wip(assembler): round L11 -- fix 24 m+ crossing crash; near ring ready 2x sooner at spawn

Crash: crossing tiles were coalesced into one huge rectangle, and BuildSpatialBins tried to
resize to ~4.3e17 bytes (std::bad_alloc; the L7 32 m failure had the same cause). Analytic
regions now skip unread dense bins and compile in world-aligned 128-voxel pages, published
together; out-of-range keys error before allocation. 24 m, 32 m and 1 km crossings pass
(1 km: 72 pages, peak RSS 700 MiB).
Spawn: World::isTileShapeFree proves LOD0 SurfaceWorld tiles that never read the cave shape;
those start before shape compile, and all others wait. Reviewer W12 no-hash: near ring 0.337 ->
0.159 s, whole view +2.1%. All SurfaceWorld/FloatingIslands hashes unchanged (W1/W8/W12, both
compilers, forced-overlap run). Unreal VoxelWorld.cpp adapter changed but NOT built here.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

Standalone/Core/src/ShapeWorldInternal.h

@@ -487,7 +487,13 @@ public:
         const auto Stage=Clock::now();
         BuildLayerBounds();BuildOwnerPrimitives();
         if(RoundTunnelsEnabled)BuildRoundTunnelPrimitives();
-        BuildSpatialBins(LineBinSize);
+        // Analytic regions never build packed interval lines. Their exact-density fallback only
+        // reads the sparse 3D primitive bins; allocating the dense per-axis line-bin grids here
+        // scales with the region's XY bounding rectangle and is both unnecessary and unbounded.
+        // Les regions analytiques n'utilisent pas les intervalles compactes; leur repli exact lit
+        // les bins 3D clairsemes. Les grilles denses par axe croitraient avec la surface XY sans
+        // servir ce chemin.
+        BuildSpatialBins(LineBinSize,false);
         Stats.ShapeSeconds=std::chrono::duration<double>(Clock::now()-Stage).count();
         Stats.PrimitiveCount=Primitives.size();
         if(Primitives.empty())
@@ -497,6 +503,59 @@ public:
         return true;
     }
 
+    void InitializeNativeSurfaceOnly(FStandaloneOwnerWorld& World,
+        const VoxelForgeCore::WorldAssemblyManifest* InWorldAssembly,
+        const FIntVector& InMinimum,const FIntVector& InMaximum)
+    {
+        Owner=&World;WorldAssembly=InWorldAssembly;
+        NativeOnlyMinimum=InMinimum;NativeOnlyMaximum=InMaximum;
+        bNativeOnly=true;bAnalyticOnly=true;Built=true;
+        NativeOnlyViolations.store(0,std::memory_order_relaxed);
+    }
+
+    bool BuildShapeDependencyProof(FStandaloneOwnerWorld& World,
+        const FIntVector& MinVoxels,const FIntVector& MaxVoxels,bool bInRoundTunnels)
+    {
+        Owner=&World;WorkerCount=1;RoundTunnelsEnabled=bInRoundTunnels;
+        bAnalyticOnly=true;bNativeOnly=false;Stats={};
+        for(int32 Axis=0;Axis<3;++Axis)
+        {
+            Min[Axis]=(&MinVoxels.X)[Axis]-2;Max[Axis]=(&MaxVoxels.X)[Axis]+2;
+            ClipMin[Axis]=(&MinVoxels.X)[Axis];ClipMax[Axis]=(&MaxVoxels.X)[Axis];
+            Size[Axis]=Max[Axis]-Min[Axis]+1;
+            if(Size[Axis]<=0||Size[Axis]>4096||ClipMax[Axis]<ClipMin[Axis])return false;
+        }
+        BuildLayerBounds();BuildOwnerPrimitives();
+        if(RoundTunnelsEnabled)BuildRoundTunnelPrimitives();
+        return true;
+    }
+
+    bool HasShapeDependencyInBox(const FIntVector& Origin,int32 Step,int32 Cells) const
+    {
+        const int32 Pad=std::max(Step,1);
+        const int32 BMin[3]={Origin.X-Pad,Origin.Y-Pad,Origin.Z-Pad};
+        const int32 BMax[3]={Origin.X+(Cells+1)*Step,Origin.Y+(Cells+1)*Step,
+            Origin.Z+(Cells+1)*Step};
+        for(const FPrimitive& Primitive:Primitives)
+        {
+            bool bOverlaps=true;
+            for(int32 Axis=0;Axis<3;++Axis)
+                bOverlaps=bOverlaps&&Primitive.Max[Axis]+DetailBand>=BMin[Axis]
+                    &&Primitive.Min[Axis]-DetailBand<=BMax[Axis];
+            if(bOverlaps)return true;
+        }
+        for(const FInterval& Range:LayerRanges)
+            if(Range.Lo<=BMax[2]&&Range.Hi>=BMin[2]
+                &&(Range.Lo>=BMin[2]||Range.Hi<=BMax[2]))return true;
+        return false;
+    }
+
+    bool IsNativeOnly() const { return bNativeOnly; }
+    uint32 GetNativeOnlyViolationCount() const
+    { return NativeOnlyViolations.load(std::memory_order_relaxed); }
+    void RecordNativeOnlyViolation() const
+    { NativeOnlyViolations.fetch_add(1,std::memory_order_relaxed); }
+
     const FBuildStats& GetStats() const { return Stats; }
     bool IsBuilt() const { return Built; }
     bool HasFarWorld() const { return FarBuilt; }
@@ -951,6 +1010,15 @@ public:
     // edge interpolation and normals to the existing mesher.
     float DensityAt(float X,float Y,float Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(X,Y,Z))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(X,Y,Z,NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(X,Y,Z,IslandDensity))
         {
@@ -975,6 +1043,17 @@ public:
 
