIndex / GVoxelDensityBlockSession.SizeX)
+                % GVoxelDensityBlockSession.SizeY;
+            const int32 BatchZ = FinalDensityBatchIndex
+                / (GVoxelDensityBlockSession.SizeX * GVoxelDensityBlockSession.SizeY);
+            WorldX = static_cast<float>(GVoxelDensityBlockSession.Origin.X
+                + BatchX * GVoxelDensityBlockSession.Step);
+            WorldY = static_cast<float>(GVoxelDensityBlockSession.Origin.Y
+                + BatchY * GVoxelDensityBlockSession.Step);
+            WorldZ = static_cast<float>(GVoxelDensityBlockSession.Origin.Z
+                + BatchZ * GVoxelDensityBlockSession.Step);
+            Result = GVoxelDensityBlockSession.BatchResults[FinalDensityBatchIndex];
+            VoxelPassageGeometry::ResetVerticalShaftConnectorAirMarker();
+        }
+#endif
     // The edge is the final generated structural invariant. Passage carving is ordered before it
     // in every archetype/stack, and this MC-facing pass also covers out-of-layout air plus any
     // disturbance that might otherwise carve back into the shell. Player edits remain separate
@@ -3704,7 +3924,13 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
     {
         *OutPreEditDensity = Result;
     }
-    if (DiffLayer && DiffLayer->HasAnyMods())
+    const bool bDiffLayerHasModsForSample = DiffLayer != nullptr &&
+#if WITH_EDITOR
+        (bEvaluateDensityBatch ? bBrickHasDiffMods : DiffLayer->HasAnyMods());
+#else
+        DiffLayer->HasAnyMods();
+#endif
+    if (DiffLayer && bDiffLayerHasModsForSample)
     {
         // ── PER-CHUNK MOD SNAPSHOT ──
         // The old HasModifications + GetDensityOffset pair took the diff layer's RWLock + a TMap find
@@ -3740,6 +3966,21 @@ float UVoxelGenerator::GetDensityAt(float WorldX, float WorldY, float WorldZ,
         }
         DensityDiffLayerTimer.End();
 
+#if WITH_EDITOR
+        if (bEvaluateDensityBatch)
+        {
+            GVoxelDensityBlockSession.BatchResults[FinalDensityBatchIndex] = Result;
+        }
+#endif
+    }
+
+#if WITH_EDITOR
+    if (bEvaluateDensityBatch)
+    {
+        GVoxelDensityBlockSession.bBatchSucceeded = true;
+    }
+#endif
+
     VoxelDensityProfile::FScopedTimer DensityTailTimer(
         VoxelDensityProfile::EBucket::DensityTail);
     VoxelPassageGeometry::ResetVerticalShaftConnectorAirMarker();

Source/VoxelForge/Public/VoxelGenerator.h

@@ -180,6 +180,13 @@ public:
                            int32 SizeX, int32 SizeY, int32 SizeZ) const;
     void EndDensityBlock() const;
 
+#if WITH_EDITOR
+    /** Editor-only region-program entry point; unsupported routes report live point fallbacks. */
+    bool EvaluateDensityBrick(FIntVector OriginVoxels, int32 SizeX, int32 SizeY, int32 SizeZ,
+                              TArray<float>& OutDensities,
+                              int32& OutFallbackSamples) const;
+#endif
+
     /**
      * Prove that the mesher's core lattice is entirely solid from the cheap, structural rules
      * that own inter-strate gaps and boundary seals.  This never samples density.  It is intended

Source/VoxelForgeEditor/Private/VoxelForgeExploreCommandlet.cpp

@@ -1475,6 +1475,40 @@ struct FRegionEvalPass
     FString EndedUtc;
 };
 
