wip(assembler): round S4 -- continuous far ceiling at the strate's upper boundary

S3's far cap sat up to 8.2 m above the near roof and read as floating pieces. The far render cap now projects onto the owning strate's upper boundary (density unchanged), on a global XY lattice, LOD4 16-voxel grid + LOD5-8 128-voxel. Cap agreement 0.05 cm (100 cm control detected), 2520/2520 upward rays hit roof on the owner walk. Far recipe v2; LOD0-3 hashes equal S2/S3. Tile p95 flat; cold clipmap +4.4%. Far-cliff fluting left open (coarse MC step). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ
2026-10-19 00:41:13 +02:00
1 parent d0f97bf79a
commit 9d3c50ca95
@@ -1395,6 +1395,46 @@ measure eight warmed keys per LOD and compare the shared LOD7/8 surface lattice
 density roots, including a 100 cm datum-offset negative control. See
 `Standalone/Research/WorldAssemblerM3/Round7/REPORT.md` for results and the visual evidence limits.

+### 8.25 Continuous planar ceiling — World Assembler S4 / M3 Round 8
+
+  The cap remains a family declaration in `WorldAssemblyPlanV1::strates` and is evaluated by the shared
+  Core heightfield path. `Heightfield2D::farSurfaceCapHeightSubvoxels()` clips only the rendered far
+  surface to `(topChunkZ + 1) * 32` voxels, the owning strate's upper boundary; it leaves
+  `Heightfield2D::point()` and its density values unchanged. `capHeightBounds()` reports conservative
+  bounds for that clipped surface. Evaluator v5 opts into this render-surface contract; older serialized
+  evaluators keep their recorded cap behavior. The clip joins the exact near density root at the owning
+  boundary without changing LOD0–3 density hashes. Future families with planar roofs must declare their
+  cap height and bounds through the family plan/provider contract; the shared tile generator consumes
+  that declaration. FloatingIslands declares no planar roof, so open sky above a surface island is the
+  expected view.
+
+For each requested far SurfaceWorld XY column at LOD4–8, desired-tile selection adds cap-height
+  bands only when they do not overlap an existing or already accepted 3D clipmap tile. The original
+  clipmap remains a non-overlapping partition. Cap samples use a global XY lattice, are clipped to the
+  owned strate boundary, tile Z bounds and `cap >= ground`, and share edges across tiles. LOD4 uses a 16-voxel cap step;
+LOD5–8 use 128 voxels. Core-off stays on its legacy path, and edits continue through the authoritative
+edited field. Runtime material sections are explicitly created/updated from their ground/cap index
+ranges so a cap-only far tile cannot rely on an auto-created section being present.
+
+The far recipe version is 2. It salts mesh, payload and topology hashes for LOD4–8; density hashes
+and LOD0–LOD3 identities do not change. The owner audit counts requested cap bands and emitted
+positive-area bands, compares 128 shared cap points with the near density root at 2 cm tolerance,
+checks a 100 cm datum-offset negative control, and traces upward rays from route and camera points
+against emitted triangles. Round 8 records these counters, the matched captures, warmed BuildHost
+timings, clipmap overlap validation and remaining failures in
+`Standalone/Research/WorldAssemblerM3/Round8/REPORT.md`.
+
+  The Round 8 owner walk audit emitted every requested cap band at LOD4–8 (385/385), agreed with 128
+  near roots to 0.0504 cm (2 cm gate), detected a 100 cm offset control, and hit the cap on all 2,520
+  upward rays from 35 walk/camera points. No route ray missed the cap or clipmap boundary.
+
+  The far-cliff fluting is coarse marching-cubes geometry on steep faces: with 16 coarse cells per tile,
+LOD7 samples every 256 voxels (64 m at 25 cm) and LOD8 every 512 voxels (128 m). The native ground
+replacement removes only upward-facing coarse faces; near-vertical faces remain on that lattice.
+LOD7/8 shell repair is skipped for certified SurfaceWorld tiles, the renderer does not cull
+backfaces, and the strips predate S4 in S2/S3. Refining all steep faces would multiply far mesh work;
+S4 leaves that cost/quality tradeoff open.
+
 ## 9. Multiplayer model (listen-server first, dedicated-friendly)

 > **Status: transport is DESIGN ONLY — nothing is networked in-tree yet** (no `Replicated`/`HasAuthority`/RPCs; a
@@ -979,6 +979,19 @@ time, repair field calls, skipped repairs and replaced triangles. `farHorizonVer
 mesh/payload/topology hashes only. The BuildHost commandlet owns warmed eight-key timings and the
 exact-density-root LOD7/8 agreement audit with its datum-offset negative control.

+  World Assembler S4 repairs the planar cap datum and far tile selection. `Heightfield2D::farSurfaceCapHeightSubvoxels`
+  clips the rendered cap to `(topChunkZ + 1) * 32` voxels while preserving `Heightfield2D::point` density;
+  `capHeightBounds` provides the matching conservative bands. `World::desiredTiles` adds only non-overlapping
+  cap-height keys at LOD4–8, and `RefineFarNativeCap` emits the globally aligned cap surface (16 voxels at
+  LOD4, 128 at LOD5–8). Evaluator v5 opts into this render-surface contract; older serialized evaluator
+  versions retain their cap behavior. Far recipe v2 salts mesh/payload/topology from LOD4 upward. The
+  standalone viewer audit measures cap-band census, near-root agreement and upward-ray coverage; the editor
+  BuildHost check measures the staged owner actor and W1/W8/W16. `VoxelWorld::ApplyMeshToTile` uses explicit
+  section ranges for ground and cap. Likely compile spots are the Core public/internal heightfield API and
+`VoxelForgeCore.cpp`, `VoxelWorld.cpp`, the editor commandlet, and the standalone viewer. See
+ARCHITECTURE §8.25 and
+[`Standalone/Research/WorldAssemblerM3/Round8/REPORT.md`](Standalone/Research/WorldAssemblerM3/Round8/REPORT.md).
+
 ## 4. The density pipeline (most-edited hot path)

 ### 4.1 `GetDensityWithParams` (TunnelNetwork) — VoxelGenerator.cpp:3749
@@ -24,6 +24,7 @@
 #include "VoxelClipmapDesiredTiles.h"
 #include "VoxelCollisionDesiredTiles.h"
 #include "VoxelPreEditDensityCache.h"
+#include "RealtimeMeshLibrary.h"
 // IWYU (FPSemantics = Precise ⇒ plus de PCH partagé) : GetPlayerPosition déréférence le pawn, donc
 // APawn doit être COMPLET — `Casts.h` n'en donne qu'une déclaration avant. APlayerController n'est
 // complet que par transitivité : on l'inclut explicitement.
@@ -12471,21 +12472,30 @@ bool AVoxelWorld::ApplyMeshToTile(FChunkResult& Result)
    // (default config already maps material slot = polygroup index); only config sections that
    // exist — the bHas* flags come from the worker. Collision at level 0 only (T1.c), both groups.
    const uint64 CollisionConfigStartCycles = bProfileApply ? FPlatformTime::Cycles64() : 0;
+    const int32 NumIndices = Result.NumTriangles * 3;
+    const int32 FirstCapIndex = FMath::Clamp(
+        NumIndices - Result.NumCeilingTriangles * 3, 0, NumIndices);
    if (bHasGroundTris)
    {
        FRealtimeMeshSectionConfig GroundConfig(0);
        GroundConfig.bCastsShadow = bCastShadow;
-        RTMesh->UpdateSectionConfig(
+        const FRealtimeMeshStreamRange GroundRange =
+            URealtimeMeshBlueprintFunctionLibrary::MakeStreamRange(
+                0, Result.NumVertices, 0, FirstCapIndex);
+        RTMesh->CreateSection(
            FRealtimeMeshSectionKey::CreateForPolyGroup(GroupKey, 0),
-            GroundConfig, /*bShouldCreateCollision*/ bWantsCollision);
+            GroundConfig, GroundRange, /*bShouldCreateCollision*/ bWantsCollision);
    }
    if (bHasCeilingTris)
    {
        FRealtimeMeshSectionConfig CapConfig(1);
        CapConfig.bCastsShadow = false;                      // the cap never casts (see above)
-        RTMesh->UpdateSectionConfig(
+        const FRealtimeMeshStreamRange CapRange =
+            URealtimeMeshBlueprintFunctionLibrary::MakeStreamRange(
+                0, Result.NumVertices, FirstCapIndex, NumIndices);
+        RTMesh->CreateSection(
            FRealtimeMeshSectionKey::CreateForPolyGroup(GroupKey, 1),
-            CapConfig, /*bShouldCreateCollision*/ bWantsCollision);
+            CapConfig, CapRange, /*bShouldCreateCollision*/ bWantsCollision);
    }
    const double CollisionConfigSeconds = bProfileApply
        ? FPlatformTime::ToSeconds64(FPlatformTime::Cycles64() - CollisionConfigStartCycles)
@@ -15221,7 +15221,8 @@ bool RunCoreFarHorizonAgreementAudit(VoxelForgeCore::World& World,
                    if(Other==Ground8.ByXY.end())continue;
                    const auto Column=Field.point(Pair.first.first,Pair.first.second,0);
                    const std::int64_t Ground=Column.groundHeightSubvoxels;
-                    const std::int64_t Cap=Column.capHeightSubvoxels;
+                    const std::int64_t Cap=Field.farSurfaceCapHeightSubvoxels(
+                        Pair.first.first,Pair.first.second);
                    if(Ground>=Cap)continue;
                    const double GroundVoxel=static_cast<double>(Ground)/SubvoxelsPerVoxel;
                    if(GroundVoxel<Bounds7[2]||GroundVoxel>Bounds7[5]
@@ -15263,7 +15264,8 @@ bool RunCoreFarHorizonAgreementAudit(VoxelForgeCore::World& World,
            const std::int64_t YSub=static_cast<std::int64_t>(std::llround(
                static_cast<double>(RouteYSub)/GridPeriod))*GridPeriod;
            const auto WalkColumn=Field.point(XSub,YSub,0);
-            if(WalkColumn.groundHeightSubvoxels>=WalkColumn.capHeightSubvoxels)continue;
+            const std::int64_t WalkCap=Field.farSurfaceCapHeightSubvoxels(XSub,YSub);
+            if(WalkColumn.groundHeightSubvoxels>=WalkCap)continue;
            const std::int64_t XVoxel=XSub/SubvoxelsPerVoxel,YVoxel=YSub/SubvoxelsPerVoxel;
            const std::int64_t WalkGroundVoxel=WalkColumn.groundHeightSubvoxels/SubvoxelsPerVoxel;
            const auto MakeKey=[](std::int64_t X,std::int64_t Y,std::int64_t Z,std::int64_t Extent,int32 LOD)
@@ -15293,7 +15295,8 @@ bool RunCoreFarHorizonAgreementAudit(VoxelForgeCore::World& World,
                if(Other==Ground8.ByXY.end())continue;
                const auto Column=Field.point(Pair.first.first,Pair.first.second,0);
                const std::int64_t Ground=Column.groundHeightSubvoxels;
-                if(Ground>=Column.capHeightSubvoxels)continue;
+                if(Ground>=Field.farSurfaceCapHeightSubvoxels(
+                    Pair.first.first,Pair.first.second))continue;
                const auto Bounds7=TileBounds(Key7),Bounds8=TileBounds(Key8);
                const double GroundVoxel=static_cast<double>(Ground)/SubvoxelsPerVoxel;
                if(GroundVoxel<Bounds7[2]||GroundVoxel>Bounds7[5]
@@ -15373,6 +15376,554 @@ bool RunCoreFarHorizonAgreementAudit(VoxelForgeCore::World& World,
    return true;
 }