     float DensityAtLattice(int32 X,int32 Y,int32 Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(static_cast<float>(X),static_cast<float>(Y),
+                static_cast<float>(Z)))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(static_cast<float>(X),static_cast<float>(Y),
+                static_cast<float>(Z),NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(static_cast<float>(X),static_cast<float>(Y),
             static_cast<float>(Z),IslandDensity))
@@ -1003,6 +1082,15 @@ public:
 
     float DensityAtUnclamped(float X,float Y,float Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(X,Y,Z))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(X,Y,Z,NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(X,Y,Z,IslandDensity))
         {
@@ -1023,6 +1111,8 @@ public:
     VoxelForgeCore::DetailFieldSample DetailSampleAt(float X,float Y,float Z) const
     {
         VoxelForgeCore::DetailFieldSample Sample;
+        if(bNativeOnly)
+        {RecordNativeOnlyViolation();return Sample;}
         AnalyticDensityAt(X,Y,Z,false,&Sample.displacement,
             &Sample.caveInfluence,&Sample.floorInfluence);
         return Sample;
@@ -1040,6 +1130,12 @@ public:
     {
         Count=std::clamp(Count,0,8);
         if(Count==0)return;
+        if(bNativeOnly)
+        {
+            for(int32 Lane=0;Lane<Count;++Lane)
+                OutDensity[Lane]=DensityAtLattice(XStart+Lane*XStep,Y,Z);
+            return;
+        }
         bool bHasLegacySurfaceSample=false;
         bool bHasNativeIslandSample=false;
         for(int32 Lane=0;Lane<Count;++Lane)
@@ -1202,10 +1298,17 @@ public:
     {
         if(!WorldAssembly||!Owner||!Owner->Manager||!Owner->Generator
             ||!std::isfinite(X)||!std::isfinite(Y))return false;
+        const std::int64_t chunkMinimum=static_cast<std::int64_t>(ChunkZ)*CHUNK_SIZE;
+        const std::int64_t chunkMaximum=chunkMinimum+CHUNK_SIZE;
+        if(bNativeOnly&&(!NativeOnlyContainsColumn(X,Y)
+            ||chunkMaximum<NativeOnlyMinimum.Z||chunkMinimum>NativeOnlyMaximum.Z
+            ||Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
+                !=ECaveGeneratorType::SurfaceWorld))
+        {RecordNativeOnlyViolation();return false;}
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::SurfaceWorld)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -1250,6 +1353,17 @@ public:
                 !=ECaveGeneratorType::SurfaceWorld)return false;
             Plan=Candidate;
         }
+        if(bNativeOnly)
+        {
+            const int32 BMinX=Origin.X-Pad,BMinY=Origin.Y-Pad;
+            const int32 BMaxX=Origin.X+(Cells+1)*Step;
+            const int32 BMaxY=Origin.Y+(Cells+1)*Step;
+            if(BMinX<NativeOnlyMinimum.X||BMinY<NativeOnlyMinimum.Y
+                ||BMin<NativeOnlyMinimum.Z||BMaxX>NativeOnlyMaximum.X
+                ||BMaxY>NativeOnlyMaximum.Y||BMax>NativeOnlyMaximum.Z)
+            {RecordNativeOnlyViolation();return false;}
+        }
+        if(bNativeOnly&&!Plan)RecordNativeOnlyViolation();
         return Plan!=nullptr;
     }
 