+struct FRegionEvalStackSamplerSession
+{
+    bool bStarted = false;
+
+    ~FRegionEvalStackSamplerSession()
+    {
+        if (bStarted)
+        {
+            FVoxelStackSampler::Get().StopAndWrite();
+        }
+    }
+
+    bool Start(uint32 IntervalUs, const FString& OutputDirectory,
+               const TCHAR* Scenario = TEXT("region_eval_live_ring"))
+    {
+        bStarted = FVoxelStackSampler::Get().Start(
+            IntervalUs, OutputDirectory, Scenario);
+        return bStarted;
+    }
+
+    bool Stop(FVoxelStackSampler::FSummary& OutSummary)
+    {
+        if (!bStarted)
+        {
+            return false;
+        }
+        OutSummary = FVoxelStackSampler::Get().StopAndWrite();
+        bStarted = false;
+        return OutSummary.bOutputWritten
+            && OutSummary.RegisteredThreadSamples > 0
+            && OutSummary.RetainedSamples > 0;
+    }
+};
+
 int32 FindRoomGraphRecipeIndex(int32 Seed)
 {
     for (int32 Index = 0; Index < 64; ++Index)
@@ -1724,6 +1758,7 @@ bool RunRegionEvalPass(
     const FExploreArguments& BaseArguments,
     int32 Seed,
     bool bPrepared,
+    bool bBrickProgram,
     float ReachScale,
     bool bFullRing,
     const TArray<int64>* RequestedIndices,
@@ -1731,7 +1766,8 @@ bool RunRegionEvalPass(
     bool bCountCandidates,
     bool bKeepDensities,
     FRegionEvalPass& OutPass,
-    FString& OutError)
+    FString& OutError,
+    int32 RequestedWorkerCount = VoxelForgeRegionEval::WorkerCount)
 {
     OutPass = FRegionEvalPass();
     FExploreWorld World;
@@ -1773,7 +1809,7 @@ bool RunRegionEvalPass(
         bFullRing ? nullptr : &OutPass.SampleIndices,
         bFullRing, bPrepared, ReachScale,
         bKeepDensities ? &OutPass.Densities : nullptr,
-        OutPass.Timing);
+        OutPass.Timing, bBrickProgram, RequestedWorkerCount);
     OutPass.EndedUtc = FDateTime::UtcNow().ToIso8601();
     if (!bEvaluated)
     {
@@ -1799,19 +1835,27 @@ bool RunRegionEvalPass(
 TSharedRef<FJsonObject> RegionEvalTimingJson(const FRegionEvalPass& Pass, bool bPrepared)
 {
     TSharedRef<FJsonObject> Json = MakeShared<FJsonObject>();
-    Json->SetStringField(TEXT("path"), bPrepared ? TEXT("prepared_8cube_bins") : TEXT("live_GetDensityAt"));
+    Json->SetStringField(TEXT("path"), Pass.Timing.bBrickProgram
+        ? TEXT("editor_region_brick_program")
+        : (bPrepared ? TEXT("prepared_8cube_bins") : TEXT("live_GetDensityAt")));
     Json->SetStringField(TEXT("started_utc"), Pass.StartedUtc);
     Json->SetStringField(TEXT("ended_utc"), Pass.EndedUtc);
     Json->SetNumberField(TEXT("worker_count"), Pass.Timing.Workers);
     Json->SetNumberField(TEXT("observed_worker_threads"), Pass.Timing.ObservedWorkerThreads);
     Json->SetNumberField(TEXT("samples"), static_cast<double>(Pass.Timing.SampleCount));
+    Json->SetNumberField(TEXT("evaluated_brick_points"), static_cast<double>(Pass.Timing.EvaluatedSamples));
+    Json->SetNumberField(TEXT("brick_count"), static_cast<double>(Pass.Timing.BrickCount));
+    Json->SetNumberField(TEXT("fallback_points"), static_cast<double>(Pass.Timing.FallbackSamples));
+    Json->SetNumberField(TEXT("fallback_share"), Pass.Timing.FallbackShare);
     Json->SetNumberField(TEXT("world_setup_seconds_before_density_ring"), Pass.WorldPrepareSeconds);
     Json->SetNumberField(TEXT("wall_seconds"), Pass.Timing.WallSeconds);
     Json->SetNumberField(TEXT("worker_cpu_seconds"), Pass.Timing.WorkerCpuSeconds);
     Json->SetNumberField(TEXT("worker_cpu_ns_per_sample"), Pass.Timing.NanosecondsPerSample);
-    Json->SetStringField(TEXT("worker_cpu_source"), Pass.Timing.bWorkerCpuFromOsThreadTimes
-        ? TEXT("summed Windows GetThreadTimes user+kernel CPU across six fixed work partitions")
-        : TEXT("summed worker elapsed fallback; OS thread CPU counters unavailable"));
+    const FString WorkerCpuSource = Pass.Timing.bWorkerCpuFromOsThreadTimes
+        ? FString::Printf(TEXT("summed Windows GetThreadTimes user+kernel CPU across %d fixed work partitions"),
+            Pass.Timing.Workers)
+        : TEXT("summed worker elapsed fallback; OS thread CPU counters unavailable");
+    Json->SetStringField(TEXT("worker_cpu_source"), WorkerCpuSource);
     Json->SetStringField(TEXT("quantized_hash_fnv1a64"),
         FString::Printf(TEXT("%016llx"), static_cast<unsigned long long>(Pass.Timing.QuantizedHash)));
     Json->SetStringField(TEXT("raw_float_hash_fnv1a64"),
@@ -1910,8 +1954,112 @@ int32 RunRegionEval(const FString& Params)
     int32 RequestedSamples = 262144;
     FParse::Value(*Params, TEXT("regionsamples="), RequestedSamples);
     RequestedSamples = FMath::Clamp(RequestedSamples, 32768, 1000000);
+    int32 RequestedWorkerCount = VoxelForgeRegionEval::WorkerCount;
+    FParse::Value(*Params, TEXT("regionworkers="), RequestedWorkerCount);
+    RequestedWorkerCount = FMath::Clamp(RequestedWorkerCount, 1, 32);
     IFileManager::Get().MakeDirectory(*Arguments.OutDirectory, true);
 