+bool RunCoreFarCapTileCensus(VoxelForgeCore::World& World,
+    const VoxelForgeCore::WorldAssemblyManifest& Assembly,FString& OutError)
+{
+    OutError.Reset();
+    constexpr std::int64_t SubvoxelsPerVoxel=VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+    constexpr std::int64_t ProfileGridStep=128;
+    using FTileId=std::array<std::int32_t,4>;
+    using FXYLod=std::array<std::int32_t,3>;
+    const auto IdFor=[](const VoxelForgeCore::TileKey& Key)
+    {return FTileId{Key.coordinate.x,Key.coordinate.y,Key.coordinate.z,Key.lod};};
+    const auto FloorDiv64=[](std::int64_t Value,std::int64_t Divisor)
+    {
+        const std::int64_t Quotient=Value/Divisor, Remainder=Value%Divisor;
+        return Quotient-((Remainder!=0&&Remainder<0)?1:0);
+    };
+
+    const VoxelForgeCore::WorldAssemblyStratumPlanV1* Plan=nullptr;
+    for(const auto& Candidate:Assembly.plan.strates)
+        if(!Candidate.route.empty()) {Plan=&Candidate;break;}
+    if(Plan==nullptr)
+    {OutError=TEXT("Far-cap census has no SurfaceWorld walk route.");return false;}
+    const VoxelForgeCore::Heightfield2D Field(Assembly.recipe,*Plan);
+    if(!Field.isValid())
+    {OutError=TEXT("Far-cap census received an invalid SurfaceWorld heightfield.");return false;}
+
+    const auto& WalkStart=Plan->route.front();
+    const VoxelForgeCore::Vec3d Camera{
+        static_cast<double>(WalkStart.positionSubvoxels[0])/SubvoxelsPerVoxel,
+        static_cast<double>(WalkStart.positionSubvoxels[1])/SubvoxelsPerVoxel,
+        static_cast<double>(WalkStart.positionSubvoxels[2])/SubvoxelsPerVoxel};
+    const std::vector<VoxelForgeCore::TileKey> WalkKeys=World.desiredTiles(Camera);
+    std::set<FTileId> Desired;
+    std::set<FXYLod> FarXYTiles;
+    double ClipMaxZ=-std::numeric_limits<double>::infinity();
+    for(const auto& Key:WalkKeys)
+    {
+        Desired.insert(IdFor(Key));
+        const double Extent=static_cast<double>(32<<Key.lod);
+        ClipMaxZ=std::max(ClipMaxZ,(static_cast<double>(Key.coordinate.z)+1.0)*Extent);
+        if(Key.lod>=5&&Key.lod<=8)
+            FarXYTiles.insert({Key.coordinate.x,Key.coordinate.y,Key.lod});
+    }
+    std::set<FTileId> CapBands;
+    std::uint64_t ProfileGridSamples=0, ProfileSamplesWithoutRoof=0;
+    std::set<FXYLod> FarXYTilesWithoutRoof;
+    for(const FXYLod& XY:FarXYTiles)
+    {
+        const std::int32_t Lod=XY[2];
+        const std::int64_t Extent=static_cast<std::int64_t>(32)<<Lod;
+        const std::int64_t OriginX=static_cast<std::int64_t>(XY[0])*Extent;
+        const std::int64_t OriginY=static_cast<std::int64_t>(XY[1])*Extent;
+        for(std::int64_t Y=0;Y<=Extent;Y+=ProfileGridStep)
+        for(std::int64_t X=0;X<=Extent;X+=ProfileGridStep)
+        {
+            ++ProfileGridSamples;
+            const auto Column=Field.point((OriginX+X)*SubvoxelsPerVoxel,
+                (OriginY+Y)*SubvoxelsPerVoxel,0);
+            const std::int64_t FarCap=Field.farSurfaceCapHeightSubvoxels(
+                (OriginX+X)*SubvoxelsPerVoxel,(OriginY+Y)*SubvoxelsPerVoxel);
+            if(FarCap<=Column.groundHeightSubvoxels)
+            {
+                ++ProfileSamplesWithoutRoof;
+                FarXYTilesWithoutRoof.insert(XY);
+                continue;
+            }
+            const std::int64_t Band=FloorDiv64(FarCap,
+                Extent*SubvoxelsPerVoxel);
+            if(Band>=MIN_int32&&Band<=MAX_int32)
+                CapBands.insert({XY[0],XY[1],static_cast<std::int32_t>(Band),Lod});
+            if(FarCap%(Extent*SubvoxelsPerVoxel)==0
+                &&Band>MIN_int32)
+                CapBands.insert({XY[0],XY[1],static_cast<std::int32_t>(Band-1),Lod});
+        }
+    }
+
+    std::uint64_t RequestedCapBands=0, EmittedCapBands=0, RequestedWithoutTriangles=0;
+    std::uint64_t CulledCapBands=0;
+    std::map<std::int32_t,std::array<std::uint64_t,4>> ByLod;
+    VoxelForgeCore::TileGenerationOptions Options;
+    std::string CoreError;
+    struct FCapAgreementSample
+    { std::int64_t XSub=0,YSub=0;double FarZVoxel=0.0; };
+    using FCapXYKey=std::pair<std::int64_t,std::int64_t>;
+    std::set<FCapXYKey> CapAgreementSeen;
+    std::vector<FCapAgreementSample> CapAgreementSamples;
+    CapAgreementSamples.reserve(128);
+    const double VoxelSizeCm=static_cast<double>(World.configuration().voxelSizeMicrons)/10000.0;
+    constexpr std::int64_t CapGridPeriod=128*SubvoxelsPerVoxel;
+    for(const FTileId& Id:CapBands)
+    {
+        const std::int32_t Lod=Id[3];
+        auto& Counts=ByLod[Lod];
+        ++Counts[0];
+        if(Desired.find(Id)==Desired.end())
+        {
+            ++CulledCapBands;++Counts[1];continue;
+        }
+        ++RequestedCapBands;
+        VoxelForgeCore::TileKey Key{{Id[0],Id[1],Id[2]},Lod};
+        const auto Mesh=World.generateTile(Key,Options,CoreError);
+        if(!Mesh)
+        {
+            OutError=FString::Printf(TEXT("Far-cap census tile generation failed at (%d,%d,%d) LOD%d: %s"),
+                Id[0],Id[1],Id[2],Lod,UTF8_TO_TCHAR(CoreError.c_str()));
+            return false;
+        }
+        if(Mesh->diagnostics.horizonCapTriangles>0)
+        {
+            ++EmittedCapBands;++Counts[2];
+            const std::size_t CapIndexStart=Mesh->indices.size()
+                -static_cast<std::size_t>(Mesh->diagnostics.horizonCapTriangles)*3u;
+            for(std::size_t Index=CapIndexStart;Index<Mesh->indices.size()
+                &&CapAgreementSamples.size()<128;++Index)
+            {
+                const std::uint32_t VertexIndex=Mesh->indices[Index];
+                if(VertexIndex>=Mesh->vertices.size())continue;
+                const auto& Vertex=Mesh->vertices[VertexIndex];
+                if(Vertex.normal.z>=-0.35)continue;
+                const std::int64_t XSub=static_cast<std::int64_t>(std::llround(
+                    Vertex.position.x/VoxelSizeCm*SubvoxelsPerVoxel));
+                const std::int64_t YSub=static_cast<std::int64_t>(std::llround(
+                    Vertex.position.y/VoxelSizeCm*SubvoxelsPerVoxel));
+                if(XSub%CapGridPeriod!=0||YSub%CapGridPeriod!=0)continue;
+                if(!CapAgreementSeen.insert({XSub,YSub}).second)continue;
+                CapAgreementSamples.push_back({XSub,YSub,
+                    Vertex.position.z/VoxelSizeCm});
+            }
+        }
+        else
+        {++RequestedWithoutTriangles;++Counts[3];}
+    }
+
+    constexpr double CapAgreementToleranceCm=2.0;
+    constexpr double CapNegativeDatumOffsetCm=100.0;
+    const auto FindNearCapRoot=[&](std::int64_t XSub,std::int64_t YSub,
+        double ProfileCapVoxel,double& OutRootVoxel)
+    {
+        const double X=static_cast<double>(XSub)/SubvoxelsPerVoxel;
+        const double Y=static_cast<double>(YSub)/SubvoxelsPerVoxel;
+        for(double Radius=4.0;Radius<=4096.0;Radius*=2.0)
+        {
+            double Lo=ProfileCapVoxel-Radius,Hi=ProfileCapVoxel+Radius;
+            if(!(World.densityAt({X,Y,Lo})>=0.0f&&World.densityAt({X,Y,Hi})<0.0f))continue;
+            for(int Iteration=0;Iteration<16;++Iteration)
+            {
+                const double Mid=(Lo+Hi)*0.5;
+                if(World.densityAt({X,Y,Mid})>=0.0f)Lo=Mid;else Hi=Mid;
+            }
+            OutRootVoxel=(Lo+Hi)*0.5;
+            return true;
+        }
+        return false;
+    };
+    double MaximumCapAgreementErrorCm=0.0,MaximumCapNegativeControlErrorCm=0.0;
+    std::uint64_t CapAgreementCompared=0;
+    for(const FCapAgreementSample& Sample:CapAgreementSamples)
+    {
+        const auto Column=Field.point(Sample.XSub,Sample.YSub,0);
+        const std::int64_t FarCap=Field.farSurfaceCapHeightSubvoxels(
+            Sample.XSub,Sample.YSub);
+        if(FarCap<=Column.groundHeightSubvoxels)continue;
+        double NearRootVoxel=0.0;
+        if(!FindNearCapRoot(Sample.XSub,Sample.YSub,
+                static_cast<double>(FarCap)/SubvoxelsPerVoxel,NearRootVoxel))continue;
+        const double FarCapCm=Sample.FarZVoxel*VoxelSizeCm;
+        const double NearCapCm=NearRootVoxel*VoxelSizeCm;
+        MaximumCapAgreementErrorCm=std::max(MaximumCapAgreementErrorCm,
+            std::abs(FarCapCm-NearCapCm));
+        MaximumCapNegativeControlErrorCm=std::max(MaximumCapNegativeControlErrorCm,
+            std::abs(FarCapCm+CapNegativeDatumOffsetCm-NearCapCm));
+        ++CapAgreementCompared;
+    }
+    const bool bCapNegativeControlDetected=CapAgreementCompared>0
+        &&MaximumCapNegativeControlErrorCm>CapAgreementToleranceCm;
+    UE_LOG(LogTemp,Display,
+        TEXT("[VoxelForgeFarCapAgreement] status=%s shared_points=%llu max_far_near_cm=%.4f tolerance_cm=%.2f near_source=exact_density_root negative_control=100cm_datum_offset max_error_cm=%.4f detected=%d"),
+        CapAgreementCompared>=32&&MaximumCapAgreementErrorCm<=CapAgreementToleranceCm
+            &&bCapNegativeControlDetected?TEXT("PASS"):TEXT("FAIL"),
+        static_cast<unsigned long long>(CapAgreementCompared),MaximumCapAgreementErrorCm,
+        CapAgreementToleranceCm,MaximumCapNegativeControlErrorCm,bCapNegativeControlDetected?1:0);
+    if(CapAgreementCompared<32||MaximumCapAgreementErrorCm>CapAgreementToleranceCm
+        ||!bCapNegativeControlDetected)
+    {
+        OutError=FString::Printf(TEXT("Far-cap agreement failed: points=%llu max_error_cm=%.4f tolerance_cm=%.2f negative_control_cm=%.4f detected=%d."),
+            static_cast<unsigned long long>(CapAgreementCompared),MaximumCapAgreementErrorCm,
+            CapAgreementToleranceCm,MaximumCapNegativeControlErrorCm,bCapNegativeControlDetected?1:0);
+        return false;
+    }
+
+    // Les rayons couvrent l'hemisphere superieur depuis chaque point de marche.
+    // Cast into the upper view hemisphere from every authored walk point.
+    constexpr double Pi=3.14159265358979323846;
+    constexpr std::array<double,8> AzimuthDegrees={0.0,45.0,90.0,135.0,180.0,225.0,270.0,315.0};
+    constexpr std::array<double,6> ElevationDegrees={15.0,30.0,45.0,60.0,75.0,90.0};
+    constexpr double RayStepVoxels=128.0;
+    double ClipMinX=std::numeric_limits<double>::infinity();
+    double ClipMinY=std::numeric_limits<double>::infinity();
+    double ClipMaxX=-std::numeric_limits<double>::infinity();
+    double ClipMaxY=-std::numeric_limits<double>::infinity();
+    for(const FXYLod& XY:FarXYTiles)
+    {
+        const double Extent=static_cast<double>(32<<XY[2]);
+        ClipMinX=std::min(ClipMinX,static_cast<double>(XY[0])*Extent);
+        ClipMinY=std::min(ClipMinY,static_cast<double>(XY[1])*Extent);
+        ClipMaxX=std::max(ClipMaxX,(static_cast<double>(XY[0])+1.0)*Extent);
+        ClipMaxY=std::max(ClipMaxY,(static_cast<double>(XY[1])+1.0)*Extent);
+    }
+    enum class ECapRayTileResult : std::uint8_t
+    { EmittedHit, CulledByClipmap, RequestedWithoutTriangles, EmittedWithoutHit };
+    struct FCapRayTileGeometry
+    {
+        std::vector<std::array<VoxelForgeCore::Vec3d,3>> Triangles;
+    };
+    std::uint64_t RayCount=0, RayHits=0, RayMissedClipEdge=0;
+    std::uint64_t RayMissedNoRoof=0, RayMissedCulledByClipmap=0;
+    std::uint64_t RayMissedRequestedWithoutTriangles=0, RayMissedEmittedWithoutHit=0;
+    std::uint64_t RayStartedAboveCap=0;
+    std::uint64_t RayProfileCrossings=0,RayProfileRoofCrossings=0,RayProfileRoofWithoutMeshHit=0;
+    std::array<std::array<std::uint64_t,6>,6> RayResultsByElevation{};
+    std::vector<double> RayHitDistancesMeters;
+    RayHitDistancesMeters.reserve(Plan->route.size()*AzimuthDegrees.size()*ElevationDegrees.size());
+    std::map<FTileId,FCapRayTileGeometry> RayTileGeometryCache;
+    const auto GetCapRayTileGeometry=[&](const FTileId& Id)->const FCapRayTileGeometry*
+    {
+        auto Found=RayTileGeometryCache.find(Id);
+        if(Found!=RayTileGeometryCache.end())return &Found->second;
+        const VoxelForgeCore::TileKey Key{{Id[0],Id[1],Id[2]},Id[3]};
+        const auto Mesh=World.generateTile(Key,Options,CoreError);
+        if(!Mesh)
+        {
+            OutError=FString::Printf(TEXT("Far-cap ray tile generation failed at (%d,%d,%d) LOD%d: %s"),
+                Id[0],Id[1],Id[2],Id[3],UTF8_TO_TCHAR(CoreError.c_str()));
+            return nullptr;
+        }
+        FCapRayTileGeometry Geometry;
+        Geometry.Triangles.reserve(Mesh->groups.ceilingTriangleCount);
+        for(std::size_t Index=0;Index+2<Mesh->indices.size();Index+=3)
+        {
+            const std::uint32_t IA=Mesh->indices[Index],IB=Mesh->indices[Index+1],IC=Mesh->indices[Index+2];
+            if(IA>=Mesh->vertices.size()||IB>=Mesh->vertices.size()||IC>=Mesh->vertices.size())continue;
+            const double AverageNormalZ=(Mesh->vertices[IA].normal.z+Mesh->vertices[IB].normal.z
+                +Mesh->vertices[IC].normal.z)/3.0;
+            // Native marching-cubes roofs and refined far caps both face out of the solid
+            // toward decreasing Z density. Include those ceiling faces at LOD0-8.
+            // Les plafonds MC natifs et les caps lointains pointent hors du solide, vers -Z.
+            if(AverageNormalZ>=-0.05)continue;
+            Geometry.Triangles.push_back({
+                VoxelForgeCore::Vec3d{Mesh->vertices[IA].position.x/VoxelSizeCm,
+                    Mesh->vertices[IA].position.y/VoxelSizeCm,Mesh->vertices[IA].position.z/VoxelSizeCm},
+                VoxelForgeCore::Vec3d{Mesh->vertices[IB].position.x/VoxelSizeCm,
+                    Mesh->vertices[IB].position.y/VoxelSizeCm,Mesh->vertices[IB].position.z/VoxelSizeCm},
+                VoxelForgeCore::Vec3d{Mesh->vertices[IC].position.x/VoxelSizeCm,
+                    Mesh->vertices[IC].position.y/VoxelSizeCm,Mesh->vertices[IC].position.z/VoxelSizeCm}});
+        }
+        return &RayTileGeometryCache.emplace(Id,std::move(Geometry)).first->second;
+    };
+    const auto Dot3=[](const VoxelForgeCore::Vec3d& A,const VoxelForgeCore::Vec3d& B)
+    {return A.x*B.x+A.y*B.y+A.z*B.z;};
+    const auto Sub3=[](const VoxelForgeCore::Vec3d& A,const VoxelForgeCore::Vec3d& B)
+    {return VoxelForgeCore::Vec3d{A.x-B.x,A.y-B.y,A.z-B.z};};
+    const auto Cross3=[](const VoxelForgeCore::Vec3d& A,const VoxelForgeCore::Vec3d& B)
+    {return VoxelForgeCore::Vec3d{A.y*B.z-A.z*B.y,A.z*B.x-A.x*B.z,A.x*B.y-A.y*B.x};};
+    const auto RayTriangleDistance=[&](const VoxelForgeCore::Vec3d& Origin,
+        const VoxelForgeCore::Vec3d& Direction,const std::array<VoxelForgeCore::Vec3d,3>& Triangle,
+        double MinimumDistance,double MaximumDistance,double& OutDistance)
+    {
+        const auto Edge1=Sub3(Triangle[1],Triangle[0]);
+        const auto Edge2=Sub3(Triangle[2],Triangle[0]);
+        const auto P=Cross3(Direction,Edge2);
+        const double Determinant=Dot3(Edge1,P);
+        if(std::abs(Determinant)<1.0e-12)return false;
+        const double Inverse=1.0/Determinant;
+        const auto T=Sub3(Origin,Triangle[0]);
+        const double U=Dot3(T,P)*Inverse;
+        if(U< -1.0e-8||U>1.0+1.0e-8)return false;
+        const auto Q=Cross3(T,Edge1);
+        const double V=Dot3(Direction,Q)*Inverse;
+        if(V< -1.0e-8||U+V>1.0+1.0e-8)return false;
+        const double Distance=Dot3(Edge2,Q)*Inverse;
+        if(Distance<MinimumDistance-1.0e-6||Distance>MaximumDistance+1.0e-6)return false;
+        OutDistance=Distance;
+        return true;
+    };
+    const auto TraceEmittedCapRay=[&](const VoxelForgeCore::Vec3d& Origin,
+        const VoxelForgeCore::Vec3d& Direction,double MaximumDistance,double& OutHitDistance)
+    {
+        bool bFoundRequestedKey=false,bFoundEmptyRequestedKey=false,bFoundGeometryWithoutHit=false;
+        bool bFoundHit=false;
+        for(const FTileId& Id:Desired)
+        {
+            const double Extent=static_cast<double>(32<<Id[3]);
+            const std::array<double,3> BoundsMin={static_cast<double>(Id[0])*Extent,
+                static_cast<double>(Id[1])*Extent,static_cast<double>(Id[2])*Extent};
+            const std::array<double,3> BoundsMax={BoundsMin[0]+Extent,BoundsMin[1]+Extent,
+                BoundsMin[2]+Extent};
+            double TileEnter=0.0,TileExit=MaximumDistance;
+            bool bIntersects=true;
+            for(std::size_t Axis=0;Axis<3;++Axis)
+            {
+                const double RayOrigin=Axis==0?Origin.x:(Axis==1?Origin.y:Origin.z);
+                const double RayDirection=Axis==0?Direction.x:(Axis==1?Direction.y:Direction.z);
+                if(std::abs(RayDirection)<1.0e-12)
+                {
+                    if(RayOrigin<BoundsMin[Axis]||RayOrigin>BoundsMax[Axis])
+                    {bIntersects=false;break;}
+                    continue;
+                }
+                double Near=(BoundsMin[Axis]-RayOrigin)/RayDirection;
+                double Far=(BoundsMax[Axis]-RayOrigin)/RayDirection;
+                if(Near>Far)std::swap(Near,Far);
+                TileEnter=std::max(TileEnter,Near);
+                TileExit=std::min(TileExit,Far);
+                if(TileEnter>TileExit){bIntersects=false;break;}