@@ -1281,7 +1395,7 @@ public:
                 {
                     bSurfaceOverlap=true;
                     const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-                        static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+                        static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
                     const auto* Candidate=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
                     if(!Candidate||(SurfacePlan&&SurfacePlan!=Candidate))
                         bBadPlan=true;
@@ -1306,7 +1420,7 @@ public:
                 {
                     bIslandOverlap=true;
                     const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-                        static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+                        static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
                     const auto* Candidate=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
                     if(!Candidate||(IslandPlan&&IslandPlan!=Candidate))bBadPlan=true;
                     IslandPlan=Candidate;
@@ -1327,6 +1441,19 @@ public:
             else ++Counts.MixedBoxes;
             return Result;
         };
+        if(bNativeOnly)
+        {
+            const bool bInsideProofBox=BMin[0]>=NativeOnlyMinimum.X
+                &&BMin[1]>=NativeOnlyMinimum.Y&&BMin[2]>=NativeOnlyMinimum.Z
+                &&BMax[0]<=NativeOnlyMaximum.X&&BMax[1]<=NativeOnlyMaximum.Y
+                &&BMax[2]<=NativeOnlyMaximum.Z;
+            if(!bInsideProofBox||!bSurfaceOverlap||bIslandOverlap||bOtherStrateOverlap
+                ||bBadPlan||!EditBrushes.empty())
+            {
+                RecordNativeOnlyViolation();
+                return Finish(EVoxelTileClass::Mixed,true);
+            }
+        }
         // A box crossing recipes cannot use one field interval; unknown composition stays Mixed.
         // Une boite qui traverse plusieurs recettes reste Mixed, car l'intervalle d'un seul champ ne suffit pas.
         if(bBadPlan||(bSurfaceOverlap&&(bIslandOverlap||bOtherStrateOverlap))
@@ -1341,7 +1468,7 @@ public:
         // for SurfaceWorld and FloatingIslands. Legacy analytic primitives/layer bounds cannot
         // modify that field; only the explicit edit transaction above can. Keep their guards on
         // the legacy classifier path, where those overlays do participate in density.
-        if(!bUseNativeLatticeProof||(!bSurfaceOverlap&&!bIslandOverlap))
+        if(!bNativeOnly&&(!bUseNativeLatticeProof||(!bSurfaceOverlap&&!bIslandOverlap)))
         {
             for(int32 BZ=FloorDiv(BMin[2],ActiveSpatialBinSize);BZ<=FloorDiv(BMax[2],ActiveSpatialBinSize);++BZ)
             for(int32 BY=FloorDiv(BMin[1],ActiveSpatialBinSize);BY<=FloorDiv(BMax[1],ActiveSpatialBinSize);++BY)
@@ -1880,6 +2007,21 @@ public:
     }
 
