wip(assembler): M1 repair round -- raised block and cliff fixed; native 7x faster than legacy

Luna, M1 repair round: the rectangular raised block and the broken cliff shared one cause,
a type-2 solid AABB in the generated plan; it is now a tapered, terrain-following shelf, and
a negative-control audit catches the old box behaviour; seam classification check passes.
Bound audit 298 boxes / 8,046 samples, 0 misses. Evaluator and 120-tile density/mesh/payload/
topology hashes identical at W1/W8/W16. Cave regression: walkability 5,642/5,642, 64/64 tiles.
Legacy mismatch unchanged (0 biome mismatches, 18.14% signs).
Speed (matched workloads): 120-tile full detail 0.089 s native vs 0.625 s legacy; 529-tile
clipmap 3.858 s vs 11.687 s -- 2.29 s above the ~1.57 s aim; LOD8 dominates (165 unknown
tiles, 13.27 M field calls, 10.88 M column-cache misses).
My capture review: coast matches legacy closely; surface clean but a dark flat slab on the far
horizon; cliff shelf renders as a stack of thin plates with back faces showing (sub-voxel
shelf thickness suspected).

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

Standalone/Source/StandaloneViewer.cpp

@@ -6919,6 +6919,10 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
         std::vector<FHashedTile> DensityRows,MeshRows,PayloadRows,TopologyRows;
         int32 Finished=0,NeighborhoodFinished=0,FullDetailFinished=0;
         int32 FullDetailExpected=0;
+        uint64 NativeSolidBoxes=0,NativeAirBoxes=0,NativeMixedBoxes=0,NativeUnknownBoxes=0;
+        uint64 NativeFieldCalls=0,NativeColumnHits=0,NativeColumnMisses=0,NativeMeshingSkips=0;
+        double NativeClassificationMilliseconds=0.0,NativeColumnComputeMilliseconds=0.0;
+        double NativeMeshingMilliseconds=0.0;
         for(const FVoxelTileKey& Tile:Desired.Tiles)
             if(Tile.Level<World.FullResClipLevels)++FullDetailExpected;
         Clock::time_point NeighborhoodReady{},FullDetailReady{},WholeViewReady{};
@@ -6940,6 +6944,17 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                 {
                     ++FullDetailFinished;
                     FullDetailReady=std::max(FullDetailReady,Tile.CompletedAt);
+                    NativeSolidBoxes+=Tile.CoreDiagnostics.solidBoxes;
+                    NativeAirBoxes+=Tile.CoreDiagnostics.airBoxes;
+                    NativeMixedBoxes+=Tile.CoreDiagnostics.mixedBoxes;
+                    NativeUnknownBoxes+=Tile.CoreDiagnostics.unknownBoxes;
+                    NativeFieldCalls+=Tile.CoreDiagnostics.fieldCalls;
+                    NativeColumnHits+=Tile.CoreDiagnostics.columnCacheHits;
+                    NativeColumnMisses+=Tile.CoreDiagnostics.columnCacheMisses;
+                    NativeMeshingSkips+=Tile.CoreDiagnostics.meshingSkipped?1u:0u;
+                    NativeClassificationMilliseconds+=Tile.CoreDiagnostics.classificationMilliseconds;
+                    NativeColumnComputeMilliseconds+=Tile.CoreDiagnostics.columnComputeMilliseconds;
+                    NativeMeshingMilliseconds+=Tile.CoreDiagnostics.meshingMilliseconds;
                 }
                 if(bHashDensity)
                 {
@@ -6973,6 +6988,17 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
             WorkerCount,ShapeSeconds,NeighborhoodMeshSeconds,NeighborhoodSeconds,
             FullDetailSeconds,WholeViewSeconds,NeighborhoodFinished,
             FullDetailFinished,FullDetailExpected,Finished,Desired.Tiles.size(),StreamSeconds);