+    if (FParse::Param(*Params, TEXT("regionhashprobe")))
+    {
+        FRegionEvalStackSamplerSession WorkerHashStackSampler;
+        if (Arguments.bSampleStacks
+            && !WorkerHashStackSampler.Start(
+                Arguments.SampleStacksIntervalUs, Arguments.OutDirectory,
+                TEXT("region_eval_brick_worker_hash")))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] worker hash stack sampler could not be started."));
+            return 2;
+        }
+
+        FRegionEvalPass WorkerHashPass;
+        const bool bHashPassSucceeded = RunRegionEvalPass(
+                Arguments, 1337, true, true, 1.0f, true, nullptr,
+                RequestedSamples, false, true, WorkerHashPass, Error,
+                RequestedWorkerCount);
+        bool bStackCaptureSucceeded = true;
+        if (Arguments.bSampleStacks)
+        {
+            FVoxelStackSampler::FSummary StackSummary;
+            bStackCaptureSucceeded = WorkerHashStackSampler.Stop(StackSummary);
+            UE_LOG(LogTemp, Display,
+                TEXT("[VoxelForgeRegionEval] worker-hash stack capture registered=%llu retained=%llu "
+                     "raw=%s summary=%s"),
+                static_cast<unsigned long long>(StackSummary.RegisteredThreadSamples),
+                static_cast<unsigned long long>(StackSummary.RetainedSamples),
+                *StackSummary.RawSamplesPath, *StackSummary.SummaryPath);
+        }
+        if (!bHashPassSucceeded || !bStackCaptureSucceeded)
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] worker hash probe failed: %s"),
+                Error.IsEmpty() ? TEXT("stack capture retained no worker samples") : *Error);
+            return 2;
+        }
+
+        FString ReferenceRawHash;
+        FParse::Value(*Params, TEXT("regionreferencehash="), ReferenceRawHash);
+        const FString ActualRawHash = FString::Printf(TEXT("%016llx"),
+            static_cast<unsigned long long>(WorkerHashPass.Timing.RawFloatHash));
+        const bool bHasReferenceHash = !ReferenceRawHash.IsEmpty();
+        const bool bMatchesReference = bHasReferenceHash
+            && ActualRawHash.Equals(ReferenceRawHash, ESearchCase::IgnoreCase);
+        const bool bProbePassed = bMatchesReference
+            && WorkerHashPass.Timing.SampleCount
+                == static_cast<int64>(VoxelForgeRegionEval::RingDimension)
+                    * VoxelForgeRegionEval::RingDimension * VoxelForgeRegionEval::RingDimension
+            && WorkerHashPass.Timing.SaturatedSamples == 0
+            && WorkerHashPass.Timing.NonFiniteSamples == 0;
+
+        TSharedRef<FJsonObject> ProbeReport = MakeShared<FJsonObject>();
+        ProbeReport->SetBoolField(TEXT("pass"), bProbePassed);
+        ProbeReport->SetBoolField(TEXT("worker_count_hash_probe"), true);
+        ProbeReport->SetNumberField(TEXT("worker_count"), WorkerHashPass.Timing.Workers);
+        ProbeReport->SetNumberField(TEXT("observed_worker_threads"),
+            WorkerHashPass.Timing.ObservedWorkerThreads);
+        ProbeReport->SetNumberField(TEXT("samples"), WorkerHashPass.Timing.SampleCount);
+        ProbeReport->SetNumberField(TEXT("brick_count"), WorkerHashPass.Timing.BrickCount);
+        ProbeReport->SetNumberField(TEXT("fallback_points"), WorkerHashPass.Timing.FallbackSamples);
+        ProbeReport->SetNumberField(TEXT("fallback_share"), WorkerHashPass.Timing.FallbackShare);
+        ProbeReport->SetNumberField(TEXT("wall_seconds"), WorkerHashPass.Timing.WallSeconds);
+        ProbeReport->SetNumberField(TEXT("worker_cpu_seconds"), WorkerHashPass.Timing.WorkerCpuSeconds);
+        ProbeReport->SetStringField(TEXT("reference_raw_float_hash_fnv1a64"), ReferenceRawHash);
+        ProbeReport->SetStringField(TEXT("raw_float_hash_fnv1a64"), ActualRawHash);
+        ProbeReport->SetBoolField(TEXT("matches_reference"), bMatchesReference);
+
+        FString ProbeJsonText;
+        TSharedRef<TJsonWriter<>> ProbeWriter = TJsonWriterFactory<>::Create(&ProbeJsonText);
+        if (!FJsonSerializer::Serialize(ProbeReport, ProbeWriter)
+            || !FFileHelper::SaveStringToFile(
+                ProbeJsonText, *FPaths::Combine(Arguments.OutDirectory, TEXT("region_eval.json")),
+                FFileHelper::EEncodingOptions::ForceUTF8WithoutBOM))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] could not write worker hash probe report."));
+            return 2;
+        }
+        UE_LOG(LogTemp, Display,
+            TEXT("[VoxelForgeRegionEval] worker hash probe workers=%d observed=%d samples=%lld "
+                 "raw=%s reference_match=%s report=%s"),
+            WorkerHashPass.Timing.Workers, WorkerHashPass.Timing.ObservedWorkerThreads,
+            static_cast<long long>(WorkerHashPass.Timing.SampleCount), *ActualRawHash,
+            bMatchesReference ? TEXT("yes") : TEXT("no"),
+            *FPaths::Combine(Arguments.OutDirectory, TEXT("region_eval.json")));
+        return bProbePassed ? 0 : 2;
+    }
+
+    // Region-eval returns before the normal Explore sampler setup. Capture only its two cold live
+    // ring trials so prepared-path and multi-seed work cannot pollute the baseline attribution.
+    FRegionEvalStackSamplerSession StackSamplerSession;
+    if (Arguments.bSampleStacks
+        && !StackSamplerSession.Start(
+            Arguments.SampleStacksIntervalUs, Arguments.OutDirectory))
+    {
+        UE_LOG(LogTemp, Error,
+            TEXT("[VoxelForgeRegionEval] requested stack sampler could not be started."));
+        return 2;
+    }
+
     const int32 Seeds[] = { 1337, 7331, 19427, 30241, 41011 };
     TArray<TSharedPtr<FJsonValue>> SeedReports;
     TArray<TSharedPtr<FJsonValue>> OldTimingReports;
@@ -1938,8 +2086,8 @@ int32 RunRegionEval(const FString& Params)
     {
         FRegionEvalPass Pass;
         const bool bOk = RunRegionEvalPass(
-            Arguments, Seeds[0], false, 1.0f, true, nullptr,
-            RequestedSamples, Trial == 0, true, Pass, Error);
+            Arguments, Seeds[0], false, false, 1.0f, true, nullptr,