 private:
+    bool NativeOnlyContainsColumn(float X,float Y) const
+    {
+        return std::isfinite(X)&&std::isfinite(Y)
+            &&X>=NativeOnlyMinimum.X&&X<=NativeOnlyMaximum.X
+            &&Y>=NativeOnlyMinimum.Y&&Y<=NativeOnlyMaximum.Y;
+    }
+
+    bool NativeOnlyContains(float X,float Y,float Z) const
+    {
+        return std::isfinite(X)&&std::isfinite(Y)&&std::isfinite(Z)
+            &&X>=NativeOnlyMinimum.X&&X<=NativeOnlyMaximum.X
+            &&Y>=NativeOnlyMinimum.Y&&Y<=NativeOnlyMaximum.Y
+            &&Z>=NativeOnlyMinimum.Z&&Z<=NativeOnlyMaximum.Z;
+    }
+
     static FClassificationThreadStats& ThreadClassificationStats()
     {
         static thread_local FClassificationThreadStats Stats;
@@ -1914,7 +2056,7 @@ private:
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::SurfaceWorld)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -1942,7 +2084,7 @@ private:
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::FloatingIslands)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -4675,6 +4817,12 @@ public:
                               int32 Count,float* OutDensity) const
     {
         if(Count<=0||OutDensity==nullptr)return;
+        if(bNativeOnly)
+        {
+            for(int32 Lane=0;Lane<Count;++Lane)
+                OutDensity[Lane]=DensityAtLattice(X,Y,ZStart+Lane*ZStep);
+            return;
+        }
         bool bHasLegacySurfaceSample=false;
         for(int32 Lane=0;Lane<Count;++Lane)
             bHasLegacySurfaceSample|=UsesLegacySurfaceField(static_cast<float>(X),
@@ -5211,6 +5359,10 @@ private:
     size_t WordsPerZ=0;
     EDetailVariant DetailVariant=EDetailVariant::Coherent;
     bool Built=false;
+    bool bNativeOnly=false;
+    FIntVector NativeOnlyMinimum=FIntVector::ZeroValue;
+    FIntVector NativeOnlyMaximum=FIntVector::ZeroValue;
+    mutable std::atomic<uint32> NativeOnlyViolations{0};
     bool FarBuilt=false;
     std::vector<FInterval> LayerRanges;
     std::vector<FLayerField> LayerFields;

Standalone/Core/src/VoxelForgeCore.cpp

@@ -13,6 +13,8 @@
 #include <set>
 #include <functional>
 #include <thread>
+#include <new>
+#include <stdexcept>
 
 namespace vfcore::detail
 {
@@ -943,6 +945,7 @@ namespace VoxelForgeCore
         std::shared_ptr<const WorldAssemblyManifest> worldAssembly;
         WorldConfiguration configuration;
         std::unique_ptr<FStandaloneShapeWorld> shape;
+        std::atomic<bool> shapeReady{false};
         std::unique_ptr<world_assembly_detail::FSharedHeightfieldColumnCache>
             sharedHeightfieldColumns;
         std::unique_ptr<floating_island_detail::FSharedIslandColumnCache>
@@ -996,9 +999,136 @@ namespace VoxelForgeCore
     World::World(World&&) noexcept=default;
     World& World::operator=(World&&) noexcept=default;
 