+        std::printf("[WorldAssemblerTilePipeline] full_detail_tiles=%d solid_boxes=%llu air_boxes=%llu mixed_boxes=%llu unknown_boxes=%llu whole_tile_skips=%llu field_calls=%llu column_cache_hits=%llu column_cache_misses=%llu column_compute_worker_ms=%.3f classification_worker_ms=%.3f meshing_worker_ms=%.3f\n",
+            FullDetailExpected,static_cast<unsigned long long>(NativeSolidBoxes),
+            static_cast<unsigned long long>(NativeAirBoxes),
+            static_cast<unsigned long long>(NativeMixedBoxes),
+            static_cast<unsigned long long>(NativeUnknownBoxes),
+            static_cast<unsigned long long>(NativeMeshingSkips),
+            static_cast<unsigned long long>(NativeFieldCalls),
+            static_cast<unsigned long long>(NativeColumnHits),
+            static_cast<unsigned long long>(NativeColumnMisses),
+            NativeColumnComputeMilliseconds,NativeClassificationMilliseconds,
+            NativeMeshingMilliseconds);
 
         bool bHashesPassing=true;
         if(bHashDensity)
@@ -7066,6 +7092,25 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
         auto PlayerNeighborhoodCompleted=std::chrono::steady_clock::time_point{};
         std::vector<FStandaloneCpuTile> CacheTiles;
         if(!BakeCachePath.empty())CacheTiles.reserve(Desired.Tiles.size());
+        uint64 NativeSolidBoxes=0,NativeAirBoxes=0,NativeMixedBoxes=0,NativeUnknownBoxes=0;
+        uint64 NativeFieldCalls=0,NativeColumnHits=0,NativeColumnMisses=0,NativeMeshingSkips=0;
+        uint64 NativeFloatFieldCalls=0,NativeLatticeFieldCalls=0,NativeUnclampedFieldCalls=0;
+        double NativeClassificationMilliseconds=0.0,NativeColumnComputeMilliseconds=0.0;
+        double NativeMeshingMilliseconds=0.0;
+        uint64 WholeSolidBoxes=0,WholeAirBoxes=0,WholeMixedBoxes=0,WholeUnknownBoxes=0;
+        uint64 WholeFieldCalls=0,WholeColumnHits=0,WholeColumnMisses=0,WholeTileSkips=0;
+        uint64 WholeFloatFieldCalls=0,WholeLatticeFieldCalls=0,WholeUnclampedFieldCalls=0;
+        double WholeClassificationMilliseconds=0.0,WholeColumnComputeMilliseconds=0.0;
+        double WholeMeshingMilliseconds=0.0;
+        uint64 WholeSolidBoxesByLevel[MaxLevels+1]{},WholeAirBoxesByLevel[MaxLevels+1]{};
+        uint64 WholeMixedBoxesByLevel[MaxLevels+1]{},WholeUnknownBoxesByLevel[MaxLevels+1]{};
+        uint64 WholeFieldCallsByLevel[MaxLevels+1]{},WholeColumnHitsByLevel[MaxLevels+1]{};
+        uint64 WholeFloatFieldCallsByLevel[MaxLevels+1]{},WholeLatticeFieldCallsByLevel[MaxLevels+1]{};
+        uint64 WholeUnclampedFieldCallsByLevel[MaxLevels+1]{};
+        uint64 WholeColumnMissesByLevel[MaxLevels+1]{},WholeTileSkipsByLevel[MaxLevels+1]{};
+        double WholeClassificationMillisecondsByLevel[MaxLevels+1]{};
+        double WholeColumnComputeMillisecondsByLevel[MaxLevels+1]{};
+        double WholeMeshingMillisecondsByLevel[MaxLevels+1]{};
         if(CoreWorld&&!FarAudit)
         {
             // Tile keys and band limits are already captured in Desired. Core owns field and
@@ -7115,6 +7160,43 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                 if(FarAudit)FarAudit->AuditTile(Tile);
                 ++Finished;
                 const int32 Level=Tile.Key.Level;
+                if(CoreWorld)
+                {
+                    WholeSolidBoxes+=Tile.CoreDiagnostics.solidBoxes;
+                    WholeAirBoxes+=Tile.CoreDiagnostics.airBoxes;
+                    WholeMixedBoxes+=Tile.CoreDiagnostics.mixedBoxes;
+                    WholeUnknownBoxes+=Tile.CoreDiagnostics.unknownBoxes;
+                    WholeFieldCalls+=Tile.CoreDiagnostics.fieldCalls;
+                    WholeFloatFieldCalls+=Tile.CoreDiagnostics.floatFieldCalls;