+            RequestedSamples, Trial == 0 && !Arguments.bSampleStacks, true, Pass, Error);
         if (!bOk)
         {
             UE_LOG(LogTemp, Error, TEXT("[VoxelForgeRegionEval] live full-ring trial failed: %s"), *Error);
@@ -1964,6 +2112,22 @@ int32 RunRegionEval(const FString& Params)
         }
         OldTimingReports.Add(MakeShared<FJsonValueObject>(RegionEvalTimingJson(Pass, false)));
     }
+    if (Arguments.bSampleStacks)
+    {
+        FVoxelStackSampler::FSummary StackSummary;
+        if (!StackSamplerSession.Stop(StackSummary))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] stack capture retained no live-ring worker samples."));
+            return 2;
+        }
+        UE_LOG(LogTemp, Display,
+            TEXT("[VoxelForgeRegionEval] live-ring stack capture registered=%llu retained=%llu "
+                 "raw=%s summary=%s"),
+            static_cast<unsigned long long>(StackSummary.RegisteredThreadSamples),
+            static_cast<unsigned long long>(StackSummary.RetainedSamples),
+            *StackSummary.RawSamplesPath, *StackSummary.SummaryPath);
+    }
     if (PrimarySampleIndices.IsEmpty())
     {
         UE_LOG(LogTemp, Error, TEXT("[VoxelForgeRegionEval] primary statistical sample set is empty."));
@@ -1974,7 +2138,7 @@ int32 RunRegionEval(const FString& Params)
     {
         FRegionEvalPass Pass;
         const bool bOk = RunRegionEvalPass(
-            Arguments, Seeds[0], true, 1.0f, true, nullptr,
+            Arguments, Seeds[0], true, true, 1.0f, true, nullptr,
             RequestedSamples, Trial == 0, true, Pass, Error);
         if (!bOk)
         {
@@ -2003,11 +2167,46 @@ int32 RunRegionEval(const FString& Params)
     // Statistical fixed-lattice comparisons across four additional independent seeds. The sample
     // set is a deterministic affine permutation of the entire 259^3 ring plus dense strata,
     // passage-floor, landing, carve, and fill probes.
+    if (Arguments.bSampleStacks)
+    {
+        FRegionEvalStackSamplerSession BrickStackSamplerSession;
+        if (!BrickStackSamplerSession.Start(
+                Arguments.SampleStacksIntervalUs, Arguments.OutDirectory,
+                TEXT("region_eval_brick_ring")))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] brick stack sampler could not be started."));
+            return 2;
+        }
+        FRegionEvalPass ProfiledBrickPass;
+        if (!RunRegionEvalPass(
+                Arguments, Seeds[0], true, true, 1.0f, true, nullptr,
+                RequestedSamples, false, false, ProfiledBrickPass, Error))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] brick attribution run failed: %s"), *Error);
+            return 2;
+        }
+        FVoxelStackSampler::FSummary BrickStackSummary;
+        if (!BrickStackSamplerSession.Stop(BrickStackSummary))
+        {
+            UE_LOG(LogTemp, Error,
+                TEXT("[VoxelForgeRegionEval] brick stack capture retained no worker samples."));
+            return 2;
+        }
+        UE_LOG(LogTemp, Display,
+            TEXT("[VoxelForgeRegionEval] brick stack capture registered=%llu retained=%llu "
+                 "raw=%s summary=%s"),
+            static_cast<unsigned long long>(BrickStackSummary.RegisteredThreadSamples),
+            static_cast<unsigned long long>(BrickStackSummary.RetainedSamples),
+            *BrickStackSummary.RawSamplesPath, *BrickStackSummary.SummaryPath);
+    }
+
     for (int32 SeedIndex = 1; SeedIndex < UE_ARRAY_COUNT(Seeds); ++SeedIndex)
     {
         FRegionEvalPass OldPass;
         if (!RunRegionEvalPass(
-                Arguments, Seeds[SeedIndex], false, 1.0f, false, nullptr,
+                Arguments, Seeds[SeedIndex], false, false, 1.0f, false, nullptr,
                 RequestedSamples, true, true, OldPass, Error))
         {
             UE_LOG(LogTemp, Error, TEXT("[VoxelForgeRegionEval] seed %d live sample failed: %s"),
@@ -2017,7 +2216,7 @@ int32 RunRegionEval(const FString& Params)
         CollectGarbage(GARBAGE_COLLECTION_KEEPFLAGS);
         FRegionEvalPass NewPass;
         if (!RunRegionEvalPass(
-                Arguments, Seeds[SeedIndex], true, 1.0f, false, &OldPass.SampleIndices,
+                Arguments, Seeds[SeedIndex], true, true, 1.0f, false, &OldPass.SampleIndices,
                 RequestedSamples, true, true, NewPass, Error))
         {
             UE_LOG(LogTemp, Error, TEXT("[VoxelForgeRegionEval] seed %d prepared sample failed: %s"),
@@ -2051,7 +2250,7 @@ int32 RunRegionEval(const FString& Params)
     // commandlet pass and every worker resets it to 1.0 afterward.
     FRegionEvalPass ShrunkPass;
     if (!RunRegionEvalPass(
-            Arguments, Seeds[0], true, 0.50f, false, &PrimarySampleIndices,
+            Arguments, Seeds[0], true, true, 0.50f, false, &PrimarySampleIndices,
             RequestedSamples, false, true, ShrunkPass, Error))
     {
         UE_LOG(LogTemp, Error, TEXT("[VoxelForgeRegionEval] deliberate reach-shrink run failed: %s"), *Error);
@@ -2110,7 +2309,7 @@ int32 RunRegionEval(const FString& Params)
     TSharedRef<FJsonObject> Report = MakeShared<FJsonObject>();
     Report->SetNumberField(TEXT("schema_version"), 1);
     Report->SetStringField(TEXT("route"), TEXT("editor-only explore commandlet; required Unreal composer, manager, and generator types"));
-    Report->SetStringField(TEXT("evaluator"), TEXT("live GetDensityAt final field with editor-only 8^3 SDF room/join/tunnel candidate bins"));
+    Report->SetStringField(TEXT("evaluator"), TEXT("editor-only 8^3 region brick program; block-evaluated composer operator core and canonical per-point final-field writers; unsupported routes use counted live fallbacks"));
     Report->SetStringField(TEXT("comparison_quantization"), TEXT("signed int16; round ties away from zero; multiply density by 16; saturate outside [-2048, 2047.9375] density voxels"));
     Report->SetNumberField(TEXT("worker_count"), VoxelForgeRegionEval::WorkerCount);
     Report->SetNumberField(TEXT("ring_dimension"), VoxelForgeRegionEval::RingDimension);