+    namespace
+    {
+        template<class TImpl>
+        bool NativeOnlyBoundsForTile(const TImpl& impl,const TileKey& key,
+            FIntVector& minimum,FIntVector& maximum)
+        {
+            if(!impl.owner||key.lod!=0||key.lod>=impl.configuration.fullResolutionLodCount)
+                return false;
+            constexpr std::int64_t TileExtent=CHUNK_SIZE;
+            const std::int64_t skirt=impl.owner->CoreVoxelSizeMicrons>0
+                ?static_cast<std::int64_t>(std::ceil(std::abs(
+                    static_cast<double>(impl.owner->SkirtCells)
+                    *static_cast<double>(impl.owner->OwnerVoxelSizeMicrons)
+                    /static_cast<double>(impl.owner->CoreVoxelSizeMicrons)))):0;
+            const std::int64_t pad=std::max<std::int64_t>(8,skirt+4);
+            const std::int64_t coordinates[3]={key.coordinate.x,key.coordinate.y,key.coordinate.z};
+            std::int64_t low[3]{},high[3]{};
+            for(int axis=0;axis<3;++axis)
+            {
+                const std::int64_t origin=coordinates[axis]*TileExtent;
+                low[axis]=origin-pad;
+                high[axis]=origin+TileExtent+pad;
+                if(low[axis]<std::numeric_limits<std::int32_t>::min()+4ll
+                    ||high[axis]>std::numeric_limits<std::int32_t>::max()-4ll)return false;
+            }
+            minimum=FIntVector(static_cast<int32>(low[0]),static_cast<int32>(low[1]),
+                static_cast<int32>(low[2]));
+            maximum=FIntVector(static_cast<int32>(high[0]),static_cast<int32>(high[1]),
+                static_cast<int32>(high[2]));
+            return true;
+        }
+
+        bool IntersectsBox(const std::array<std::int64_t,3>& minimum,
+            const std::array<std::int64_t,3>& maximum,
+            const std::int64_t tileMinimum[3],const std::int64_t tileMaximum[3])
+        {
+            for(int axis=0;axis<3;++axis)
+                if(maximum[axis]<tileMinimum[axis]||minimum[axis]>tileMaximum[axis])
+                    return false;
+            return true;
+        }
+
+        bool RouteTouchesBox(const WorldAssemblyStratumPlanV1& plan,
+            const std::int64_t tileMinimum[3],const std::int64_t tileMaximum[3])
+        {
+            if(plan.route.empty())return false;
+            const std::int64_t constraintRadius=std::max<std::int64_t>(0,
+                plan.routeConstraints.capsuleRadiusSubvoxels)
+                +std::max<std::int64_t>(0,plan.routeConstraints.capsuleHeightSubvoxels)/2;
+            for(std::size_t index=0;index<plan.route.size();++index)
+            {
+                const auto& point=plan.route[index];
+                const std::int64_t radius=std::max(constraintRadius,
+                    std::max<std::int64_t>(0,point.radiusSubvoxels));
+                std::array<std::int64_t,3> low{},high{};
+                for(int axis=0;axis<3;++axis)
+                {
+                    low[axis]=point.positionSubvoxels[axis]-radius;
+                    high[axis]=point.positionSubvoxels[axis]+radius;
+                }
+                if(IntersectsBox(low,high,tileMinimum,tileMaximum))return true;
+                if(index+1>=plan.route.size())continue;
+                const auto& next=plan.route[index+1];
+                const std::int64_t segmentRadius=std::max(radius,
+                    std::max(constraintRadius,std::max<std::int64_t>(0,next.radiusSubvoxels)));
+                for(int axis=0;axis<3;++axis)
+                {
+                    low[axis]=std::min(point.positionSubvoxels[axis],next.positionSubvoxels[axis])
+                        -segmentRadius;
+                    high[axis]=std::max(point.positionSubvoxels[axis],next.positionSubvoxels[axis])
+                        +segmentRadius;
+                }
+                if(IntersectsBox(low,high,tileMinimum,tileMaximum))return true;
+            }
+            return false;
+        }
+
+        bool OwnerPassageTouchesBox(const FStandaloneOwnerWorld& owner,
+            const FIntVector& minimum,const FIntVector& maximum)
+        {
+            const double ownerToCore=owner.OwnerVoxelSizeMicrons>0
+                &&owner.CoreVoxelSizeMicrons>0
+                ?static_cast<double>(owner.OwnerVoxelSizeMicrons)
+                    /static_cast<double>(owner.CoreVoxelSizeMicrons):1.0;
+            const double padding=(std::max(8.0,static_cast<double>(owner.SkirtCells)+4.0)
+                /ownerToCore)+64.0;
+            const double tileMinimum[3]={static_cast<double>(minimum.X),
+                static_cast<double>(minimum.Y),static_cast<double>(minimum.Z)};
+            const double tileMaximum[3]={static_cast<double>(maximum.X),
+                static_cast<double>(maximum.Y),static_cast<double>(maximum.Z)};
+            const auto SegmentTouches=[&](const FVector& a,const FVector& b,double radius)
+            {
+                for(int axis=0;axis<3;++axis)
+                {
+                    const double pointA=(&a.X)[axis]*ownerToCore;
+                    const double pointB=(&b.X)[axis]*ownerToCore;
+                    const double expansion=(radius+padding)*ownerToCore;
+                    if(std::max(pointA,pointB)+expansion<tileMinimum[axis]
+                        ||std::min(pointA,pointB)-expansion>tileMaximum[axis])return false;
+                }
+                return true;
+            };
+            for(const FVoxelPassage& passage:owner.Manager->GetPassages())
+            {
+                const auto& points=passage.ControlPoints;
+                if(points.Num()<2)
+                {
+                    if(SegmentTouches(passage.UpperPoint,passage.LowerPoint,passage.Radius))
+                        return true;
+                    continue;
+                }
+                for(int32 index=0;index+1<points.Num();++index)
+                {
+                    const double radius=std::max({static_cast<double>(passage.Radius),
+                        passage.ControlRadii.IsValidIndex(index)
+                            ?static_cast<double>(passage.ControlRadii[index]):0.0,
+                        passage.ControlRadii.IsValidIndex(index+1)
+                            ?static_cast<double>(passage.ControlRadii[index+1]):0.0});
+                    if(SegmentTouches(points[index],points[index+1],radius))return true;
+                }
+            }
+            return false;
+        }
+    }
+
     bool World::compile(const ShapeBuildRequest& request,const JobScheduler& scheduler,std::string& error)
     {
         if(!impl_->owner){error="resolved world snapshot is empty";return false;}
+        if(impl_->shapeReady.load(std::memory_order_acquire))
+        {error="world shape is already compiled";return false;}
         if(!::vfcore::fp_contract::selfTest())
         {
             error="Core startup refused: floating-point contraction self-test detected a fused multiply-add; this compiler/flag combination is unsupported for world generation";
@@ -1018,13 +1148,74 @@ namespace VoxelForgeCore
             std::unique_lock lock(impl_->tileRegionMutex);
             impl_->tileRegions.clear();
             impl_->tileRegionCount.store(0,std::memory_order_release);
+            impl_->shapeReady.store(true,std::memory_order_release);
         }
         return ok;
     }
 