+                    WholeLatticeFieldCalls+=Tile.CoreDiagnostics.latticeFieldCalls;
+                    WholeUnclampedFieldCalls+=Tile.CoreDiagnostics.unclampedFieldCalls;
+                    WholeColumnHits+=Tile.CoreDiagnostics.columnCacheHits;
+                    WholeColumnMisses+=Tile.CoreDiagnostics.columnCacheMisses;
+                    WholeTileSkips+=Tile.CoreDiagnostics.meshingSkipped?1u:0u;
+                    WholeClassificationMilliseconds+=Tile.CoreDiagnostics.classificationMilliseconds;
+                    WholeColumnComputeMilliseconds+=Tile.CoreDiagnostics.columnComputeMilliseconds;
+                    WholeMeshingMilliseconds+=Tile.CoreDiagnostics.meshingMilliseconds;
+                    if(Level>=0&&Level<=MaxLevels)
+                    {
+                        WholeSolidBoxesByLevel[Level]+=Tile.CoreDiagnostics.solidBoxes;
+                        WholeAirBoxesByLevel[Level]+=Tile.CoreDiagnostics.airBoxes;
+                        WholeMixedBoxesByLevel[Level]+=Tile.CoreDiagnostics.mixedBoxes;
+                        WholeUnknownBoxesByLevel[Level]+=Tile.CoreDiagnostics.unknownBoxes;
+                        WholeFieldCallsByLevel[Level]+=Tile.CoreDiagnostics.fieldCalls;
+                        WholeFloatFieldCallsByLevel[Level]+=Tile.CoreDiagnostics.floatFieldCalls;
+                        WholeLatticeFieldCallsByLevel[Level]+=Tile.CoreDiagnostics.latticeFieldCalls;
+                        WholeUnclampedFieldCallsByLevel[Level]+=Tile.CoreDiagnostics.unclampedFieldCalls;
+                        WholeColumnHitsByLevel[Level]+=Tile.CoreDiagnostics.columnCacheHits;
+                        WholeColumnMissesByLevel[Level]+=Tile.CoreDiagnostics.columnCacheMisses;
+                        WholeTileSkipsByLevel[Level]+=Tile.CoreDiagnostics.meshingSkipped?1u:0u;
+                        WholeClassificationMillisecondsByLevel[Level]
+                            +=Tile.CoreDiagnostics.classificationMilliseconds;
+                        WholeColumnComputeMillisecondsByLevel[Level]
+                            +=Tile.CoreDiagnostics.columnComputeMilliseconds;
+                        WholeMeshingMillisecondsByLevel[Level]
+                            +=Tile.CoreDiagnostics.meshingMilliseconds;
+                    }
+                }
                 if(PlayerNeighborhoodTiles.contains(Tile.Key))
                 {
                     PlayerNeighborhoodReady.insert(Tile.Key);
@@ -7140,7 +7222,24 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                     if(Tile.bHasPayloadHash)PayloadHashRows[Level].push_back({Tile.Key,Tile.PayloadHash});
                     if(Tile.bHasTopologyHash)TopologyHashRows[Level].push_back({Tile.Key,Tile.TopologyHash});
                 }
-                if(Level<World.FullResClipLevels)++FullDetailFinished;
+                if(Level<World.FullResClipLevels)
+                {
+                    ++FullDetailFinished;
+                    NativeSolidBoxes+=Tile.CoreDiagnostics.solidBoxes;
+                    NativeAirBoxes+=Tile.CoreDiagnostics.airBoxes;
+                    NativeMixedBoxes+=Tile.CoreDiagnostics.mixedBoxes;
+                    NativeUnknownBoxes+=Tile.CoreDiagnostics.unknownBoxes;
+                    NativeFieldCalls+=Tile.CoreDiagnostics.fieldCalls;
+                    NativeFloatFieldCalls+=Tile.CoreDiagnostics.floatFieldCalls;
+                    NativeLatticeFieldCalls+=Tile.CoreDiagnostics.latticeFieldCalls;
+                    NativeUnclampedFieldCalls+=Tile.CoreDiagnostics.unclampedFieldCalls;
+                    NativeColumnHits+=Tile.CoreDiagnostics.columnCacheHits;