Source/VoxelForgeEditor/Private/VoxelForgeRegionEvalExperiment.cpp

@@ -5,6 +5,7 @@
 #include "VoxelCaveMorphology.h"
 #include "VoxelDensityProfile.h"
 #include "VoxelGenerator.h"
+#include "VoxelStackSampler.h"
 #include "HAL/PlatformTLS.h"
 
 #if PLATFORM_WINDOWS
@@ -73,6 +74,24 @@ namespace VoxelForgeRegionEval
         {
             return static_cast<int64>(Dimension) * Dimension * Dimension;
         }
+
+        struct FRegionBrickSample
+        {
+            int32 LocalIndex = 0;
+            int32 OutputIndex = 0;
+        };
+
+        struct FRegionBrick
+        {
+            FIntVector Origin = FIntVector::ZeroValue;
+            int32 SizeX = 0;
+            int32 SizeY = 0;
+            int32 SizeZ = 0;
+            int32 LatticeX = 0;
+            int32 LatticeY = 0;
+            int32 LatticeZ = 0;
+            TArray<FRegionBrickSample> RequestedSamples;
+        };
     }
 
     int64 LinearIndex(int32 X, int32 Y, int32 Z, int32 Dimension)
@@ -128,9 +147,13 @@ namespace VoxelForgeRegionEval
         bool bPrepared,
         float ReachScale,
         TArray<float>* OutDensities,
-        FTiming& OutTiming)
+        FTiming& OutTiming,
+        bool bBrickProgram,
+        int32 RequestedWorkerCount)
     {
         OutTiming = FTiming();
+        const int32 NumWorkers = FMath::Clamp(RequestedWorkerCount, 1, 32);
+        OutTiming.Workers = NumWorkers;
         if (Dimension <= 0 || Dimension > 4096
             || (bFullRing && SampleIndices != nullptr)
             || (!bFullRing && SampleIndices == nullptr))
@@ -145,6 +168,94 @@ namespace VoxelForgeRegionEval
             return false;
         }
         const double StartSeconds = FPlatformTime::Seconds();
+        TArray<FRegionBrick> Bricks;
+        TArray<int32> WorkBricks;
+        if (bBrickProgram)
+        {
+            const int32 LastX = OriginVoxels.X + Dimension - 1;
+            const int32 LastY = OriginVoxels.Y + Dimension - 1;
+            const int32 LastZ = OriginVoxels.Z + Dimension - 1;
+            const int32 FirstCellX = FMath::FloorToInt(static_cast<float>(OriginVoxels.X) / 8.0f);
+            const int32 FirstCellY = FMath::FloorToInt(static_cast<float>(OriginVoxels.Y) / 8.0f);
+            const int32 FirstCellZ = FMath::FloorToInt(static_cast<float>(OriginVoxels.Z) / 8.0f);
+            const int32 LastCellX = FMath::FloorToInt(static_cast<float>(LastX) / 8.0f);
+            const int32 LastCellY = FMath::FloorToInt(static_cast<float>(LastY) / 8.0f);
+            const int32 LastCellZ = FMath::FloorToInt(static_cast<float>(LastZ) / 8.0f);
+            const int32 CellsX = LastCellX - FirstCellX + 1;
+            const int32 CellsY = LastCellY - FirstCellY + 1;
+            const int32 CellsZ = LastCellZ - FirstCellZ + 1;
+            Bricks.Reserve(CellsX * CellsY * CellsZ);
+            for (int32 CellZ = FirstCellZ; CellZ <= LastCellZ; ++CellZ)
+            for (int32 CellY = FirstCellY; CellY <= LastCellY; ++CellY)
+            for (int32 CellX = FirstCellX; CellX <= LastCellX; ++CellX)
+            {
+                FRegionBrick& Brick = Bricks.AddDefaulted_GetRef();
+                const int32 CellMinX = CellX * 8;
+                const int32 CellMinY = CellY * 8;
+                const int32 CellMinZ = CellZ * 8;
+                Brick.Origin = FIntVector(
+                    FMath::Max(CellMinX, OriginVoxels.X),
+                    FMath::Max(CellMinY, OriginVoxels.Y),
+                    FMath::Max(CellMinZ, OriginVoxels.Z));
+                const int32 EndX = FMath::Min(CellMinX + 8, LastX + 1);
+                const int32 EndY = FMath::Min(CellMinY + 8, LastY + 1);
+                const int32 EndZ = FMath::Min(CellMinZ + 8, LastZ + 1);
+                Brick.SizeX = EndX - Brick.Origin.X;
+                Brick.SizeY = EndY - Brick.Origin.Y;
+                Brick.SizeZ = EndZ - Brick.Origin.Z;
+                Brick.LatticeX = Brick.Origin.X - OriginVoxels.X;
+                Brick.LatticeY = Brick.Origin.Y - OriginVoxels.Y;
+                Brick.LatticeZ = Brick.Origin.Z - OriginVoxels.Z;
+            }
+
+            if (bFullRing)
+            {
+                WorkBricks.Reserve(Bricks.Num());
+                for (int32 BrickIndex = 0; BrickIndex < Bricks.Num(); ++BrickIndex)
+                {
+                    WorkBricks.Add(BrickIndex);
+                }
+            }
+            else
+            {
+                WorkBricks.Reserve(Bricks.Num());
+                for (int32 OutputIndex = 0; OutputIndex < SampleIndices->Num(); ++OutputIndex)
+                {
+                    const int64 LatticeIndex = (*SampleIndices)[OutputIndex];
+                    if (LatticeIndex < 0 || LatticeIndex >= TotalLatticeSamples)
+                    {
+                        return false;
+                    }
+                    const int32 X = static_cast<int32>(LatticeIndex % Dimension);
+                    const int32 Y = static_cast<int32>((LatticeIndex / Dimension) % Dimension);
+                    const int32 Z = static_cast<int32>(LatticeIndex
+                        / (static_cast<int64>(Dimension) * Dimension));
+                    const int32 WorldX = OriginVoxels.X + X;
+                    const int32 WorldY = OriginVoxels.Y + Y;
+                    const int32 WorldZ = OriginVoxels.Z + Z;
+                    const int32 CellX = FMath::FloorToInt(static_cast<float>(WorldX) / 8.0f);
+                    const int32 CellY = FMath::FloorToInt(static_cast<float>(WorldY) / 8.0f);
+                    const int32 CellZ = FMath::FloorToInt(static_cast<float>(WorldZ) / 8.0f);
+                    const int32 BrickIndex = ((CellZ - FirstCellZ) * CellsY
+                        + (CellY - FirstCellY)) * CellsX + (CellX - FirstCellX);
+                    FRegionBrick& Brick = Bricks[BrickIndex];
+                    const int32 LocalX = WorldX - Brick.Origin.X;
+                    const int32 LocalY = WorldY - Brick.Origin.Y;