+    bool World::isTileShapeFree(const TileKey& key) const
+    {
+        if(!impl_||!impl_->owner||!impl_->worldAssembly||!impl_->owner->Manager
+            ||!impl_->owner->Generator||!impl_->editLog.empty())return false;
+        FIntVector boundsMin,boundsMax;
+        if(!NativeOnlyBoundsForTile(*impl_,key,boundsMin,boundsMax))return false;
+
+        const std::int64_t tileMinimum[3]={boundsMin.X,boundsMin.Y,boundsMin.Z};
+        const std::int64_t tileMaximum[3]={boundsMax.X,boundsMax.Y,boundsMax.Z};
+        const int32 firstSurfaceChunk=FloorDiv(boundsMin.Z,CHUNK_SIZE);
+        const int32 lastSurfaceChunk=FloorDiv(boundsMax.Z,CHUNK_SIZE);
+        const WorldAssemblyStratumPlanV1* selectedPlan=nullptr;
+        for(int32 chunkZ=firstSurfaceChunk;chunkZ<=lastSurfaceChunk;++chunkZ)
+        {
+            if(impl_->owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,chunkZ))
+                !=ECaveGeneratorType::SurfaceWorld)return false;
+            const int32 strateIndex=impl_->owner->Manager->GetStrateIndex(
+                static_cast<float>((static_cast<double>(chunkZ)*CHUNK_SIZE
+                    +CHUNK_SIZE*0.5)*VOXEL_SIZE));
+            const auto found=std::find_if(impl_->worldAssembly->plan.strates.begin(),
+                impl_->worldAssembly->plan.strates.end(),[strateIndex,chunkZ](const auto& plan)
+                {return plan.strateIndex==strateIndex&&chunkZ<=plan.topChunkZ
+                    &&chunkZ>=plan.bottomChunkZ;});
+            if(found==impl_->worldAssembly->plan.strates.end()
+                ||(selectedPlan&&selectedPlan!=&*found))return false;
+            selectedPlan=&*found;
+        }
+        if(!selectedPlan||!Heightfield2D(impl_->worldAssembly->recipe,*selectedPlan).isValid())
+            return false;
+
+        const double coreVoxelsPerOwnerChunk=static_cast<double>(CHUNK_SIZE)
+            *static_cast<double>(impl_->owner->OwnerVoxelSizeMicrons)
+            /static_cast<double>(std::max(1u,impl_->owner->CoreVoxelSizeMicrons));
+        const int32 firstIslandChunk=FMath::FloorToInt(
+            static_cast<double>(boundsMin.Z)/coreVoxelsPerOwnerChunk);
+        const int32 lastIslandChunk=FMath::FloorToInt(
+            static_cast<double>(boundsMax.Z)/coreVoxelsPerOwnerChunk);
+        for(int32 chunkZ=firstIslandChunk;chunkZ<=lastIslandChunk;++chunkZ)
+            if(impl_->owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,chunkZ))
+                ==ECaveGeneratorType::FloatingIslands)return false;
+
+        constexpr std::int64_t scale=WorldAssemblySubvoxelsPerVoxel;
+        const std::int64_t subMinimum[3]={tileMinimum[0]*scale,tileMinimum[1]*scale,
+            tileMinimum[2]*scale};
+        const std::int64_t subMaximum[3]={tileMaximum[0]*scale,tileMaximum[1]*scale,
+            tileMaximum[2]*scale};
+        for(const WorldAssemblyFeatureV1& feature:selectedPlan->features)
+            if(IntersectsBox(feature.minimumSubvoxels,feature.maximumSubvoxels,
+                subMinimum,subMaximum))return false;
+        if(RouteTouchesBox(*selectedPlan,subMinimum,subMaximum))return false;
+        if(OwnerPassageTouchesBox(*impl_->owner,boundsMin,boundsMax))return false;
+        FStandaloneShapeWorld proofGeometry;
+        if(!proofGeometry.BuildShapeDependencyProof(*impl_->owner,boundsMin,boundsMax,
+            impl_->owner->Generator->bStandaloneResearchRoundTunnels))return false;
+        const FIntVector tileOrigin=ToNative(key).OriginVoxels();
+        if(proofGeometry.HasShapeDependencyInBox(tileOrigin,1,CHUNK_SIZE))return false;
+        return true;
+    }
+
     bool World::needsTileRegion(const TileKey& key) const
     {
-        if(!impl_||!impl_->owner||!impl_->shape||!impl_->shape->IsBuilt()
+        if(!impl_||!impl_->owner||!impl_->shapeReady.load(std::memory_order_acquire)
+            ||!impl_->shape||!impl_->shape->IsBuilt()
             ||key.lod<0||key.lod>=impl_->configuration.fullResolutionLodCount)
             return false;
         if(CoveredByBaseShape(impl_->buildRequest,impl_->configuration,key))return false;
@@ -1039,10 +1230,15 @@ namespace VoxelForgeCore
     {
         if(outCompiledTiles)*outCompiledTiles=0;
         if(outStats)*outStats={};
-        if(!impl_||!impl_->owner||!impl_->shape||!impl_->shape->IsBuilt())
+        try
+        {
+        if(!impl_||!impl_->owner||!impl_->shapeReady.load(std::memory_order_acquire)
+            ||!impl_->shape||!impl_->shape->IsBuilt())
         {error="the base world must be compiled before adding tile regions";return false;}
         if(tiles.empty())return true;
 