+                    NativeColumnMisses+=Tile.CoreDiagnostics.columnCacheMisses;
+                    NativeMeshingSkips+=Tile.CoreDiagnostics.meshingSkipped?1u:0u;
+                    NativeClassificationMilliseconds+=Tile.CoreDiagnostics.classificationMilliseconds;
+                    NativeColumnComputeMilliseconds+=Tile.CoreDiagnostics.columnComputeMilliseconds;
+                    NativeMeshingMilliseconds+=Tile.CoreDiagnostics.meshingMilliseconds;
+                }
                 if(bShardAudit&&Level==0)
                 {
                     const FMeshSheetAudit TileAudit=AuditThinMeshSheets(Tile,CameraPositionVoxels,
@@ -7265,6 +7364,21 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                 else
                     std::printf("[StreamFullDetail] wall=%.3fs generated=%d/%d resident_tiles_cpu_only=1 hash=off\n",
                         FullDetailSeconds,FullDetailFinished,FullDetailExpected);
+                if(CoreWorld)
+                    std::printf("[WorldAssemblerTilePipeline] full_detail_tiles=%d solid_boxes=%llu air_boxes=%llu mixed_boxes=%llu unknown_boxes=%llu whole_tile_skips=%llu field_calls=%llu float_field_calls=%llu lattice_field_calls=%llu unclamped_field_calls=%llu column_cache_hits=%llu column_cache_misses=%llu column_compute_worker_ms=%.3f classification_worker_ms=%.3f meshing_worker_ms=%.3f\n",
+                        FullDetailExpected,static_cast<unsigned long long>(NativeSolidBoxes),
+                        static_cast<unsigned long long>(NativeAirBoxes),
+                        static_cast<unsigned long long>(NativeMixedBoxes),
+                        static_cast<unsigned long long>(NativeUnknownBoxes),
+                        static_cast<unsigned long long>(NativeMeshingSkips),
+                        static_cast<unsigned long long>(NativeFieldCalls),
+                        static_cast<unsigned long long>(NativeFloatFieldCalls),
+                        static_cast<unsigned long long>(NativeLatticeFieldCalls),
+                        static_cast<unsigned long long>(NativeUnclampedFieldCalls),
+                        static_cast<unsigned long long>(NativeColumnHits),
+                        static_cast<unsigned long long>(NativeColumnMisses),
+                        NativeColumnComputeMilliseconds,NativeClassificationMilliseconds,
+                        NativeMeshingMilliseconds);
                 std::fflush(stdout);
             }
         }
@@ -7312,6 +7426,40 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                 std::max(0.0,100.0-WorkerBusyPercent),
                 static_cast<double>(TotalMeshPayloadAllocatedBytes)/1048576.0,
                 static_cast<double>(TotalViewerOutputBytes)/1048576.0,DesiredTotal);
+        if(CoreWorld)
+            std::printf("[WorldAssemblerWholeViewPipeline] tiles=%d solid_boxes=%llu air_boxes=%llu mixed_boxes=%llu unknown_boxes=%llu whole_tile_skips=%llu field_calls=%llu float_field_calls=%llu lattice_field_calls=%llu unclamped_field_calls=%llu column_cache_hits=%llu column_cache_misses=%llu column_compute_worker_ms=%.3f classification_worker_ms=%.3f meshing_worker_ms=%.3f\n",
+                DesiredTotal,static_cast<unsigned long long>(WholeSolidBoxes),
+                static_cast<unsigned long long>(WholeAirBoxes),
+                static_cast<unsigned long long>(WholeMixedBoxes),
+                static_cast<unsigned long long>(WholeUnknownBoxes),
+                static_cast<unsigned long long>(WholeTileSkips),
+                static_cast<unsigned long long>(WholeFieldCalls),
+                static_cast<unsigned long long>(WholeFloatFieldCalls),