+                    const int32 LocalZ = WorldZ - Brick.Origin.Z;
+                    FRegionBrickSample& BrickSample = Brick.RequestedSamples.AddDefaulted_GetRef();
+                    BrickSample.LocalIndex =
+                        (LocalZ * Brick.SizeY + LocalY) * Brick.SizeX + LocalX;
+                    BrickSample.OutputIndex = OutputIndex;
+                }
+                for (int32 BrickIndex = 0; BrickIndex < Bricks.Num(); ++BrickIndex)
+                {
+                    if (!Bricks[BrickIndex].RequestedSamples.IsEmpty())
+                    {
+                        WorkBricks.Add(BrickIndex);
+                    }
+                }
+            }
+        }
         if (OutDensities != nullptr)
         {
             if (SampleCount > MAX_int32)
@@ -157,24 +268,78 @@ namespace VoxelForgeRegionEval
         const int32 OriginX = OriginVoxels.X;
         const int32 OriginY = OriginVoxels.Y;
         const int32 OriginZ = OriginVoxels.Z;
-        double WorkerSeconds[WorkerCount] = {};
-        double WorkerCpuSeconds[WorkerCount] = {};
-        bool WorkerCpuFromOsThreadTimes[WorkerCount] = {};
+        TArray<double> WorkerSeconds;
+        TArray<double> WorkerCpuSeconds;
+        TArray<uint8> WorkerCpuFromOsThreadTimes;
+        TArray<uint32> WorkerThreadIds;
+        TArray<uint64> WorkerNonFinite;
+        TArray<uint64> WorkerEvaluatedSamples;
+        TArray<uint64> WorkerFallbackSamples;
+        TArray<uint64> WorkerEvaluationFailures;
+        WorkerSeconds.SetNumZeroed(NumWorkers);
+        WorkerCpuSeconds.SetNumZeroed(NumWorkers);
+        WorkerCpuFromOsThreadTimes.SetNumZeroed(NumWorkers);
+        WorkerThreadIds.SetNumZeroed(NumWorkers);
+        WorkerNonFinite.SetNumZeroed(NumWorkers);
+        WorkerEvaluatedSamples.SetNumZeroed(NumWorkers);
+        WorkerFallbackSamples.SetNumZeroed(NumWorkers);
+        WorkerEvaluationFailures.SetNumZeroed(NumWorkers);
         bool bAllWorkerCpuFromOsThreadTimes = true;
-        uint32 WorkerThreadIds[WorkerCount] = {};
-        uint64 WorkerNonFinite[WorkerCount] = {};
-        ParallelFor(WorkerCount, [&](int32 WorkerIndex)
+        ParallelFor(NumWorkers, [&](int32 WorkerIndex)
         {
+            // Region-eval workers are not launched through AVoxelWorld::LoadTile, so they do not
+            // inherit its task-level sampler registration. Keep this registration scoped to the
+            // research worker partition; with sampling disabled it is one relaxed flag load.
+            FScopedVoxelStackRegistration StackRegistration;
             VoxelCaveMorphology::SetResearchBrickBinningEnabled(bPrepared);
             VoxelCaveMorphology::SetResearchBrickRoomReachScale(ReachScale);
             WorkerThreadIds[WorkerIndex] = FPlatformTLS::GetCurrentThreadId();
-            const int64 Begin = (SampleCount * WorkerIndex) / WorkerCount;
-            const int64 End = (SampleCount * (WorkerIndex + 1)) / WorkerCount;
+            const int64 WorkCount = bBrickProgram ? WorkBricks.Num() : SampleCount;
+            const int64 Begin = (WorkCount * WorkerIndex) / NumWorkers;
+            const int64 End = (WorkCount * (WorkerIndex + 1)) / NumWorkers;
             const double WorkerStart = FPlatformTime::Seconds();
             double WorkerCpuStart = 0.0;
             const bool bHaveWorkerCpuStart = GetCurrentThreadCpuSeconds(WorkerCpuStart);
+            TArray<float> BrickDensities;
             for (int64 OutputIndex = Begin; OutputIndex < End; ++OutputIndex)
             {
+                if (bBrickProgram)
+                {
+                    const FRegionBrick& Brick = Bricks[WorkBricks[static_cast<int32>(OutputIndex)]];
+                    int32 BrickFallbackSamples = 0;
+                    if (!Generator.EvaluateDensityBrick(
+                            Brick.Origin, Brick.SizeX, Brick.SizeY, Brick.SizeZ,
+                            BrickDensities, BrickFallbackSamples)
+                        || BrickDensities.Num() != Brick.SizeX * Brick.SizeY * Brick.SizeZ)
+                    {
+                        ++WorkerEvaluationFailures[WorkerIndex];
+                        continue;
+                    }
+                    const int32 BrickSampleCount = BrickDensities.Num();
+                    WorkerEvaluatedSamples[WorkerIndex] += static_cast<uint64>(BrickSampleCount);
+                    WorkerFallbackSamples[WorkerIndex] += static_cast<uint64>(BrickFallbackSamples);
+                    if (bFullRing && OutDensities != nullptr)
+                    {
+                        for (int32 Bz = 0; Bz < Brick.SizeZ; ++Bz)
+                        for (int32 By = 0; By < Brick.SizeY; ++By)
+                        for (int32 Bx = 0; Bx < Brick.SizeX; ++Bx)
+                        {
+                            const int32 LocalIndex = (Bz * Brick.SizeY + By) * Brick.SizeX + Bx;
+                            const int64 LatticeIndex = LinearIndex(
+                                Brick.LatticeX + Bx, Brick.LatticeY + By,
+                                Brick.LatticeZ + Bz, Dimension);
+                            (*OutDensities)[static_cast<int32>(LatticeIndex)] = BrickDensities[LocalIndex];
+                        }
+                    }
+                    else if (OutDensities != nullptr)
+                    {
+                        for (const FRegionBrickSample& Sample : Brick.RequestedSamples)
+                        {
+                            (*OutDensities)[Sample.OutputIndex] = BrickDensities[Sample.LocalIndex];
+                        }
+                    }
+                    continue;
+                }
                 const int64 LatticeIndex = bFullRing
                     ? OutputIndex : (*SampleIndices)[static_cast<int32>(OutputIndex)];
                 if (LatticeIndex < 0 || LatticeIndex >= TotalLatticeSamples)
@@ -212,11 +377,20 @@ namespace VoxelForgeRegionEval
 