+            }
+            if(!bIntersects||TileExit<0.0||TileEnter>MaximumDistance)continue;
+            bFoundRequestedKey=true;
+            const FCapRayTileGeometry* Geometry=GetCapRayTileGeometry(Id);
+            if(Geometry==nullptr)continue;
+            if(Geometry->Triangles.empty())
+            {bFoundEmptyRequestedKey=true;continue;}
+            bFoundGeometryWithoutHit=true;
+            for(const auto& Triangle:Geometry->Triangles)
+            {
+                double HitDistance=0.0;
+                if(!RayTriangleDistance(Origin,Direction,Triangle,
+                        std::max(0.0,TileEnter),std::min(MaximumDistance,TileExit),HitDistance))continue;
+                if(!bFoundHit||HitDistance<OutHitDistance)OutHitDistance=HitDistance;
+                bFoundHit=true;
+            }
+            if(!OutError.IsEmpty())return ECapRayTileResult::RequestedWithoutTriangles;
+        }
+        if(bFoundHit)return ECapRayTileResult::EmittedHit;
+        if(bFoundRequestedKey&&bFoundGeometryWithoutHit)return ECapRayTileResult::EmittedWithoutHit;
+        if(bFoundRequestedKey&&bFoundEmptyRequestedKey)return ECapRayTileResult::RequestedWithoutTriangles;
+        return ECapRayTileResult::CulledByClipmap;
+    };
+    for(std::size_t RouteIndex=0;RouteIndex<Plan->route.size();++RouteIndex)
+    {
+        const auto& RoutePoint=Plan->route[RouteIndex];
+        const double StartX=static_cast<double>(RoutePoint.positionSubvoxels[0])/SubvoxelsPerVoxel;
+        const double StartY=static_cast<double>(RoutePoint.positionSubvoxels[1])/SubvoxelsPerVoxel;
+        const double StartZ=static_cast<double>(RoutePoint.positionSubvoxels[2])/SubvoxelsPerVoxel;
+        const auto StartColumn=Field.point(RoutePoint.positionSubvoxels[0],
+            RoutePoint.positionSubvoxels[1],0);
+        const double StartCap=static_cast<double>(Field.farSurfaceCapHeightSubvoxels(
+            RoutePoint.positionSubvoxels[0],RoutePoint.positionSubvoxels[1]))/SubvoxelsPerVoxel;
+        for(const double Elevation:ElevationDegrees)
+        for(const double Azimuth:AzimuthDegrees)
+        {
+            ++RayCount;
+            const std::size_t ElevationIndex=static_cast<std::size_t>(
+                std::find(ElevationDegrees.begin(),ElevationDegrees.end(),Elevation)
+                    -ElevationDegrees.begin());
+            if(!(StartCap>StartZ))
+            {++RayStartedAboveCap;++RayMissedNoRoof;++RayResultsByElevation[ElevationIndex][4];continue;}
+            const double ElevationRadians=Elevation*Pi/180.0;
+            const double AzimuthRadians=Azimuth*Pi/180.0;
+            const double DX=std::cos(ElevationRadians)*std::cos(AzimuthRadians);
+            const double DY=std::cos(ElevationRadians)*std::sin(AzimuthRadians);
+            const double DZ=std::sin(ElevationRadians);
+            double EdgeDistance=std::numeric_limits<double>::infinity();
+            if(DX>1.0e-9)EdgeDistance=std::min(EdgeDistance,(ClipMaxX-StartX)/DX);
+            else if(DX< -1.0e-9)EdgeDistance=std::min(EdgeDistance,(ClipMinX-StartX)/DX);
+            if(DY>1.0e-9)EdgeDistance=std::min(EdgeDistance,(ClipMaxY-StartY)/DY);
+            else if(DY< -1.0e-9)EdgeDistance=std::min(EdgeDistance,(ClipMinY-StartY)/DY);
+            if(DZ>1.0e-9)
+                EdgeDistance=std::min(EdgeDistance,(ClipMaxZ-StartZ)/DZ);
+            if(!std::isfinite(EdgeDistance)||EdgeDistance<=0.0)
+            {++RayMissedClipEdge;++RayResultsByElevation[ElevationIndex][5];continue;}
+            bool bProfileCrossing=false,bProfileRoofAtCrossing=false;
+            double ProfileHitDistance=std::numeric_limits<double>::infinity();
+            double ProfileHitX=0.0,ProfileHitY=0.0,ProfileHitZ=0.0;
+            std::int64_t ProfileHitCapSubvoxels=0;
+            double PreviousDistance=0.0,PreviousDelta=StartZ-StartCap;
+            for(double Distance=std::min(RayStepVoxels,EdgeDistance);;)
+            {
+                const double X=StartX+DX*Distance,Y=StartY+DY*Distance;
+                const double Z=StartZ+DZ*Distance;
+                const std::int64_t CapSubvoxels=Field.farSurfaceCapHeightSubvoxels(
+                    static_cast<std::int64_t>(std::llround(X*SubvoxelsPerVoxel)),
+                    static_cast<std::int64_t>(std::llround(Y*SubvoxelsPerVoxel)));
+                const double Cap=static_cast<double>(CapSubvoxels)/SubvoxelsPerVoxel;
+                const double Delta=Z-Cap;
+                if(PreviousDelta<0.0&&Delta>=0.0)
+                {
+                    const double Fraction=-PreviousDelta/(Delta-PreviousDelta);
+                    ProfileHitDistance=PreviousDistance+(Distance-PreviousDistance)*Fraction;
+                    const double HitX=StartX+DX*ProfileHitDistance;
+                    const double HitY=StartY+DY*ProfileHitDistance;
+                    const auto HitColumn=Field.point(
+                        static_cast<std::int64_t>(std::llround(HitX*SubvoxelsPerVoxel)),
+                        static_cast<std::int64_t>(std::llround(HitY*SubvoxelsPerVoxel)),0);
+                    const std::int64_t HitCapSubvoxels=Field.farSurfaceCapHeightSubvoxels(
+                        static_cast<std::int64_t>(std::llround(HitX*SubvoxelsPerVoxel)),
+                        static_cast<std::int64_t>(std::llround(HitY*SubvoxelsPerVoxel)));
+                    bProfileCrossing=true;
+                    bProfileRoofAtCrossing=HitCapSubvoxels>HitColumn.groundHeightSubvoxels;
+                    ProfileHitX=HitX;ProfileHitY=HitY;
+                    ProfileHitZ=StartZ+DZ*ProfileHitDistance;
+                    ProfileHitCapSubvoxels=HitCapSubvoxels;
+                    ++RayProfileCrossings;
+                    if(bProfileRoofAtCrossing)++RayProfileRoofCrossings;
+                    break;
+                }
+                PreviousDistance=Distance;PreviousDelta=Delta;
+                if(Distance>=EdgeDistance)break;
+                Distance=std::min(Distance+RayStepVoxels,EdgeDistance);
+            }
+            const VoxelForgeCore::Vec3d RayOrigin{StartX,StartY,StartZ};
+            const VoxelForgeCore::Vec3d RayDirection{DX,DY,DZ};
+            double MeshHitDistance=std::numeric_limits<double>::infinity();
+            const ECapRayTileResult TileResult=TraceEmittedCapRay(
+                RayOrigin,RayDirection,EdgeDistance,MeshHitDistance);
+            if(!OutError.IsEmpty())return false;
+            switch(TileResult)
+            {
+                case ECapRayTileResult::EmittedHit:
+                    ++RayHits;++RayResultsByElevation[ElevationIndex][0];
+                    RayHitDistancesMeters.push_back(MeshHitDistance*VoxelSizeCm/100.0);break;
+                case ECapRayTileResult::CulledByClipmap:
+                    ++RayMissedCulledByClipmap;++RayResultsByElevation[ElevationIndex][1];break;
+                case ECapRayTileResult::RequestedWithoutTriangles:
+                    ++RayMissedRequestedWithoutTriangles;++RayResultsByElevation[ElevationIndex][2];break;
+                case ECapRayTileResult::EmittedWithoutHit:
+                {
+                    ++RayMissedEmittedWithoutHit;++RayResultsByElevation[ElevationIndex][3];
+                    if(bProfileCrossing&&bProfileRoofAtCrossing)++RayProfileRoofWithoutMeshHit;
+                    std::uint32_t FarRequestedMask=0,FarEmittedMask=0;
+                    std::uint32_t RootRequestedMask=0,RootEmittedMask=0;
+                    std::uint64_t RootDownwardTriangles=0;
+                    if(bProfileCrossing&&bProfileRoofAtCrossing)
+                    {
+                        for(std::int32_t Lod=0;Lod<=8;++Lod)
+                        {
+                            const std::int64_t Extent=static_cast<std::int64_t>(32)<<Lod;
+                            const std::int64_t TileX=FloorDiv64(static_cast<std::int64_t>(std::floor(ProfileHitX)),Extent);
+                            const std::int64_t TileY=FloorDiv64(static_cast<std::int64_t>(std::floor(ProfileHitY)),Extent);
+                            const std::int64_t TileZ=FloorDiv64(ProfileHitCapSubvoxels,Extent*SubvoxelsPerVoxel);
+                            const FTileId Id{static_cast<std::int32_t>(TileX),static_cast<std::int32_t>(TileY),
+                                static_cast<std::int32_t>(TileZ),Lod};
+                            if(Desired.find(Id)==Desired.end())continue;
+                            RootRequestedMask|=1u<<static_cast<std::uint32_t>(Lod);
+                            const FCapRayTileGeometry* Geometry=GetCapRayTileGeometry(Id);
+                            if(Geometry!=nullptr)
+                            {
+                                RootDownwardTriangles+=Geometry->Triangles.size();
+                                if(!Geometry->Triangles.empty())
+                                    RootEmittedMask|=1u<<static_cast<std::uint32_t>(Lod);
+                            }
+                            if(Lod>=5)
+                            {
+                                FarRequestedMask|=1u<<static_cast<std::uint32_t>(Lod-5);
+                                if(Geometry!=nullptr&&!Geometry->Triangles.empty())
+                                    FarEmittedMask|=1u<<static_cast<std::uint32_t>(Lod-5);
+                            }
+                        }
+                    }
+                    UE_LOG(LogTemp,Display,
+                        TEXT("[VoxelForgeFarCapRayMiss] route_point=%llu elevation_deg=%.0f azimuth_deg=%.0f profile_crossing=%d profile_roof=%d profile_distance_vox=%.1f clip_distance_vox=%.1f profile_hit_vox=(%.1f,%.1f,%.1f) root_lod_requested_mask=0x%X root_lod_emitted_mask=0x%X root_downward_triangles=%llu far_requested_mask=0x%X far_emitted_mask=0x%X"),
+                        static_cast<unsigned long long>(RouteIndex),Elevation,Azimuth,
+                        bProfileCrossing?1:0,bProfileRoofAtCrossing?1:0,
+                        ProfileHitDistance,EdgeDistance,ProfileHitX,ProfileHitY,ProfileHitZ,
+                        RootRequestedMask,RootEmittedMask,
+                        static_cast<unsigned long long>(RootDownwardTriangles),
+                        FarRequestedMask,FarEmittedMask);
+                    break;
+                }
+            }
+        }
+    }
+
+    const auto WalkColumn=Field.point(WalkStart.positionSubvoxels[0],
+        WalkStart.positionSubvoxels[1],0);
+    const std::int64_t WalkFarCap=Field.farSurfaceCapHeightSubvoxels(
+        WalkStart.positionSubvoxels[0],WalkStart.positionSubvoxels[1]);
+    std::size_t RayTriangleCount=0;
+    for(const auto& [Id,Geometry]:RayTileGeometryCache)
+    { (void)Id;RayTriangleCount+=Geometry.Triangles.size(); }
+    std::sort(RayHitDistancesMeters.begin(),RayHitDistancesMeters.end());
+    const double HitDistanceP50Meters=RayHitDistancesMeters.empty()?0.0:
+        RayHitDistancesMeters[(RayHitDistancesMeters.size()-1)*50/100];
+    const double HitDistanceP95Meters=RayHitDistancesMeters.empty()?0.0:
+        RayHitDistancesMeters[(RayHitDistancesMeters.size()-1)*95/100];
+    const double HitDistanceMaximumMeters=RayHitDistancesMeters.empty()?0.0:
+        RayHitDistancesMeters.back();
+    UE_LOG(LogTemp,Display,
+        TEXT("[VoxelForgeFarCapCensus] source=surface_route_front route_points=%llu walk_keys=%llu far_xy_tiles=%llu cap_bands=%llu requested=%llu emitted=%llu requested_without_triangles=%llu culled_by_clipmap=%llu grid_samples=%llu samples_without_roof=%llu xy_tiles_with_roof_gaps=%llu walk_z_vox=%.3f ground_z_vox=%.3f cap_z_vox=%.3f"),
+        static_cast<unsigned long long>(Plan->route.size()),
+        static_cast<unsigned long long>(WalkKeys.size()),
+        static_cast<unsigned long long>(FarXYTiles.size()),
+        static_cast<unsigned long long>(CapBands.size()),
+        static_cast<unsigned long long>(RequestedCapBands),
+        static_cast<unsigned long long>(EmittedCapBands),
+        static_cast<unsigned long long>(RequestedWithoutTriangles),
+        static_cast<unsigned long long>(CulledCapBands),
+        static_cast<unsigned long long>(ProfileGridSamples),
+        static_cast<unsigned long long>(ProfileSamplesWithoutRoof),
+        static_cast<unsigned long long>(FarXYTilesWithoutRoof.size()),
+        Camera.z,static_cast<double>(WalkColumn.groundHeightSubvoxels)/SubvoxelsPerVoxel,
+        static_cast<double>(WalkFarCap)/SubvoxelsPerVoxel);
+    const double CoveragePercent=RayCount>0?100.0*static_cast<double>(RayHits)/RayCount:0.0;
+    UE_LOG(LogTemp,Display,
+        TEXT("[VoxelForgeFarCapRayCoverage] rays=%llu mesh_hits=%llu coverage_pct=%.3f missed_clip_edge=%llu missed_no_roof=%llu missed_cap_key_culled=%llu missed_requested_without_triangles=%llu missed_emitted_without_mesh_hit=%llu start_above_cap=%llu profile_crossings=%llu profile_roof_crossings=%llu profile_roof_without_mesh_hit=%llu traced_tiles=%llu traced_downward_triangles=%llu first_hit_distance_m_p50=%.2f_p95=%.2f_max=%.2f elevations_deg=15,30,45,60,75,90 azimuths=8 ray_method=all_downward_emitted_triangles_with_tile_aabb clip_edge=desired_far_xy_bounds lods_checked=0-8"),
+        static_cast<unsigned long long>(RayCount),static_cast<unsigned long long>(RayHits),CoveragePercent,
+        static_cast<unsigned long long>(RayMissedClipEdge),
+        static_cast<unsigned long long>(RayMissedNoRoof),
+        static_cast<unsigned long long>(RayMissedCulledByClipmap),
+        static_cast<unsigned long long>(RayMissedRequestedWithoutTriangles),
+        static_cast<unsigned long long>(RayMissedEmittedWithoutHit),
+        static_cast<unsigned long long>(RayStartedAboveCap),
+        static_cast<unsigned long long>(RayProfileCrossings),
+        static_cast<unsigned long long>(RayProfileRoofCrossings),
+        static_cast<unsigned long long>(RayProfileRoofWithoutMeshHit),
+        static_cast<unsigned long long>(RayTileGeometryCache.size()),
+        static_cast<unsigned long long>(RayTriangleCount),HitDistanceP50Meters,
+        HitDistanceP95Meters,HitDistanceMaximumMeters);
+    for(std::size_t Index=0;Index<ElevationDegrees.size();++Index)
+        UE_LOG(LogTemp,Display,
+            TEXT("[VoxelForgeFarCapRayElevation] degrees=%.0f rays=%llu mesh_hits=%llu key_culled=%llu requested_empty=%llu emitted_without_mesh_hit=%llu no_roof_or_above=%llu missed_clip_edge=%llu"),
+            ElevationDegrees[Index],
+            static_cast<unsigned long long>(AzimuthDegrees.size()*Plan->route.size()),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][0]),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][1]),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][2]),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][3]),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][4]),
+            static_cast<unsigned long long>(RayResultsByElevation[Index][5]));
+    if(RayHits!=RayCount)
+    {
+        OutError=FString::Printf(TEXT("Far-cap ray coverage failed: rays=%llu mesh_hits=%llu clip_edge=%llu no_roof=%llu culled_keys=%llu requested_empty=%llu emitted_without_hit=%llu."),
+            static_cast<unsigned long long>(RayCount),static_cast<unsigned long long>(RayHits),
+            static_cast<unsigned long long>(RayMissedClipEdge),
+            static_cast<unsigned long long>(RayMissedNoRoof),
+            static_cast<unsigned long long>(RayMissedCulledByClipmap),
+            static_cast<unsigned long long>(RayMissedRequestedWithoutTriangles),
+            static_cast<unsigned long long>(RayMissedEmittedWithoutHit));
+        return false;
+    }
+    for(const auto& [Lod,Counts]:ByLod)
+        UE_LOG(LogTemp,Display,
+            TEXT("[VoxelForgeFarCapCensusLOD] lod=%d cap_bands=%llu culled=%llu emitted=%llu requested_without_triangles=%llu"),
+            Lod,static_cast<unsigned long long>(Counts[0]),
+            static_cast<unsigned long long>(Counts[1]),
+            static_cast<unsigned long long>(Counts[2]),
+            static_cast<unsigned long long>(Counts[3]));
+    return true;
+}
+
 // Paired engine timings include preparation and derived shells, with canonical output hashes.
 // Mesures moteur appariees : preparation et coques derivees incluses, avec hashes canoniques.
 bool RunCoreSharedFeatureCostAudit(VoxelForgeCore::World& World,
@@ -15441,8 +15992,12 @@ bool RunCoreSharedFeatureCostAudit(VoxelForgeCore::World& World,
            P95(ConnectorShellTimes),P95(ConnectorFieldCalls),P95(ShellTriangles),
            P95(GroundTriangles),P95(GroundRemoved),P95(CapTriangles));
    }
-    if(Assembly!=nullptr&&!Assembly->plan.strates.empty()
-        &&!RunCoreFarHorizonAgreementAudit(World,Keys,*Assembly,OutError))return false;
+    if(Assembly!=nullptr&&!Assembly->plan.strates.empty())
+    {
+        if(FParse::Param(FCommandLine::Get(),TEXT("corefeatureauditonly"))
+            &&!RunCoreFarCapTileCensus(World,*Assembly,OutError))return false;
+        if(!RunCoreFarHorizonAgreementAudit(World,Keys,*Assembly,OutError))return false;
+    }
    return true;
 }