+                static_cast<unsigned long long>(WholeLatticeFieldCalls),
+                static_cast<unsigned long long>(WholeUnclampedFieldCalls),
+                static_cast<unsigned long long>(WholeColumnHits),
+                static_cast<unsigned long long>(WholeColumnMisses),
+                WholeColumnComputeMilliseconds,WholeClassificationMilliseconds,
+                WholeMeshingMilliseconds);
+        if(CoreWorld)
+            for(int32 Level=0;Level<=MaxLevels;++Level)
+                if(TilesByLevel[Level]>0)
+                    std::printf("[WorldAssemblerLODProfile] lod=%d tiles=%llu solid_boxes=%llu air_boxes=%llu mixed_boxes=%llu unknown_boxes=%llu whole_tile_skips=%llu field_calls=%llu float_field_calls=%llu lattice_field_calls=%llu unclamped_field_calls=%llu column_hits=%llu column_misses=%llu column_compute_worker_ms=%.3f classification_worker_ms=%.3f meshing_worker_ms=%.3f\n",
+                        Level,static_cast<unsigned long long>(TilesByLevel[Level]),
+                        static_cast<unsigned long long>(WholeSolidBoxesByLevel[Level]),
+                        static_cast<unsigned long long>(WholeAirBoxesByLevel[Level]),
+                        static_cast<unsigned long long>(WholeMixedBoxesByLevel[Level]),
+                        static_cast<unsigned long long>(WholeUnknownBoxesByLevel[Level]),
+                        static_cast<unsigned long long>(WholeTileSkipsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeFieldCallsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeFloatFieldCallsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeLatticeFieldCallsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeUnclampedFieldCallsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeColumnHitsByLevel[Level]),
+                        static_cast<unsigned long long>(WholeColumnMissesByLevel[Level]),
+                        WholeColumnComputeMillisecondsByLevel[Level],
+                        WholeClassificationMillisecondsByLevel[Level],
+                        WholeMeshingMillisecondsByLevel[Level]);
         std::printf("[StreamCacheUse] hits=%llu requested=%d\n",
             static_cast<unsigned long long>(Streamer.GetCacheHits()),DesiredTotal);
         if(bShardAudit)
@@ -7883,16 +8031,39 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
             {
                 VoxelForgeCore::WorldAssemblyFeatureV1 shelf;
                 shelf.stableId=WorldAssemblyFeatureId(recipe.seed,cliffX,cliffY,0x4f564552u);
-                shelf.type=2;
-                const int reach=72,width=36;
-                const int minX=xAxis?cliffX+(downhill<0?-reach:0)-4:cliffX-width;
-                const int maxX=xAxis?cliffX+(downhill>0?reach:0)+4:cliffX+width;
-                const int minY=xAxis?cliffY-width:cliffY+(downhill<0?-reach:0)-4;
-                const int maxY=xAxis?cliffY+width:cliffY+(downhill>0?reach:0)+4;
+                shelf.type=4;
+                constexpr int reach=72,width=36,height=64,feather=8;
+                const int dirX=xAxis?downhill:0,dirY=xAxis?0:downhill;
+                const int minX=xAxis?(dirX>0?cliffX-feather:cliffX-reach-feather)
+                    :cliffX-width-feather;
+                const int maxX=xAxis?(dirX>0?cliffX+reach+feather:cliffX+feather)
+                    :cliffX+width+feather;
+                const int minY=xAxis?cliffY-width-feather
+                    :(dirY>0?cliffY-feather:cliffY-reach-feather);
+                const int maxY=xAxis?cliffY+width+feather
+                    :(dirY>0?cliffY+reach+feather:cliffY+feather);