         OutTiming.WallSeconds = FPlatformTime::Seconds() - StartSeconds;
         OutTiming.SampleCount = SampleCount;
-        for (int32 WorkerIndex = 0; WorkerIndex < WorkerCount; ++WorkerIndex)
+        OutTiming.bBrickProgram = bBrickProgram;
+        OutTiming.BrickCount = bBrickProgram ? WorkBricks.Num() : 0;
+        for (int32 WorkerIndex = 0; WorkerIndex < NumWorkers; ++WorkerIndex)
         {
             OutTiming.WorkerCpuSeconds += WorkerCpuSeconds[WorkerIndex];
-            bAllWorkerCpuFromOsThreadTimes &= WorkerCpuFromOsThreadTimes[WorkerIndex];
+            bAllWorkerCpuFromOsThreadTimes &= WorkerCpuFromOsThreadTimes[WorkerIndex] != 0;
             OutTiming.NonFiniteSamples += WorkerNonFinite[WorkerIndex];
+            OutTiming.EvaluatedSamples += bBrickProgram
+                ? static_cast<int64>(WorkerEvaluatedSamples[WorkerIndex]) : 0;
+            OutTiming.FallbackSamples += static_cast<int64>(WorkerFallbackSamples[WorkerIndex]);
+            if (WorkerEvaluationFailures[WorkerIndex] != 0)
+            {
+                return false;
+            }
             bool bAlreadyCounted = false;
             for (int32 PriorWorker = 0; PriorWorker < WorkerIndex; ++PriorWorker)
             {
@@ -225,6 +399,11 @@ namespace VoxelForgeRegionEval
             OutTiming.ObservedWorkerThreads += bAlreadyCounted ? 0 : 1;
         }
         OutTiming.bWorkerCpuFromOsThreadTimes = bAllWorkerCpuFromOsThreadTimes;
+        if (OutTiming.EvaluatedSamples > 0)
+        {
+            OutTiming.FallbackShare = static_cast<double>(OutTiming.FallbackSamples)
+                / static_cast<double>(OutTiming.EvaluatedSamples);
+        }
         OutTiming.NanosecondsPerSample = OutTiming.SampleCount > 0
             ? OutTiming.WorkerCpuSeconds * 1.0e9 / static_cast<double>(OutTiming.SampleCount)
             : 0.0;