@@ -195,7 +195,7 @@ namespace VoxelForgeCore
    // L'assembleur v1 encode coordonnees et scalaires en 1/256 de voxel, independamment des tuiles.
    inline constexpr std::int64_t WorldAssemblySubvoxelsPerVoxel = 256;
    inline constexpr std::uint32_t WorldAssemblySchemaVersion = 1;
-    inline constexpr std::uint32_t WorldAssemblyEvaluatorVersion = 4;
+    inline constexpr std::uint32_t WorldAssemblyEvaluatorVersion = 5;

    enum class FieldChannel : std::uint32_t
    {
@@ -662,6 +662,13 @@ namespace VoxelForgeCore
        bool isValid() const noexcept;
        HeightfieldPointSample point(std::int64_t xSubvoxels, std::int64_t ySubvoxels,
                                     std::int64_t zSubvoxels) const noexcept;
+        // The far render surface is clipped to this strate's owned upper boundary; density stays unchanged.
+        // La surface lointaine est bornee au haut de la strate; la densite reste inchangee.
+        std::int64_t farSurfaceCapHeightSubvoxels(std::int64_t xSubvoxels,
+            std::int64_t ySubvoxels) const noexcept;
+        // Conservative global Z extent of this declared far roof, including biome and cap features.
+        // Bornes Z prudentes du plafond lointain declare, avec les biomes et les fonctions de cap.
+        std::array<std::int64_t, 2> capHeightBounds() const noexcept;
        WorldAssemblyFeatureTileListV1 buildFeatureTileList(
            const std::array<std::int64_t, 3>& tileMinimumSubvoxels,
            const std::array<std::int64_t, 3>& tileMaximumSubvoxels) const;
@@ -995,11 +1002,11 @@ namespace VoxelForgeCore
        // Validation control only; never participates in recipe/world identity.
        // Controle de validation seulement, sans effet sur l'identite du monde.
        bool useAssemblyFeatureQueries = true;
-        // Bump when the far-horizon mesh representation changes. Far tile mesh hashes are
-        // salted with this version; density and LOD0-3 hashes are intentionally unchanged.
-        // Incremente quand la representation d'horizon lointain change; les hashes de maillage
-        // lointain incluent cette version, sans toucher a la densite ni aux LOD0-3.
-        std::uint32_t farHorizonVersion = 1;
+        // Bump when the distant cap representation changes. LOD4-8 mesh hashes are salted;
+        // density and LOD0-3 hashes remain unchanged.
+        // Incremente quand le plafond lointain change. Les hashes LOD4-8 incluent cette version;
+        // densite et hashes LOD0-3 restent inchanges.
+        std::uint32_t farHorizonVersion = 2;
    };

    class VFCORE_API World
@@ -10,6 +10,7 @@
 #include <chrono>
 #include <unordered_map>
 #include <unordered_set>
+#include <set>

 namespace vfcore::detail
 {
@@ -331,11 +332,11 @@ namespace VoxelForgeCore

            for(const auto& Plan:Manifest.plan.strates)
            {
+                const VoxelForgeCore::Heightfield2D Block(Manifest.recipe,Plan);
+                if(!Block.isValid())continue;
                const int64 StratumMinZ=static_cast<int64>(Plan.bottomChunkZ)*CHUNK_SIZE*Scale;
                const int64 StratumMaxZ=(static_cast<int64>(Plan.topChunkZ)+1)*CHUNK_SIZE*Scale;
                if(TileMaxZ<StratumMinZ||TileMinZ>StratumMaxZ)continue;
-                const VoxelForgeCore::Heightfield2D Block(Manifest.recipe,Plan);
-                if(!Block.isValid())continue;
                struct FGridSample
                {
                    double Ground=0.0,Cap=0.0;
@@ -576,10 +577,10 @@ namespace VoxelForgeCore
            const WorldAssemblyManifest& Manifest,const FVoxelTileKey& Key,FVoxelMeshData& Mesh)
        {
            FNativeCapRefinementStats Stats;
-            if(Key.Level<5||!Owner.Generator)return Stats;
-            constexpr int32 GridStepVoxels=128;
+            if(Key.Level<4||!Owner.Generator)return Stats;
+            const int32 GridStepVoxels=Key.Level<5?std::min(128,1<<Key.Level):128;
            constexpr int64 Scale=WorldAssemblySubvoxelsPerVoxel;
-            constexpr int64 GridStepSubvoxels=GridStepVoxels*Scale;
+            const int64 GridStepSubvoxels=static_cast<int64>(GridStepVoxels)*Scale;
            const FIntVector TileOrigin=Key.OriginVoxels();
            const int32 TileExtent=Key.ExtentVoxels();
            if(TileExtent<=0||TileExtent%GridStepVoxels!=0)return Stats;
@@ -599,11 +600,10 @@ namespace VoxelForgeCore

            for(const auto& Plan:Manifest.plan.strates)
            {
-                const int64 StratumMinZ=static_cast<int64>(Plan.bottomChunkZ)*CHUNK_SIZE*Scale;
-                const int64 StratumMaxZ=(static_cast<int64>(Plan.topChunkZ)+1)*CHUNK_SIZE*Scale;
-                if(TileMaxZ<StratumMinZ||TileMinZ>StratumMaxZ)continue;
                const VoxelForgeCore::Heightfield2D Block(Manifest.recipe,Plan);
                if(!Block.isValid())continue;
+                const auto CapHeightBounds=Block.capHeightBounds();
+                if(TileMaxZ<CapHeightBounds[0]||TileMinZ>CapHeightBounds[1])continue;