+        constexpr std::int64_t RegionPadding=10;
+
         struct FPendingRegion
         {
             TileKey pageKey;
@@ -1061,12 +1257,27 @@ namespace VoxelForgeCore
                 const TileKey& key=tiles[inputIndex];
                 if(key.lod<0||key.lod>8)
                 {error="tile region contains an invalid LOD";return false;}
-                if(key.lod>=impl_->configuration.fullResolutionLodCount
-                    ||CoveredByBaseShape(impl_->buildRequest,impl_->configuration,key))continue;
+                if(key.lod>=impl_->configuration.fullResolutionLodCount)continue;
+                const std::int64_t extent=static_cast<std::int64_t>(CHUNK_SIZE)
+                    *(std::int64_t{1}<<key.lod);
+                const std::int32_t coordinates[3]={key.coordinate.x,key.coordinate.y,
+                    key.coordinate.z};
+                for(int axis=0;axis<3;++axis)
+                {
+                    const std::int64_t origin=static_cast<std::int64_t>(coordinates[axis])*extent;
+                    if(origin<std::numeric_limits<std::int32_t>::min()+RegionPadding
+                        ||origin+extent>std::numeric_limits<std::int32_t>::max()-RegionPadding)
+                    {error="tile region coordinate is out of range";return false;}
+                }
+                if(CoveredByBaseShape(impl_->buildRequest,impl_->configuration,key))continue;
                 if(impl_->tileRegions.contains(key)||!seenTiles.insert(key).second)continue;
-                // Analytic regions evaluate only requested fine tiles and can safely coalesce a
-                // whole entering LOD slab. Packed pages retain their fixed absolute parent cells.
-                const TileKey pageKey=analyticOnly?TileKey{{0,0,0},key.lod}:ShapePageKey(key);
+                // Keep every region's bounds spatially finite. A large camera step can bring in
+                // disjoint tiles across the whole view; coalescing an entire LOD slab makes the
+                // dense axis-bin grid grow with the bounding rectangle of all of them at once.
+                // Garder chaque region spatialement bornee: un grand deplacement peut amener des
+                // tuiles disjointes; fusionner tout un niveau ferait croitre les bins avec son
+                // grand rectangle englobant.
+                const TileKey pageKey=ShapePageKey(key);
                 auto [found,inserted]=regionByPage.try_emplace(pageKey,pendingRegions.size());
                 if(inserted)pendingRegions.push_back({pageKey,{}});
                 pendingRegions[found->second].tiles.push_back(key);
@@ -1173,18 +1384,37 @@ namespace VoxelForgeCore
             }
         }
         {
-            std::unique_lock lock(impl_->tileRegionMutex);
+            std::unordered_map<TileKey,std::shared_ptr<FStandaloneShapeWorld>,TileKeyHash> publish;
+            publish.reserve(stats.tileKeysCovered);
             for(std::size_t i=0;i<pendingRegions.size();++i)
-            {
                 for(const TileKey& key:pendingRegions[i].tiles)
-                    if(impl_->tileRegions.try_emplace(key,compiledRegions[i]).second)++compiledTileCount;
-            }
+                    publish.try_emplace(key,compiledRegions[i]);
+            const std::size_t candidates=publish.size();
+            std::unique_lock lock(impl_->tileRegionMutex);
+            impl_->tileRegions.reserve(impl_->tileRegions.size()+candidates);
+            impl_->tileRegions.merge(publish);
+            compiledTileCount=candidates-publish.size();
             impl_->tileRegionCount.store(impl_->tileRegions.size(),std::memory_order_release);
         }
         stats.wallSeconds=std::chrono::duration<double>(Clock::now()-compileStart).count();
         if(outCompiledTiles)*outCompiledTiles=compiledTileCount;
         if(outStats)*outStats=stats;
         return true;
+        }
+        catch(const std::bad_alloc&)
+        {
+            if(outCompiledTiles)*outCompiledTiles=0;
+            if(outStats)*outStats={};
+            error="region OOM";
+            return false;
+        }
+        catch(const std::length_error&)
+        {
+            if(outCompiledTiles)*outCompiledTiles=0;
+            if(outStats)*outStats={};
+            error="region size";
+            return false;
+        }
     }
 