Source/VoxelForgeEditor/Private/VoxelForgeRegionEvalExperiment.h

@@ -17,10 +17,15 @@ namespace VoxelForgeRegionEval
         int32 Workers = WorkerCount;
         int32 ObservedWorkerThreads = 0;
         int64 SampleCount = 0;
+        int64 EvaluatedSamples = 0;
+        int64 BrickCount = 0;
+        int64 FallbackSamples = 0;
+        double FallbackShare = 0.0;
         double WallSeconds = 0.0;
         double WorkerCpuSeconds = 0.0;
         double NanosecondsPerSample = 0.0;
         bool bWorkerCpuFromOsThreadTimes = false;
+        bool bBrickProgram = false;
         uint64 QuantizedHash = 0;
         uint64 RawFloatHash = 0;
         uint64 SaturatedSamples = 0;
@@ -67,7 +72,9 @@ namespace VoxelForgeRegionEval
         bool bPrepared,
         float ReachScale,
         TArray<float>* OutDensities,
-        FTiming& OutTiming);
+        FTiming& OutTiming,
+        bool bBrickProgram = false,
+        int32 RequestedWorkerCount = WorkerCount);
 
     /** Count exact room/tunnel/core/passage candidate visits with instrumentation enabled. */
     FCandidateVisits CountCandidates(

Tools/VoxelForgeTest.ps1

@@ -4,6 +4,13 @@ param(
     [string]$Scenario = 'canonical',
     [switch]$Build,
     [switch]$EnableRender,
+    [switch]$SampleDensityStacks,
+    [ValidateRange(1, 1000000)]
+    [int]$StackSampleIntervalUs = 1000,
+    [switch]$RegionHashProbe,
+    [ValidateRange(1, 32)]
+    [int]$RegionWorkers = 6,
+    [string]$RegionReferenceHash = '',
     [ValidateSet('owner', 'default')]
     [string]$Assets = 'owner',
     [hashtable]$Cvars = @{},
@@ -1430,6 +1437,17 @@ try {
             $args = New-CommonArguments 'commandlet' $regionLog (Merge-Cvars $baseCvars)
             $args += New-CommandletArguments $commandletOut 'walk,export' ($Assets -eq 'owner') $false 128
             $args += @('-regioneval', '-regionsamples=262144')
+            if ($SampleDensityStacks) { $args += "-samplestacks=$StackSampleIntervalUs" }
+            if ($RegionHashProbe) {
+                if ([string]::IsNullOrWhiteSpace($RegionReferenceHash)) {
+                    throw '-RegionHashProbe requires -RegionReferenceHash from a reference full-ring run.'
+                }
+                $args += @(
+                    '-regionhashprobe',
+                    "-regionworkers=$RegionWorkers",
+                    "-regionreferencehash=$RegionReferenceHash"
+                )
+            }
             $commandletLedger = Invoke-UnrealLaunch 'region-eval-commandlet' $args `
                 $regionLog (Join-Path $RunRoot 'Logs\region-eval.stdout.log') `
                 (Join-Path $RunRoot 'Logs\region-eval.stderr.log')