                struct FGridSample
                {
@@ -623,7 +623,7 @@ namespace VoxelForgeCore
                    const auto Column=Block.point(XSub,YSub,0);
                    auto& Sample=Grid[GridIndex(X,Y)];
                    Sample.Ground=static_cast<double>(Column.groundHeightSubvoxels);
-                    Sample.Cap=static_cast<double>(Column.capHeightSubvoxels);
+                    Sample.Cap=static_cast<double>(Block.farSurfaceCapHeightSubvoxels(XSub,YSub));
                    int32 Dominant=0,Neighbor=0;float Blend=0.0f;
                    Owner.Generator->GetBiomeMaterialAt(static_cast<float>(XSub)/Scale,
                        static_cast<float>(YSub)/Scale,static_cast<float>(Sample.Cap/Scale),
@@ -1160,6 +1160,71 @@ namespace VoxelForgeCore
        VoxelClipmapDesiredTiles::Build(center,minZ,maxZ,parameters,nativeTiles);
        std::vector<TileKey> tiles;tiles.reserve(static_cast<std::size_t>(nativeTiles.Num()));
        for(const FVoxelTileKey& key:nativeTiles)tiles.push_back(FromNative(key));
+        if(impl_->worldAssembly&&!impl_->worldAssembly->plan.strates.empty())
+        {
+            constexpr std::int64_t SubvoxelsPerVoxel=WorldAssemblySubvoxelsPerVoxel;
+            const auto FloorDiv64=[](std::int64_t Value,std::int64_t Divisor)
+            {
+                const std::int64_t Quotient=Value/Divisor,Remainder=Value%Divisor;
+                return Quotient-((Remainder!=0&&Remainder<0)?1:0);
+            };
+            std::set<std::array<std::int32_t,3>> FarSurfaceColumns;
+            std::set<std::array<std::int32_t,4>> ExistingKeys;
+            for(const TileKey& Key:tiles)
+            {
+                ExistingKeys.insert({Key.coordinate.x,Key.coordinate.y,Key.coordinate.z,Key.lod});
+                if(Key.lod>=4&&Key.lod<=8)
+                    FarSurfaceColumns.insert({Key.coordinate.x,Key.coordinate.y,Key.lod});
+            }
+            for(const auto& Plan:impl_->worldAssembly->plan.strates)
+            {
+                const Heightfield2D Field(impl_->worldAssembly->recipe,Plan);
+                if(!Field.isValid())continue;
+                const auto CapBounds=Field.capHeightBounds();
+                for(const auto& Column:FarSurfaceColumns)
+                {
+                    const std::int32_t Lod=Column[2];
+                    const std::int64_t Extent=static_cast<std::int64_t>(32)<<Lod;
+                    const std::int64_t TileHeightSubvoxels=Extent*SubvoxelsPerVoxel;
+                    const std::int64_t MinimumBand=FloorDiv64(CapBounds[0],TileHeightSubvoxels);
+                    const std::int64_t MaximumBand=FloorDiv64(CapBounds[1],TileHeightSubvoxels);
+                    for(std::int64_t Band=MinimumBand;Band<=MaximumBand;++Band)
+                    {
+                        if(Band<MIN_int32||Band>MAX_int32)continue;
+                        const std::array<std::int32_t,4> Identity={Column[0],Column[1],
+                            static_cast<std::int32_t>(Band),Lod};
+                        if(!ExistingKeys.insert(Identity).second)continue;
+                        const std::int64_t CandidateMinX=static_cast<std::int64_t>(Identity[0])*Extent;
+                        const std::int64_t CandidateMinY=static_cast<std::int64_t>(Identity[1])*Extent;
+                        const std::int64_t CandidateMinZ=
+                            static_cast<std::int64_t>(Identity[2])*Extent;
+                        bool bOverlapsClipmapTile=false;
+                        for(const TileKey& Existing:tiles)
+                        {
+                            const std::int64_t ExistingExtent=static_cast<std::int64_t>(32)<<Existing.lod;
+                            const std::int64_t ExistingMinX=static_cast<std::int64_t>(Existing.coordinate.x)*ExistingExtent;
+                            const std::int64_t ExistingMinY=static_cast<std::int64_t>(Existing.coordinate.y)*ExistingExtent;
+                            const std::int64_t ExistingMinZ=static_cast<std::int64_t>(Existing.coordinate.z)*ExistingExtent;
+                            const bool bOverlapX=ExistingMinX<CandidateMinX+Extent
+                                &&CandidateMinX<ExistingMinX+ExistingExtent;
+                            const bool bOverlapY=ExistingMinY<CandidateMinY+Extent
+                                &&CandidateMinY<ExistingMinY+ExistingExtent;
+                            const bool bOverlapZ=ExistingMinZ<CandidateMinZ+Extent
+                                &&CandidateMinZ<ExistingMinZ+ExistingExtent;
+                            if(bOverlapX&&bOverlapY&&bOverlapZ)
+                            {bOverlapsClipmapTile=true;break;}
+                        }
+                        // Preserve the clipmap's non-overlapping 3D partition.  Where another
+                        // requested tile already occupies this cap volume, that tile owns the
+                        // shared roof surface; never add an overlapping LOD sibling.
+                        // Garder la partition 3D sans recouvrement. Une tuile deja presente
+                        // possede la surface de toit partagee; ne pas ajouter un voisin LOD superpose.
+                        if(bOverlapsClipmapTile)continue;
+                        tiles.push_back({{Identity[0],Identity[1],Identity[2]},Identity[3]});
+                    }
+                }
+            }
+        }
        std::sort(tiles.begin(),tiles.end(),[&](const TileKey& a,const TileKey& b)
        {
            const double da=TileDistanceSquared(a,{center.X,center.Y,center.Z});
@@ -1201,7 +1266,7 @@ namespace VoxelForgeCore
            &&options.mesherRecipe!=MesherRecipe::worldAssemblerHybridV1
            &&options.mesherRecipe!=MesherRecipe::worldAssemblerHybridV2)
        {error="tile mesher recipe version is unsupported";return std::nullopt;}
-        if(level>=5&&options.farHorizonVersion==0)
+        if(level>=4&&options.farHorizonVersion==0)
        {error="far-horizon recipe version must be nonzero";return std::nullopt;}
        TArray<FVoxelHybridSharpFeatureBox> sharpFeatures;
        if(options.mesherRecipe!=MesherRecipe::marchingCubesV1&&level==0&&impl_->worldAssembly)
@@ -1501,7 +1566,7 @@ namespace VoxelForgeCore
            (options.hashDensity||options.captureDensitySamples)?&densityValues:nullptr);
        const double MeshingMilliseconds=std::chrono::duration<double,std::milli>(
            std::chrono::steady_clock::now()-MeshingStart).count();
-        out.diagnostics.farHorizonVersion=key.lod>=5?options.farHorizonVersion:0;
+        out.diagnostics.farHorizonVersion=key.lod>=4?options.farHorizonVersion:0;
        const auto FarShellStart=std::chrono::steady_clock::now();
        const FStandaloneShapeWorld& farShape=tileShape.HasFarWorld()?tileShape:*impl_->shape;
        out.diagnostics.farShellRepairSkipped=bSkipFarShellRepair;
@@ -1533,11 +1598,12 @@ namespace VoxelForgeCore
        }
        out.diagnostics.farShellMilliseconds=std::chrono::duration<double,std::milli>(
            std::chrono::steady_clock::now()-FarShellStart).count();
-        if(impl_->worldAssembly&&key.lod>=5&&!bOverlapsPlayerEdit)
+        if(impl_->worldAssembly&&key.lod>=4&&!bOverlapsPlayerEdit)
        {
            const auto HorizonStart=std::chrono::steady_clock::now();
-            const auto GroundStats=RefineFarNativeGround(
-                world,*impl_->worldAssembly,nativeKey,mesh);
+            FNativeCapRefinementStats GroundStats;
+            if(key.lod>=4)
+                GroundStats=RefineFarNativeGround(world,*impl_->worldAssembly,nativeKey,mesh);
            const auto CapStats=RefineFarNativeCap(world,*impl_->worldAssembly,nativeKey,mesh);
            out.diagnostics.farHorizonMilliseconds=std::chrono::duration<double,std::milli>(
                std::chrono::steady_clock::now()-HorizonStart).count();
@@ -1612,7 +1678,7 @@ namespace VoxelForgeCore
            { densityHash^=std::bit_cast<std::uint32_t>(value);densityHash*=1099511628211ull; }
            out.densityHash=densityHash;out.meshHash=HashViewerMesh(mesh);
            out.payloadHash=HashPayload(mesh);out.topologyHash=HashTopology(mesh);
-            if(key.lod>=5)
+            if(key.lod>=4)
            {
                out.meshHash=SaltFarHorizonHash(out.meshHash,options.farHorizonVersion);
                out.payloadHash=SaltFarHorizonHash(out.payloadHash,options.farHorizonVersion);
@@ -1463,8 +1463,9 @@ namespace world_assembly_detail
            +secondaryHeight*(65536-primaryWeight))/65536;
        out.biomeId=primary->stableId;out.neighborBiomeId=secondary->stableId;
        out.biomeWeightQ16=primaryWeight;
-        out.capHeightSubvoxels=plan.capHeightSubvoxels+MulQ16(plan.capUndulationSubvoxels,
+        std::int64_t cap=plan.capHeightSubvoxels+MulQ16(plan.capUndulationSubvoxels,
            Noise2D(x,y,plan.capWavelengthSubvoxels,recipe.seed,0x4341505f554e4431ull));
+        out.capHeightSubvoxels=cap;
        out.waterSurfaceSubvoxels=plan.waterSurfaceSubvoxels;
        return out;
    }
@@ -1816,6 +1817,65 @@ bool Heightfield2D::isValid() const noexcept
    });
 }

+std::array<std::int64_t,2> Heightfield2D::capHeightBounds() const noexcept
+{
+    if(!isValid())return {0,0};
+    long double Minimum=std::numeric_limits<long double>::infinity();
+    long double Maximum=-std::numeric_limits<long double>::infinity();
+    const auto IncludeBiome=[&](const WorldAssemblyBiomeProfileV1& Biome)
+    {
+        const long double Base=Biome.hasCapProfile
+            ?static_cast<long double>(Biome.capHeightSubvoxels)
+            :static_cast<long double>(plan_->capHeightSubvoxels);
+        const long double Undulation=Biome.hasCapProfile
+            ?static_cast<long double>(Biome.capUndulationSubvoxels)
+            :static_cast<long double>(plan_->capUndulationSubvoxels);
+        const long double Detail=Biome.hasCapProfile
+            ?static_cast<long double>(Biome.capDetailAmplitudeSubvoxels)
+            :static_cast<long double>(plan_->capDetailAmplitudeSubvoxels);
+        const long double Ridge=Biome.hasCapProfile
+            ?static_cast<long double>(Biome.capRidgeAmplitudeSubvoxels)
+            :static_cast<long double>(plan_->capRidgeAmplitudeSubvoxels);
+        Minimum=std::min(Minimum,Base-Undulation-Detail-Ridge);
+        Maximum=std::max(Maximum,Base+Undulation);
+    };
+    if(recipe_->biomes.empty())
+    {
+        const WorldAssemblyBiomeProfileV1 Fallback{};
+        IncludeBiome(Fallback);
+    }
+    else for(const auto& Biome:recipe_->biomes)IncludeBiome(Biome);
+    long double FeatureAmplitude=0.0L;
+    for(const auto& Feature:plan_->features)
+        if(Feature.type==3)
+            FeatureAmplitude+=std::abs(static_cast<long double>(Feature.parametersSubvoxels[0]));
+    Minimum-=FeatureAmplitude;Maximum+=FeatureAmplitude;
+    if(recipe_->evaluatorVersion>=5)
+    {
+        const long double TopSubvoxels=(static_cast<long double>(plan_->topChunkZ)+1.0L)
+            *CoreTileVoxelCount*WorldAssemblySubvoxelsPerVoxel;
+        Minimum=std::min(Minimum,TopSubvoxels);
+        Maximum=std::min(Maximum,TopSubvoxels);
+    }
+    const long double Int64Minimum=static_cast<long double>(std::numeric_limits<std::int64_t>::min());
+    const long double Int64Maximum=static_cast<long double>(std::numeric_limits<std::int64_t>::max());
+    return {static_cast<std::int64_t>(std::clamp(Minimum,Int64Minimum,Int64Maximum)),
+        static_cast<std::int64_t>(std::clamp(Maximum,Int64Minimum,Int64Maximum))};
+}
+
+std::int64_t Heightfield2D::farSurfaceCapHeightSubvoxels(std::int64_t x,
+    std::int64_t y) const noexcept
+{
+    if(!isValid())return 0;
+    const HeightfieldPointSample column=point(x,y,0);
+    if(recipe_->evaluatorVersion<5)return column.capHeightSubvoxels;
+    // Clip only the far render surface. Keep the near density evaluator bit-identical.
+    // Borner uniquement le plafond lointain. L'evaluateur de densite proche reste identique.
+    const std::int64_t ownedUpperBoundary=(static_cast<std::int64_t>(plan_->topChunkZ)+1)
+        *CoreTileVoxelCount*WorldAssemblySubvoxelsPerVoxel;
+    return std::min(column.capHeightSubvoxels,ownedUpperBoundary);
+}
+
 WorldAssemblyFeatureTileListV1 Heightfield2D::buildFeatureTileList(
    const std::array<std::int64_t,3>& minimum,
    const std::array<std::int64_t,3>& maximum) const
@@ -76,6 +76,25 @@ Nothing about the brief or the order of your runs made this round harder. The se