+                VoxelForgeCore::Heightfield2D baseField(recipe,stratum);
+                double lowestGround=std::numeric_limits<double>::infinity();
+                double highestGround=-std::numeric_limits<double>::infinity();
+                for(int sampleY=minY;sampleY<=maxY;sampleY+=4)
+                for(int sampleX=minX;sampleX<=maxX;sampleX+=4)
+                {
+                    const auto sample=baseField.point(WorldAssemblyFixed(sampleX),
+                        WorldAssemblyFixed(sampleY),0);
+                    const double heightQ=static_cast<double>(sample.groundHeightSubvoxels)
+                        /VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                    lowestGround=std::min(lowestGround,heightQ);
+                    highestGround=std::max(highestGround,heightQ);
+                }
+                if(!std::isfinite(lowestGround)||!std::isfinite(highestGround))
+                {error="world assembler cliff shelf could not bound its terrain columns";return false;}
                 shelf.minimumSubvoxels={WorldAssemblyFixed(minX),WorldAssemblyFixed(minY),
-                    WorldAssemblyFixed(std::max<double>(bottomVoxel,ground-12.0))};
+                    WorldAssemblyFixed(std::max<double>(bottomVoxel,lowestGround-4.0))};
                 shelf.maximumSubvoxels={WorldAssemblyFixed(maxX),WorldAssemblyFixed(maxY),
-                    WorldAssemblyFixed(std::min<double>((topChunkZ+1)*CHUNK_SIZE,ground+5.0))};
+                    WorldAssemblyFixed(std::min<double>((topChunkZ+1)*CHUNK_SIZE,
+                        highestGround+height+4.0))};
+                shelf.parametersSubvoxels={WorldAssemblyFixed(dirX),WorldAssemblyFixed(dirY),
+                    WorldAssemblyFixed(height),WorldAssemblyFixed(reach)};
                 stratum.features.push_back(shelf);
             }
         }
@@ -7963,6 +8134,101 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
             static_cast<unsigned long long>(bounds.exceptionPointSamples),
             bounds.negativeControlDetected?"true":"false",bounds.passed?"PASS":"FAIL");
 
+        bool cliffRegressionPassing=false;
+        const auto cliffIt=std::find_if(plan.features.begin(),plan.features.end(),
+            [](const auto& feature){return feature.type==4;});
+        if(cliffIt!=plan.features.end())
+        {
+            const std::size_t cliffIndex=static_cast<std::size_t>(cliffIt-plan.features.begin());
+            auto basePlan=plan;basePlan.features.erase(basePlan.features.begin()+cliffIndex);
+            auto boxControlPlan=plan;boxControlPlan.features[cliffIndex].type=2;
+            const VoxelForgeCore::Heightfield2D baseBlock(manifest->recipe,basePlan);
+            const VoxelForgeCore::Heightfield2D boxControlBlock(manifest->recipe,boxControlPlan);
+            const auto& feature=*cliffIt;
+            const std::int64_t cx=(feature.minimumSubvoxels[0]+feature.maximumSubvoxels[0])/2;
+            const std::int64_t cy=(feature.minimumSubvoxels[1]+feature.maximumSubvoxels[1])/2;
+            const std::int64_t z=feature.maximumSubvoxels[2]
+                -VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+            std::uint64_t airSamples=0,controlSlabSamples=0,taperedTopSamples=0;
+            for(int gy=-2;gy<=2;++gy)
+            for(int gx=-2;gx<=2;++gx)
+            {
+                const std::int64_t x=cx+gx*8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                const std::int64_t y=cy+gy*8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                const auto base=baseBlock.point(x,y,z);