 — Luna

+
+## World assembler S4 / M3 Round 8 — 2026-10-19
+
+SurfaceWorld's distant ceiling now uses the shared planar heightfield and closes at its owning
+strate boundary. The owner walk census emits all 385/385 requested cap bands; 128-point agreement is
+within 0.0504 cm, the 100 cm negative control fails as intended, and all 2,520 upward rays hit the
+roof. LOD0–LOD3 hashes remain identical to S3/S2. Warmed SurfaceWorld LOD7/8 p95 changes are +0.03%
+and +0.11%; the full cold clipmap adds 132 ms. The far-cliff fluting is coarse 64/128 m MC sampling,
+so it remains open rather than multiplying mesh work by about eight.
+
+Core-off, both M2 fixture sets, and staged SurfaceWorld/FloatingIslands checks pass at the requested
+scales. FloatingIslands has no planar cap and correctly leaves open sky above an open-air island.
+Captures, hashes, failure ledger and source/compile list are in
+[`WorldAssemblerM3/Round8/REPORT.md`](../../WorldAssemblerM3/Round8/REPORT.md). CODEMAP section 3 and
+ARCHITECTURE section 8.25 are updated. No new source file, owner asset edit, commit, push or stash.
+
+— Luna
+
+
 ## Claude, after step 26 (2026-10-08, night)
 Thank you, Luna. Naming `DEVICE_HUNG` down to the tile and the slot was the best kind of answer:
 the owner's PC has had unexplained hard reboots, and "it was our out-of-bounds copy, in an audit-only
@@ -0,0 +1,137 @@
+# World assembler S4 / M3 Round 8
+
+Date: 2026-10-19. Base: S3 / `d0f97bf`. No commit, push or stash.
+
+## Result
+
+SurfaceWorld now has a continuous far ceiling at LOD5–8, projected from the same declared planar
+heightfield and closed at the owning strate's upper boundary. The staged owner's real plan and walk
+view pass cap census, root agreement and upward-ray coverage. LOD0–LOD3 hashes still match S3 and S2.
+The far recipe is version 2. FloatingIslands still shows open sky overhead; it has no declared planar
+cap, and that is expected for an open-air island strate.
+
+## Count first: why S3 looked detached
+
+The pre-fix owner-camera audit found 361 far XY tiles and 786,153 profile samples; all profile samples
+had a roof. Of 401 cap bands requested, 401 emitted triangles, with 0 requested bands empty and 0
+clipmap culls. So the proposed ground-height gate was not leaving requested cap bands unmeshed on this
+walk view. The 128-point cap-to-near-root check did fail: maximum vertical error was 823.8525 cm
+(one sample was -447.0469 voxels at the far cap versus -480.001 at the near root). The failure was
+the cap datum sitting above its owning boundary, which made the roof read as detached pieces. The
+128-voxel lattice itself was not leaving empty bands.
+
+The fix is a render-surface projection to `(topChunkZ + 1) * 32` voxels, the owning strate's upper
+boundary. `Heightfield2D::point()` and density values remain unchanged. The far cap and its bounds use
+the shared projected height; the tile selector adds only non-overlapping cap bands. All samples use a
+global XY lattice so neighboring cap tiles share edges. LOD4 uses a 16-voxel grid step; LOD5–8 use
+128 voxels.
+
+Post-fix audit: 385/385 requested cap bands emitted positive-area triangles (LOD4 88/88, LOD5 48/48,
+LOD6 48/48, LOD7 48/48, LOD8 153/153); 0 empty and 0 culled. Across 128 shared XY points, far cap to
+near-root error is at most 0.0504 cm (2 cm tolerance). A 100 cm datum-offset negative control measured
+100.0015 cm and was detected. The S3 ground agreement still passes: max LOD7/8 to near-root error
+0.0427 cm, cross-LOD error 0, and its 100 cm control is detected.
+
+Coverage uses emitted cap triangles, not the height profile alone. At each of 33 owner route points
+and two camera points, 72 upward rays span elevations 5, 10, 12, 15, 30, 45, 60, 75 and 90 degrees
+over eight azimuths. Result: 2,520/2,520 hit the cap before the far clip or clipmap edge (100%);
+0 profile-roof, mesh or clip-edge misses. All 35 points individually reached 100%. This verifies the
+owner route and camera samples, not every possible point in the full strate volume.
+
+## Visuals and fluting
+
+Matched captures use the Round 7 views, the same staged plan and camera positions, 60 fps/VSync, and
+the viewer closed after capture. Each S4 JPEG is 640x400 and under 19 KB.
+
+| View | S3 | S4 | Readout |
+|---|---|---|---|
+| Owner walk horizon | [S3](../Round7/captures/after_s3_surface.jpg) | [S4](captures/s4_walk_horizon.jpg) | Walk horizon view after cap repair. |
+| Cap at distance | [S3](../Round7/captures/after_s3_cap.jpg) | [S4](captures/s4_cap_distance.jpg) | The isolated-looking pieces are gone. |
+| Far view, y=-1800 m | [S3](../Round7/captures/after_s3_far.jpg) | [S4](captures/s4_far_y_minus_1800.jpg) | Far-cliff fluting remains. |
+| Looking straight up, far distance | — | [S4](captures/s4_far_straight_up.jpg) | Dark and low contrast; geometry/ray audit establishes the roof, pixels alone do not distinguish roof from dark sky. |
+
+Fluting is coarse marching-cubes sampling on steep ground faces. Each far tile spans 16 coarse cells
+per side: at 25 cm, LOD7's step is 256 voxels (64 m), LOD8's is 512 voxels (128 m). The strips cross
+tile faces rather than appearing only at LOD seams; they predate S4 in S2/S3. Certified SurfaceWorld
+tiles skip shell repair, native replacement affects upward-facing ground only, and this is not a
+normal or backface-culling artifact. Refining all steep faces would multiply far 3D mesh work by
+roughly eight; that is not a cheap shared fix, so S4 leaves it open.
+
+## Timing, determinism and regression checks
+
+SurfaceWorld timings are warmed p95s over the same eight staged 25 cm owner keys per LOD as S3.
+Runs were serial at normal priority with no overlapping build or Unreal process. These are tile times,
+not frame times.
+
+| LOD | S3 full p95 | S4 full p95 | Delta |
+|---:|---:|---:|---:|
+| 7 | 19.801 ms | 19.8069 ms | +0.0059 ms (+0.03%) |
+| 8 | 58.346 ms | 58.4113 ms | +0.0653 ms (+0.11%) |
+
+The standalone cold full-clipmap benchmark took 3.107 s versus S3's 2.975 s on the same 2,553-tile,
+12-worker workload: +132 ms (+4.4%). Far closure is therefore effectively flat in warmed owner tile
+p95, with a small whole-clipmap cost. LOD8 cap refinement covered 385 tiles / 757,540 grid cells and
+generated 1,515,082 cap triangles.
+
+* SurfaceWorld BuildHost at 25 cm: PASS; W1/W8/W16 stable at density `0cd2a1a4152ee4aa`, mesh
+  `80a5b054b904b1a2`, payload `bf2f1b40dff38acc`, topology `56074198682d5e18`.
+* FloatingIslands BuildHost at 25 cm: PASS; W1/W8/W16 stable and standalone hashes match. Its plan
+  contains 4 islands, 3 connectors and 28 route segments; water remains fixed.
+* Core off / legacy at 12.5 cm: PASS.
+* M2 HybridV1 and HybridV2 fixtures at 25 cm: PASS; each reports five analytic fixtures and one
+  border fixture.
+* Standalone W1/W8/W16 determinism: PASS. Owner clipmap density hash remains
+  `c10697a8f48380c7`.
+* LOD0–LOD3 hashes match S3 and S2 exactly:
+
+| LOD | Density | Mesh | Payload | Topology |
+|---:|---|---|---|---|
+| 0 | `769f2a706d585a72` | `33eeeb39fa443816` | `645621a1d968983f` | `c2457ed905036c9d` |
+| 1 | `69cc5a5c0a2c60af` | `b48335f5410c57d5` | `d15c5480162ab8ba` | `feca1bd025823604` |
+| 2 | `85deed5683a77202` | `53469895987aeea2` | `e55f8ae7e1532033` | `d5feb12a0e85c09b` |
+| 3 | `6518caefb3be7e7f` | `ec513c90b853a614` | `f62fa1137ff17f82` | `ccf1dcf681965816` |
+
+Far output changes are salted by far recipe v2 in mesh, payload and topology hashes from LOD4 upward.
+The final Standalone build and BuildHost Core compile/link-safety check pass. The editor commandlet
+uses explicit RealtimeMesh section ranges for cap-only and ground/cap tiles. Final reruns had no
+ensure. No new `UECC-*` folder appeared; the only crash directory is the pre-existing 2026-09-17
+folder. No run hit
+`0xC0000142`; all commandlets stayed below 4 GiB peak private memory. The surface commandlet was the
+longest run at about 10 minutes, within the 15-minute limit.
+
+The Standalone build also printed nonfatal environment/compiler warnings: `vswhere.exe` was not
+recognized by the build script, and C4838 remains at `VoxelStrateManager.cpp:3974–3975`.
+
+### Failed and retried runs
+
+* The first post-fix coverage pass used a camera above the roof and reported 97.143% (72 rays, all
+  misses from that invalid origin). Re-running from the staged owner walk height passed 100%.
+* The first clamp used the wrong chunk boundary and altered point density, changing the LOD3 density
+  hash. It was corrected to the upper boundary and render-only API; final LOD0–LOD3 hashes match S3.
+* One hash invocation omitted `--stream-benchmark` and entered the interactive viewer; it was stopped
+  after 146 s and rerun with the correct mode. An absolute capture output path was split at the
+  workspace spaces by `Start-Process`; relative paths worked. A JPEG helper syntax error was corrected.
+* An early BuildHost mesh apply raised an ensure when a cap material section did not yet exist.
+  Explicit `CreateSection` ranges fixed it; final SurfaceWorld and fixture runs pass without a new
+  crash or ensure. No `0xC0000142` retry was needed.
+
+## Source and compile spots
+
+No new source file was added. Modified sources:
+
+* `Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h`,
+  `Standalone/Core/src/WorldAssemblerInternal.h`, `Standalone/Core/src/VoxelForgeCore.cpp` — shared
+  cap declaration API, clipped render surface, conservative bounds, cap tile selection/emission,
+  and far recipe version; compile through the Standalone Core build and BuildHost Core.
+* `Source/VoxelForgeEditor/Private/VoxelForgeExploreCommandlet.cpp` — owner cap census, agreement and
+  ray coverage audit; compile through the editor module / BuildHost commandlet.
+* `Source/VoxelForge/Private/VoxelWorld.cpp` — explicit realtime mesh section ranges; compile through
+  the VoxelForge runtime module.
+* `Standalone/Source/StandaloneViewer.cpp` — standalone audit and matched capture support; compile
+  through `Standalone/Build.ps1 -Target All`.
+
+`CODEMAP.md` section 3 and `ARCHITECTURE.md` section 8.25 are updated. The API leaves the roof family
+choice in the declared plan, so future cave-in-mountain families can get a far roof by declaring one;
+no SurfaceWorld-only geometry rule is required. The owner need not change assets or settings: keep
+Core enabled at 25 cm. Sprint streaming order and the 1.57 s cold-view target were not changed or
+re-measured.
@@ -22,6 +22,7 @@
 #include <windowsx.h>

 #include <atomic>
+#include <array>
 #include <bit>
 #include <complex>
 #include <cstdio>
@@ -37,6 +38,7 @@
 #include <mutex>
 #include <numeric>
 #include <optional>
+#include <set>
 #include <sstream>
 #include <thread>
 #include <unordered_map>
@@ -8311,8 +8313,435 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
        return true;
    }

+    bool RunWorldAssemblerCapAudit(FStandaloneOwnerWorld& owner,
+        const VoxelForgeCore::ResolvedWorldSnapshot& snapshot,VoxelForgeCore::World& world,
+        VoxelForgeCore::Vec3d walkCameraVoxels)
+    {
+        // This audit follows the shipped owner manifest and Core clipmap, not the transient BuildHost fixture.
+        // Cet audit suit le manifeste owner livre et le clipmap Core, pas le fixture BuildHost transitoire.
+        constexpr std::int64_t Scale=VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+        constexpr double Pi=3.14159265358979323846;
+        constexpr double RayStepVoxels=128.0;
+        constexpr double AgreementToleranceCm=2.0;
+        constexpr double NegativeDatumOffsetCm=100.0;
+        using FTileId=std::array<std::int32_t,4>;
+        using FXYLod=std::array<std::int32_t,3>;
+        const double VoxelSizeCm=static_cast<double>(world.configuration().voxelSizeMicrons)/10000.0;
+        const auto IdFor=[](const VoxelForgeCore::TileKey& key)
+        {return FTileId{key.coordinate.x,key.coordinate.y,key.coordinate.z,key.lod};};
+        const auto FloorDiv64=[](std::int64_t value,std::int64_t divisor)
+        {
+            const std::int64_t quotient=value/divisor,remainder=value%divisor;
+            return quotient-((remainder!=0&&remainder<0)?1:0);
+        };
+        const auto* manifest=snapshot.worldAssembly();
+        if(!manifest||manifest->plan.strates.empty())
+        {std::fprintf(stderr,"[WorldAssemblerFarCapAudit] no SurfaceWorld plan; status=FAIL\n");return false;}
+        const auto planIt=std::find_if(manifest->plan.strates.begin(),manifest->plan.strates.end(),
+            [](const auto& plan){return !plan.route.empty();});
+        if(planIt==manifest->plan.strates.end())
+        {std::fprintf(stderr,"[WorldAssemblerFarCapAudit] no authored walk route; status=FAIL\n");return false;}
+        const auto& plan=*planIt;
+        const VoxelForgeCore::Heightfield2D field(manifest->recipe,plan);
+        if(!field.isValid())
+        {std::fprintf(stderr,"[WorldAssemblerFarCapAudit] invalid Heightfield2D; status=FAIL\n");return false;}
+
+        struct FView
+        {
+            VoxelForgeCore::Vec3d Origin{};
+            std::vector<VoxelForgeCore::TileKey> Keys;
+            std::set<FTileId> KeySet;
+            VoxelForgeCore::TileGenerationOptions Options;
+            double ClipMinX=std::numeric_limits<double>::infinity();
+            double ClipMinY=std::numeric_limits<double>::infinity();
+            double ClipMaxX=-std::numeric_limits<double>::infinity();
+            double ClipMaxY=-std::numeric_limits<double>::infinity();
+            double ClipMaxZ=-std::numeric_limits<double>::infinity();
+        };
+        const auto MakeView=[&](VoxelForgeCore::Vec3d origin)
+        {
+            FView view;view.Origin=origin;
+            const FStandaloneDesiredTileSet native=StandaloneWorldMesher::BuildDesiredSet(owner,
+                FVector(origin.x,origin.y,origin.z));
+            view.Options.bandMinZVoxel=native.bHasStrate
+                ?native.StrateBottomChunkZ*CHUNK_SIZE:MIN_int32;
+            view.Options.bandMaxZVoxel=native.bHasStrate
+                ?(native.StrateTopChunkZ+1)*CHUNK_SIZE:MAX_int32;
+            view.Keys=world.desiredTiles(origin);
+            for(const auto& key:view.Keys)
+            {
+                view.KeySet.insert(IdFor(key));
+                const double extent=static_cast<double>(CHUNK_SIZE<<key.lod);
+                view.ClipMaxZ=std::max(view.ClipMaxZ,(key.coordinate.z+1.0)*extent);
+                if(key.lod<4||key.lod>8)continue;
+                view.ClipMinX=std::min(view.ClipMinX,key.coordinate.x*extent);
+                view.ClipMinY=std::min(view.ClipMinY,key.coordinate.y*extent);
+                view.ClipMaxX=std::max(view.ClipMaxX,(key.coordinate.x+1.0)*extent);
+                view.ClipMaxY=std::max(view.ClipMaxY,(key.coordinate.y+1.0)*extent);
+            }
+            return view;
+        };
+        const FView cameraView=MakeView(walkCameraVoxels);
+        std::set<FXYLod> farXY;
+        for(const auto& key:cameraView.Keys)
+            if(key.lod>=4&&key.lod<=8)farXY.insert({key.coordinate.x,key.coordinate.y,key.lod});
+        std::set<FTileId> capBands;
+        std::uint64_t profileSamples=0,profileSamplesWithoutRoof=0;
+        for(const FXYLod& xy:farXY)
+        {
+            const std::int32_t lod=xy[2];
+            const std::int64_t extent=static_cast<std::int64_t>(CHUNK_SIZE)<<lod;
+            const std::int64_t originX=static_cast<std::int64_t>(xy[0])*extent;
+            const std::int64_t originY=static_cast<std::int64_t>(xy[1])*extent;
+            const std::int64_t gridStep=lod<5?std::min<std::int64_t>(128,1ll<<lod):128;
+            for(std::int64_t y=0;y<=extent;y+=gridStep)
+            for(std::int64_t x=0;x<=extent;x+=gridStep)
+            {
+                ++profileSamples;
+                const auto column=field.point((originX+x)*Scale,(originY+y)*Scale,0);
+                const std::int64_t farCap=field.farSurfaceCapHeightSubvoxels(
+                    (originX+x)*Scale,(originY+y)*Scale);
+                if(farCap<=column.groundHeightSubvoxels)
+                {++profileSamplesWithoutRoof;continue;}
+                const std::int64_t band=FloorDiv64(farCap,extent*Scale);
+                if(band>=MIN_int32&&band<=MAX_int32)
+                    capBands.insert({xy[0],xy[1],static_cast<std::int32_t>(band),lod});
+                if(farCap%(extent*Scale)==0&&band>MIN_int32)
+                    capBands.insert({xy[0],xy[1],static_cast<std::int32_t>(band-1),lod});
+            }
+        }
+
+        struct FAgreement {std::int64_t X=0,Y=0;double FarZ=0.0;};
+        struct FGeometry
+        {
+            std::vector<std::array<VoxelForgeCore::Vec3d,3>> DownwardTriangles;
+            std::uint64_t CapTriangles=0;
+            std::vector<FAgreement> AgreementVertices;
+        };
+        constexpr std::int64_t AgreementGrid=128*Scale;
+        std::map<FTileId,FGeometry> geometryCache;
+        std::string coreError;
+        const auto GetGeometry=[&](const FTileId& id,const VoxelForgeCore::TileGenerationOptions& options)
+            ->const FGeometry*
+        {
+            if(const auto found=geometryCache.find(id);found!=geometryCache.end())return &found->second;
+            const VoxelForgeCore::TileKey key{{id[0],id[1],id[2]},id[3]};
+            const auto mesh=world.generateTile(key,options,coreError);
+            if(!mesh)return nullptr;
+            FGeometry geometry;
+            geometry.CapTriangles=mesh->diagnostics.horizonCapTriangles;
+            const std::size_t capIndexStart=mesh->indices.size()
+                -static_cast<std::size_t>(geometry.CapTriangles)*3u;
+            for(std::size_t index=0;index+2<mesh->indices.size();index+=3)
+            {
+                const auto ia=mesh->indices[index],ib=mesh->indices[index+1],ic=mesh->indices[index+2];
+                if(ia>=mesh->vertices.size()||ib>=mesh->vertices.size()||ic>=mesh->vertices.size())continue;
+                const auto& a=mesh->vertices[ia];const auto& b=mesh->vertices[ib];const auto& c=mesh->vertices[ic];
+                if((a.normal.z+b.normal.z+c.normal.z)/3.0>=-0.05)continue;
+                geometry.DownwardTriangles.push_back({
+                    VoxelForgeCore::Vec3d{a.position.x/VoxelSizeCm,a.position.y/VoxelSizeCm,a.position.z/VoxelSizeCm},
+                    VoxelForgeCore::Vec3d{b.position.x/VoxelSizeCm,b.position.y/VoxelSizeCm,b.position.z/VoxelSizeCm},
+                    VoxelForgeCore::Vec3d{c.position.x/VoxelSizeCm,c.position.y/VoxelSizeCm,c.position.z/VoxelSizeCm}});
+            }
+            for(std::size_t index=capIndexStart;index<mesh->indices.size();++index)
+            {
+                const std::uint32_t vertexIndex=mesh->indices[index];
+                if(vertexIndex>=mesh->vertices.size())continue;
+                const auto& vertex=mesh->vertices[vertexIndex];
+                if(vertex.normal.z>=-0.35)continue;
+                const std::int64_t x=static_cast<std::int64_t>(std::llround(
+                    vertex.position.x/VoxelSizeCm*Scale));
+                const std::int64_t y=static_cast<std::int64_t>(std::llround(
+                    vertex.position.y/VoxelSizeCm*Scale));
+                if(x%AgreementGrid!=0||y%AgreementGrid!=0)continue;
+                geometry.AgreementVertices.push_back({x,y,vertex.position.z/VoxelSizeCm});
+            }
+            return &geometryCache.emplace(id,std::move(geometry)).first->second;
+        };
+
+        std::uint64_t requested=0,emitted=0,requestedWithoutTriangles=0,culled=0;
+        std::uint64_t zeroAreaBoundaryTouches=0,unexplainedEmptyBands=0;
+        std::map<std::int32_t,std::array<std::uint64_t,4>> byLod;
+        std::set<std::pair<std::int64_t,std::int64_t>> agreementXY;
+        std::vector<FAgreement> agreementSamples;agreementSamples.reserve(128);
+        for(const FTileId& id:capBands)
+        {
+            auto& count=byLod[id[3]];++count[0];
+            if(!cameraView.KeySet.contains(id)){++culled;++count[1];continue;}
+            ++requested;
+            const FGeometry* geometry=GetGeometry(id,cameraView.Options);
+            if(geometry==nullptr)
+            {
+                std::fprintf(stderr,"[WorldAssemblerFarCapAudit] tile generation failed key=(%d,%d,%d,lod%d): %s\n",
+                    id[0],id[1],id[2],id[3],coreError.c_str());return false;
+            }
+            if(geometry->CapTriangles==0)
+            {
+                ++requestedWithoutTriangles;++count[3];
+                const std::int64_t extent=static_cast<std::int64_t>(VoxelForgeCore::CoreTileVoxelCount)<<id[3];
+                const std::int64_t step=id[3]<5?std::min<std::int64_t>(128,1ll<<id[3]):128;
+                const std::int64_t minZ=static_cast<std::int64_t>(id[2])*extent*Scale;
+                const std::int64_t maxZ=minZ+extent*Scale;
+                const std::int64_t originX=static_cast<std::int64_t>(id[0])*extent;
+                const std::int64_t originY=static_cast<std::int64_t>(id[1])*extent;
+                std::uint64_t validSamples=0,boundarySamples=0,interiorSamples=0;
+                for(std::int64_t y=0;y<=extent;y+=step)
+                for(std::int64_t x=0;x<=extent;x+=step)
+                {
+                    const auto column=field.point((originX+x)*Scale,(originY+y)*Scale,0);
+                    const std::int64_t farCap=field.farSurfaceCapHeightSubvoxels(
+                        (originX+x)*Scale,(originY+y)*Scale);
+                    if(farCap<=column.groundHeightSubvoxels||farCap<minZ||farCap>maxZ)continue;
+                    ++validSamples;
+                    if(farCap==minZ||farCap==maxZ)++boundarySamples;
+                    else ++interiorSamples;
+                }
+                const bool zeroAreaTouch=validSamples>0&&boundarySamples==validSamples
+                    &&interiorSamples==0;
+                if(zeroAreaTouch)++zeroAreaBoundaryTouches;else ++unexplainedEmptyBands;
+                std::printf("[WorldAssemblerFarCapEmptyBand] key=(%d,%d,%d,lod%d) valid_profile_samples=%llu boundary_samples=%llu interior_samples=%llu classification=%s\n",
+                    id[0],id[1],id[2],id[3],static_cast<unsigned long long>(validSamples),
+                    static_cast<unsigned long long>(boundarySamples),static_cast<unsigned long long>(interiorSamples),
+                    zeroAreaTouch?"zero_area_boundary_touch":"UNEXPLAINED");
+                continue;
+            }
+            ++emitted;++count[2];
+            for(const FAgreement& sample:geometry->AgreementVertices)
+            {
+                if(agreementSamples.size()>=128)break;
+                if(!agreementXY.insert({sample.X,sample.Y}).second)continue;
+                agreementSamples.push_back(sample);
+            }
+        }
+        std::uint64_t agreementCompared=0;
+        double maximumAgreementCm=0.0,maximumNegativeControlCm=0.0;
+        FAgreement maximumAgreementSample{};double maximumAgreementNearRoot=0.0;
+        for(const FAgreement& sample:agreementSamples)
+        {
+            const auto column=field.point(sample.X,sample.Y,0);
+            const std::int64_t farCap=field.farSurfaceCapHeightSubvoxels(sample.X,sample.Y);
+            if(farCap<=column.groundHeightSubvoxels)continue;
+            const double x=static_cast<double>(sample.X)/Scale,y=static_cast<double>(sample.Y)/Scale;
+            const double capVoxel=static_cast<double>(farCap)/Scale;
+            bool foundRoot=false;double nearRoot=0.0;
+            for(double radius=4.0;radius<=4096.0;radius*=2.0)
+            {
+                double lo=capVoxel-radius,hi=capVoxel+radius;
+                if(!(world.densityAt({x,y,lo})>=0.0f&&world.densityAt({x,y,hi})<0.0f))continue;
+                for(int iteration=0;iteration<16;++iteration)
+                {const double mid=(lo+hi)*0.5;if(world.densityAt({x,y,mid})>=0.0f)lo=mid;else hi=mid;}
+                nearRoot=(lo+hi)*0.5;foundRoot=true;break;
+            }
+            if(!foundRoot)continue;
+            const double sampleErrorCm=std::abs(sample.FarZ-nearRoot)*VoxelSizeCm;
+            if(sampleErrorCm>maximumAgreementCm)
+            {maximumAgreementCm=sampleErrorCm;maximumAgreementSample=sample;maximumAgreementNearRoot=nearRoot;}
+            maximumNegativeControlCm=std::max(maximumNegativeControlCm,
+                std::abs(sample.FarZ+NegativeDatumOffsetCm/VoxelSizeCm-nearRoot)*VoxelSizeCm);
+            ++agreementCompared;
+        }
+        if(agreementCompared>0)
+        {
+            const double capVoxel=static_cast<double>(field.farSurfaceCapHeightSubvoxels(
+                maximumAgreementSample.X,maximumAgreementSample.Y))/Scale;
+            const double x=static_cast<double>(maximumAgreementSample.X)/Scale;
+            const double y=static_cast<double>(maximumAgreementSample.Y)/Scale;
+            std::printf("[WorldAssemblerFarCapAgreementMax] xy_vox=(%.1f,%.1f) profile_cap_vox=%.4f far_cap_vox=%.4f near_root_vox=%.4f density_at_cap=%.4f density_below=%.4f density_above=%.4f\n",
+                x,y,capVoxel,maximumAgreementSample.FarZ,maximumAgreementNearRoot,
+                world.densityAt({x,y,capVoxel}),world.densityAt({x,y,capVoxel-4.0}),
+                world.densityAt({x,y,capVoxel+4.0}));
+        }
+        const bool negativeControlDetected=agreementCompared>0
+            &&maximumNegativeControlCm>AgreementToleranceCm;
+        std::printf("[WorldAssemblerFarCapCensus] view=owner_camera far_xy_tiles=%zu profile_samples=%llu samples_without_roof=%llu cap_bands=%zu requested=%llu emitted=%llu requested_without_triangles=%llu zero_area_boundary_touches=%llu unexplained_empty_bands=%llu culled_by_clipmap=%llu\n",
+            farXY.size(),static_cast<unsigned long long>(profileSamples),
+            static_cast<unsigned long long>(profileSamplesWithoutRoof),capBands.size(),
+            static_cast<unsigned long long>(requested),static_cast<unsigned long long>(emitted),
+            static_cast<unsigned long long>(requestedWithoutTriangles),
+            static_cast<unsigned long long>(zeroAreaBoundaryTouches),
+            static_cast<unsigned long long>(unexplainedEmptyBands),static_cast<unsigned long long>(culled));
+        for(const auto& [lod,count]:byLod)
+            std::printf("[WorldAssemblerFarCapLod] lod=%d cap_bands=%llu culled=%llu emitted=%llu requested_without_triangles=%llu\n",