+                const auto control=boxControlBlock.point(x,y,z);
+                const auto tapered=block.point(x,y,z);
+                if(base.densitySubvoxels>0)
+                {
+                    ++airSamples;
+                    if(control.densitySubvoxels<0)++controlSlabSamples;
+                    if(tapered.densitySubvoxels<0)++taperedTopSamples;
+                }
+            }
+            const bool negativeControl=airSamples>=8&&controlSlabSamples==airSamples;
+            cliffRegressionPassing=negativeControl&&taperedTopSamples*2<airSamples;
+            std::printf("[WorldAssemblerCliffShapeAudit] top_plane_q=%lld baseline_air_samples=%llu old_type2_blocked=%llu tapered_type4_blocked=%llu negative_control_detected=%s status=%s\n",
+                static_cast<long long>(z),static_cast<unsigned long long>(airSamples),
+                static_cast<unsigned long long>(controlSlabSamples),
+                static_cast<unsigned long long>(taperedTopSamples),
+                negativeControl?"true":"false",cliffRegressionPassing?"PASS":"FAIL");
+        }
+        else std::printf("[WorldAssemblerCliffShapeAudit] type4_shelf=missing status=FAIL\n");
+
+        std::uint64_t seamBoxes=0,seamLatticeSamples=0,seamClassificationFailures=0;
+        for(int boundaryY=-64;boundaryY<=64;boundaryY+=32)
+        for(int boundaryX=-64;boundaryX<=64;boundaryX+=32)
+        {
+            const std::int64_t minX=static_cast<std::int64_t>(boundaryX-8)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+            const std::int64_t maxX=static_cast<std::int64_t>(boundaryX+8)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+            const std::int64_t minY=static_cast<std::int64_t>(boundaryY-8)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+            const std::int64_t maxY=static_cast<std::int64_t>(boundaryY+8)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+            std::int64_t groundMin=std::numeric_limits<std::int64_t>::max();
+            std::int64_t groundMax=std::numeric_limits<std::int64_t>::min();
+            std::int64_t capMin=std::numeric_limits<std::int64_t>::max();
+            for(std::int64_t y=minY;y<=maxY;y+=8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel)
+            for(std::int64_t x=minX;x<=maxX;x+=8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel)
+            {
+                const auto column=block.point(x,y,0);
+                groundMin=std::min(groundMin,column.groundHeightSubvoxels);
+                groundMax=std::max(groundMax,column.groundHeightSubvoxels);
+                capMin=std::min(capMin,column.capHeightSubvoxels);
+            }
+            for(const bool bAir:{true,false})
+            {
+                const std::int64_t minZ=bAir?groundMax+16*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel
+                    :groundMin-24*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                const std::int64_t maxZ=bAir?minZ+8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel
+                    :minZ+8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+                if(bAir&&maxZ>=capMin)continue;
+                const auto verdict=block.classifyLatticeBox(minX,minY,minZ,maxX,maxY,maxZ,8);
+                const auto expected=bAir?VoxelForgeCore::HeightfieldBoxClass::allAir
+                    :VoxelForgeCore::HeightfieldBoxClass::allSolid;
+                ++seamBoxes;
+                if(verdict!=expected){++seamClassificationFailures;continue;}
+                for(std::int64_t zq=minZ;zq<=maxZ;zq+=8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel)