+                lod,static_cast<unsigned long long>(count[0]),static_cast<unsigned long long>(count[1]),
+                static_cast<unsigned long long>(count[2]),static_cast<unsigned long long>(count[3]));
+        std::printf("[WorldAssemblerFarCapAgreement] status=%s shared_points=%llu max_far_near_cm=%.4f tolerance_cm=%.2f negative_control=100cm_datum_offset max_error_cm=%.4f detected=%d\n",
+            agreementCompared>=32&&maximumAgreementCm<=AgreementToleranceCm&&negativeControlDetected?"PASS":"FAIL",
+            static_cast<unsigned long long>(agreementCompared),maximumAgreementCm,AgreementToleranceCm,
+            maximumNegativeControlCm,negativeControlDetected?1:0);
+
+        constexpr std::array<double,8> azimuths={0.0,45.0,90.0,135.0,180.0,225.0,270.0,315.0};
+        constexpr std::array<double,9> elevations={5.0,10.0,12.0,15.0,30.0,45.0,60.0,75.0,90.0};
+        const auto dot3=[](const VoxelForgeCore::Vec3d& a,const VoxelForgeCore::Vec3d& b)
+        {return a.x*b.x+a.y*b.y+a.z*b.z;};
+        const auto sub3=[](const VoxelForgeCore::Vec3d& a,const VoxelForgeCore::Vec3d& b)
+        {return VoxelForgeCore::Vec3d{a.x-b.x,a.y-b.y,a.z-b.z};};
+        const auto cross3=[](const VoxelForgeCore::Vec3d& a,const VoxelForgeCore::Vec3d& b)
+        {return VoxelForgeCore::Vec3d{a.y*b.z-a.z*b.y,a.z*b.x-a.x*b.z,a.x*b.y-a.y*b.x};};
+        const auto rayTriangle=[&](const VoxelForgeCore::Vec3d& origin,const VoxelForgeCore::Vec3d& direction,
+            const std::array<VoxelForgeCore::Vec3d,3>& triangle,double minDistance,double maxDistance)
+        {
+            const auto edge1=sub3(triangle[1],triangle[0]),edge2=sub3(triangle[2],triangle[0]);
+            const auto p=cross3(direction,edge2);const double determinant=dot3(edge1,p);
+            if(std::abs(determinant)<1.0e-12)return false;
+            const double inverse=1.0/determinant;const auto t=sub3(origin,triangle[0]);
+            const double u=dot3(t,p)*inverse;if(u< -1.0e-8||u>1.0+1.0e-8)return false;
+            const auto q=cross3(t,edge1);const double v=dot3(direction,q)*inverse;
+            if(v< -1.0e-8||u+v>1.0+1.0e-8)return false;
+            const double distance=dot3(edge2,q)*inverse;
+            return distance>=minDistance-1.0e-6&&distance<=maxDistance+1.0e-6;
+        };
+
+        std::vector<VoxelForgeCore::Vec3d> walkOrigins;
+        walkOrigins.reserve(plan.route.size()+1);
+        for(const auto& point:plan.route)
+            walkOrigins.push_back({static_cast<double>(point.positionSubvoxels[0])/Scale,
+                static_cast<double>(point.positionSubvoxels[1])/Scale,
+                static_cast<double>(point.positionSubvoxels[2])/Scale});
+        const auto sameCamera=std::find_if(walkOrigins.begin(),walkOrigins.end(),[&](const auto& point)
+        {return std::abs(point.x-walkCameraVoxels.x)<1.0&&std::abs(point.y-walkCameraVoxels.y)<1.0
+            &&std::abs(point.z-walkCameraVoxels.z)<1.0;});
+        if(sameCamera==walkOrigins.end())walkOrigins.push_back(walkCameraVoxels);
+        const VoxelForgeCore::Vec3d farStraightUpCamera{0.0,-1800.0*4.0,walkCameraVoxels.z};
+        const std::size_t farStraightUpIndex=walkOrigins.size();
+        walkOrigins.push_back(farStraightUpCamera);
+        std::uint64_t rayCount=0,rayHits=0,profileCrossings=0,profileRoofCrossings=0;
+        std::uint64_t missesNoProfileRoof=0,missesMesh=0,missesClipEdge=0;
+        std::array<std::uint64_t,9> raysByElevation{},hitsByElevation{};
+        std::vector<std::string> firstMisses;firstMisses.reserve(8);
+        for(std::size_t viewIndex=0;viewIndex<walkOrigins.size();++viewIndex)
+        {
+            const std::uint64_t hitsBeforeView=rayHits;
+            const std::uint64_t raysBeforeView=rayCount;
+            const auto view=MakeView(walkOrigins[viewIndex]);
+            if(view.ClipMinX>view.ClipMaxX||view.ClipMinY>view.ClipMaxY)continue;
+            const auto startColumn=field.point(
+                static_cast<std::int64_t>(std::llround(view.Origin.x*Scale)),
+                static_cast<std::int64_t>(std::llround(view.Origin.y*Scale)),0);
+            const double startCap=static_cast<double>(field.farSurfaceCapHeightSubvoxels(
+                static_cast<std::int64_t>(std::llround(view.Origin.x*Scale)),
+                static_cast<std::int64_t>(std::llround(view.Origin.y*Scale))))/Scale;
+            for(std::size_t elevationIndex=0;elevationIndex<elevations.size();++elevationIndex)
+            for(const double azimuth:azimuths)
+            {
+                ++rayCount;++raysByElevation[elevationIndex];
+                const double elevation=elevations[elevationIndex]*Pi/180.0;
+                const double radians=azimuth*Pi/180.0;
+                const VoxelForgeCore::Vec3d direction{
+                    std::cos(elevation)*std::cos(radians),std::cos(elevation)*std::sin(radians),std::sin(elevation)};
+                double edgeDistance=std::numeric_limits<double>::infinity();
+                if(direction.x>1.0e-9)edgeDistance=std::min(edgeDistance,(view.ClipMaxX-view.Origin.x)/direction.x);
+                else if(direction.x< -1.0e-9)edgeDistance=std::min(edgeDistance,(view.ClipMinX-view.Origin.x)/direction.x);
+                if(direction.y>1.0e-9)edgeDistance=std::min(edgeDistance,(view.ClipMaxY-view.Origin.y)/direction.y);
+                else if(direction.y< -1.0e-9)edgeDistance=std::min(edgeDistance,(view.ClipMinY-view.Origin.y)/direction.y);
+                if(direction.z>1.0e-9)edgeDistance=std::min(edgeDistance,(view.ClipMaxZ-view.Origin.z)/direction.z);
+                if(!std::isfinite(edgeDistance)||edgeDistance<=0.0)
+                {++missesClipEdge;continue;}
+                bool profileCrossing=false,profileRoof=false;
+                double previousDistance=0.0,previousDelta=view.Origin.z-startCap;
+                for(double distance=std::min(RayStepVoxels,edgeDistance);;)
+                {
+                    const auto column=field.point(
+                        static_cast<std::int64_t>(std::llround((view.Origin.x+direction.x*distance)*Scale)),
+                        static_cast<std::int64_t>(std::llround((view.Origin.y+direction.y*distance)*Scale)),0);
+                    const double cap=static_cast<double>(field.farSurfaceCapHeightSubvoxels(
+                        static_cast<std::int64_t>(std::llround((view.Origin.x+direction.x*distance)*Scale)),
+                        static_cast<std::int64_t>(std::llround((view.Origin.y+direction.y*distance)*Scale))))/Scale;
+                    const double delta=view.Origin.z+direction.z*distance-cap;
+                    if(previousDelta<0.0&&delta>=0.0)
+                    {
+                        const double fraction=-previousDelta/(delta-previousDelta);
+                        const double hitX=view.Origin.x+direction.x*(previousDistance+(distance-previousDistance)*fraction);
+                        const double hitY=view.Origin.y+direction.y*(previousDistance+(distance-previousDistance)*fraction);
+                        const auto hitColumn=field.point(static_cast<std::int64_t>(std::llround(hitX*Scale)),
+                            static_cast<std::int64_t>(std::llround(hitY*Scale)),0);
+                        profileCrossing=true;++profileCrossings;
+                        profileRoof=field.farSurfaceCapHeightSubvoxels(
+                            static_cast<std::int64_t>(std::llround(hitX*Scale)),
+                            static_cast<std::int64_t>(std::llround(hitY*Scale)))
+                            >hitColumn.groundHeightSubvoxels;
+                        if(profileRoof)++profileRoofCrossings;
+                        break;
+                    }
+                    previousDistance=distance;previousDelta=delta;
+                    if(distance>=edgeDistance)break;
+                    distance=std::min(distance+RayStepVoxels,edgeDistance);
+                }
+                bool meshHit=false,intersectedRequestedTile=false,intersectedEmptyTile=false;
+                const auto& rayOrigin=view.Origin;
+                for(const auto& key:view.Keys)
+                {
+                    const double extent=static_cast<double>(CHUNK_SIZE<<key.lod);
+                    const double minBounds[3]={key.coordinate.x*extent,key.coordinate.y*extent,key.coordinate.z*extent};
+                    const double maxBounds[3]={minBounds[0]+extent,minBounds[1]+extent,minBounds[2]+extent};
+                    const double origins[3]={rayOrigin.x,rayOrigin.y,rayOrigin.z};
+                    const double directions[3]={direction.x,direction.y,direction.z};
+                    double enter=0.0,exit=edgeDistance;bool intersects=true;
+                    for(int axis=0;axis<3;++axis)
+                    {
+                        if(std::abs(directions[axis])<1.0e-12)
+                        {if(origins[axis]<minBounds[axis]||origins[axis]>maxBounds[axis]){intersects=false;break;}continue;}
+                        double tNear=(minBounds[axis]-origins[axis])/directions[axis];
+                        double tFar=(maxBounds[axis]-origins[axis])/directions[axis];
+                        if(tNear>tFar)std::swap(tNear,tFar);
+                        enter=std::max(enter,tNear);exit=std::min(exit,tFar);
+                        if(enter>exit){intersects=false;break;}
+                    }
+                    if(!intersects||exit<0.0||enter>edgeDistance)continue;
+                    intersectedRequestedTile=true;
+                    const FGeometry* geometry=GetGeometry(IdFor(key),view.Options);
+                    if(geometry==nullptr)
+                    {std::fprintf(stderr,"[WorldAssemblerFarCapAudit] ray tile generation failed: %s\n",coreError.c_str());return false;}
+                    if(geometry->DownwardTriangles.empty()){intersectedEmptyTile=true;continue;}
+                    for(const auto& triangle:geometry->DownwardTriangles)
+                        if(rayTriangle(rayOrigin,direction,triangle,std::max(0.0,enter),std::min(edgeDistance,exit)))
+                        {meshHit=true;break;}
+                    if(meshHit)break;
+                }
+                if(meshHit){++rayHits;++hitsByElevation[elevationIndex];continue;}
+                if(!profileCrossing||!profileRoof)++missesNoProfileRoof;
+                else ++missesMesh;
+                if(firstMisses.size()<8)
+                {
+                    std::ostringstream message;
+                    message<<"view="<<viewIndex<<" elevation="<<elevations[elevationIndex]
+                        <<" azimuth="<<azimuth<<" profile_crossing="<<(profileCrossing?1:0)
+                        <<" profile_roof="<<(profileRoof?1:0)<<" requested_tile="<<(intersectedRequestedTile?1:0)
+                        <<" empty_tile="<<(intersectedEmptyTile?1:0);
+                    firstMisses.push_back(message.str());
+                }
+            }
+            const char* viewLabel=viewIndex<plan.route.size()?"route_point":
+                (viewIndex==farStraightUpIndex?"far_straight_up":"owner_camera");
+            std::printf("[WorldAssemblerFarCapCoverageView] view=%s index=%zu origin_vox=(%.1f,%.1f,%.1f) rays=%llu hits=%llu coverage_pct=%.3f\n",
+                viewLabel,viewIndex,walkOrigins[viewIndex].x,walkOrigins[viewIndex].y,
+                walkOrigins[viewIndex].z,static_cast<unsigned long long>(rayCount-raysBeforeView),
+                static_cast<unsigned long long>(rayHits-hitsBeforeView),
+                rayCount>raysBeforeView?100.0*static_cast<double>(rayHits-hitsBeforeView)/(rayCount-raysBeforeView):0.0);
+        }
+        std::printf("[WorldAssemblerFarCapCoverage] rays=%llu hits=%llu coverage_pct=%.3f profile_crossings=%llu profile_roof_crossings=%llu misses_no_profile_roof=%llu misses_mesh=%llu misses_clip_edge=%llu view_points=%zu\n",
+            static_cast<unsigned long long>(rayCount),static_cast<unsigned long long>(rayHits),
+            rayCount?100.0*static_cast<double>(rayHits)/rayCount:0.0,
+            static_cast<unsigned long long>(profileCrossings),static_cast<unsigned long long>(profileRoofCrossings),
+            static_cast<unsigned long long>(missesNoProfileRoof),static_cast<unsigned long long>(missesMesh),
+            static_cast<unsigned long long>(missesClipEdge),walkOrigins.size());
+        for(std::size_t i=0;i<elevations.size();++i)
+            std::printf("[WorldAssemblerFarCapCoverageElevation] elevation_deg=%.0f rays=%llu hits=%llu\n",
+                elevations[i],static_cast<unsigned long long>(raysByElevation[i]),
+                static_cast<unsigned long long>(hitsByElevation[i]));
+        for(const auto& miss:firstMisses)std::printf("[WorldAssemblerFarCapCoverageMiss] %s\n",miss.c_str());
+        const bool censusPassing=requested>0&&unexplainedEmptyBands==0&&culled==0;
+        const bool agreementPassing=agreementCompared>=32&&maximumAgreementCm<=AgreementToleranceCm
+            &&negativeControlDetected;
+        const bool coveragePassing=rayCount>0&&rayHits==rayCount;
+        std::printf("[WorldAssemblerFarCapAudit] census=%s agreement=%s coverage=%s status=%s\n",
+            censusPassing?"PASS":"FAIL",agreementPassing?"PASS":"FAIL",
+            coveragePassing?"PASS":"FAIL",censusPassing&&agreementPassing&&coveragePassing?"PASS":"FAIL");
+        return censusPassing&&agreementPassing&&coveragePassing;
+    }
+
    int RunWorldAssemblerAudit(FStandaloneOwnerWorld& owner,
-        const VoxelForgeCore::ResolvedWorldSnapshot& snapshot,const std::string& captureDirectory)
+        const VoxelForgeCore::ResolvedWorldSnapshot& snapshot,const std::string& captureDirectory,
+        VoxelForgeCore::World* compiledWorld,VoxelForgeCore::Vec3d walkCameraVoxels)
    {
        const auto* manifest=snapshot.worldAssembly();
        if(!manifest||manifest->plan.strates.empty())
@@ -8858,9 +9287,11 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
        std::printf("[WorldAssemblerReadiness] local_field_query=%s analytic_collision_validation=%s physics_collision_cooking=deferred_to_Unreal_adapter render_mesh_readiness=reported_by_matched_view_runs\n",
            coreQueryPass?"ready_without_render_meshes":"not_ready",
            routeAudit.passed?"route_sweep_ready":"not_ready");
+        const bool farCapAuditPassing=compiledWorld!=nullptr
+            &&RunWorldAssemblerCapAudit(owner,snapshot,*compiledWorld,walkCameraVoxels);
        return bounds.passed&&shelfThickness.passed&&routeAudit.passed
            &&routeSupportNegativeControl&&cliffRegressionPassing&&seamClassificationPassing
-            &&deterministic&&coreQueryPass?0:11;
+            &&deterministic&&coreQueryPass&&farCapAuditPassing?0:11;
    }
 }

@@ -9254,7 +9685,11 @@ int main(int Argc,char** Argv)
            App.bRoundTunnelEnhanced,Error);
        if(!App.Snapshot)
        {std::fprintf(stderr,"World assembler snapshot setup failed: %s\n",Error.c_str());return 2;}
-        return RunWorldAssemblerAudit(*App.World,App.Snapshot,WorldAssemblyCaptureDir);
+        App.bShapeWorld=true;
+        if(!App.BuildShapeWorldForCamera(Error,true,false,true))
+        {std::fprintf(stderr,"World assembler cap audit shape build failed: %s\n",Error.c_str());return 2;}
+        return RunWorldAssemblerAudit(*App.World,App.Snapshot,WorldAssemblyCaptureDir,
+            App.ShapeWorld.get(),{App.Position.X*4.0,App.Position.Y*4.0,App.Position.Z*4.0});
    }
    const bool bNeedFarShapeWorld=bStreamBenchmark
        ?(StreamBenchmarkMaxLevel<0||StreamBenchmarkMaxLevel>=App.World->FullResClipLevels)