+                for(std::int64_t y=minY;y<=maxY;y+=8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel)
+                for(std::int64_t x=minX;x<=maxX;x+=8*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel)
+                {
+                    const auto sample=block.point(x,y,zq);
+                    if((bAir&&sample.densitySubvoxels<=0)||(!bAir&&sample.densitySubvoxels>=0))
+                        ++seamClassificationFailures;
+                    ++seamLatticeSamples;
+                }
+            }
+        }
+        const bool seamClassificationPassing=seamBoxes>0&&seamClassificationFailures==0
+            &&seamLatticeSamples>0;
+        std::printf("[WorldAssemblerTileSeamAudit] boxes=%llu lattice_samples=%llu false_classifications=%llu seam_spacing_vox=32 box_span_vox=16 status=%s\n",
+            static_cast<unsigned long long>(seamBoxes),
+            static_cast<unsigned long long>(seamLatticeSamples),
+            static_cast<unsigned long long>(seamClassificationFailures),
+            seamClassificationPassing?"PASS":"FAIL");
+
         struct Query {std::int64_t x=0,y=0,z=0;};
         constexpr int side=64;
         std::vector<Query> queries;
@@ -8148,7 +8414,7 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                     /VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel,0.0,true});
         printCaptureSite("biome_border",borderSite);
         printCaptureSite("coast",coastSite);
-        if(!plan.features.empty()&&plan.features.front().type==2)
+        if(!plan.features.empty()&&(plan.features.front().type==2||plan.features.front().type==4))
         {
             const auto& feature=plan.features.front();
             const double fx=(feature.minimumSubvoxels[0]+feature.maximumSubvoxels[0])
@@ -8316,7 +8582,8 @@ float3 Lit=Rock*(Ambient+0.88*Diffuse)+float3(0.50,0.69,0.82)*Head*0.75;
                 ownerSaved&&nativeSaved?"PASS":"FAIL");
         }
         std::printf("[WorldAssemblerFullViewTiming] status=NOT_MEASURED_IN_AUDIT_MODE; capture_viewer_runs_report_separately\n");
-        return bounds.passed&&deterministic&&coreQueryPass?0:11;
+        return bounds.passed&&cliffRegressionPassing&&seamClassificationPassing
+            &&deterministic&&coreQueryPass?0:11;
     }
 }
 
@@ -8683,10 +8950,18 @@ int main(int Argc,char** Argv)
         std::printf("Standalone max clip level override: exported=%d -> max_level=%d.\n",
             ExportMaxClipLevel,MaxClipLevelOverride);
     }
-    if(App.bWorldAssemblerPrototype
-        &&!AttachRound1WorldAssemblyPrototype(*App.World,App.OwnerJsonRoot,Error,
-            WorldAssemblyManifestOutputPath))
-    {std::fprintf(stderr,"World assembler prototype setup failed: %s\n",Error.c_str());return 2;}
+    if(App.bWorldAssemblerPrototype)
+    {
+        const auto PlanStart=std::chrono::steady_clock::now();
+        const bool bPlanReady=AttachRound1WorldAssemblyPrototype(*App.World,App.OwnerJsonRoot,
+            Error,WorldAssemblyManifestOutputPath);
+        const double PlanMilliseconds=std::chrono::duration<double,std::milli>(
+            std::chrono::steady_clock::now()-PlanStart).count();
+        std::printf("[WorldAssemblerPlanTiming] total_ms=%.3f status=%s\n",
+            PlanMilliseconds,bPlanReady?"PASS":"FAIL");
+        if(!bPlanReady)
+        {std::fprintf(stderr,"World assembler prototype setup failed: %s\n",Error.c_str());return 2;}
+    }
     if(App.bWorldAssemblerAuditOnly)
     {
         App.Snapshot=VoxelForgeCore::MakeStandaloneSnapshotFromParsedJson(App.OwnerJsonRoot,