     void World::retainTileRegions(std::span<const TileKey> desiredTiles)
@@ -1201,14 +1431,17 @@ namespace VoxelForgeCore
     }
 
     void World::buildFarWorld()
-    { if(impl_->shape)impl_->shape->BuildFarWorld(); }
-    bool World::isCompiled() const noexcept { return impl_&&impl_->shape&&impl_->shape->IsBuilt(); }
-    bool World::hasFarWorld() const noexcept { return impl_&&impl_->shape&&impl_->shape->HasFarWorld(); }
+    { if(impl_&&impl_->shapeReady.load(std::memory_order_acquire)&&impl_->shape)impl_->shape->BuildFarWorld(); }
+    bool World::isCompiled() const noexcept
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire); }
+    bool World::hasFarWorld() const noexcept
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire)
+        &&impl_->shape&&impl_->shape->HasFarWorld(); }
 
     ShapeBuildStats World::buildStats() const
     {
         ShapeBuildStats out;
-        if(!impl_||!impl_->shape)return out;
+        if(!impl_||!impl_->shapeReady.load(std::memory_order_acquire)||!impl_->shape)return out;
         const auto& stats=impl_->shape->GetStats();
         out.shapeSeconds=stats.ShapeSeconds;out.intervalSeconds=stats.IntervalSeconds;
         out.surfaceSeconds=stats.SurfaceSeconds;out.farShapeSeconds=stats.FarShapeSeconds;
@@ -1218,18 +1451,19 @@ namespace VoxelForgeCore
     }
 
     float World::densityAt(Vec3d position) const
-    { return impl_&&impl_->shape?impl_->shape->DensityAt(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):0.0f; }
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire)&&impl_->shape?impl_->shape->DensityAt(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):0.0f; }
     float World::unclampedDensityAt(Vec3d position) const
-    { return impl_&&impl_->shape?impl_->shape->DensityAtUnclamped(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):0.0f; }
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire)&&impl_->shape?impl_->shape->DensityAtUnclamped(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):0.0f; }
     DetailFieldSample World::detailSampleAt(Vec3d position) const
-    { return impl_&&impl_->shape?impl_->shape->DetailSampleAt(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):DetailFieldSample{}; }
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire)&&impl_->shape?impl_->shape->DetailSampleAt(static_cast<float>(position.x),static_cast<float>(position.y),static_cast<float>(position.z)):DetailFieldSample{}; }
     float World::densityAtLattice(Vec3i position) const
-    { return impl_&&impl_->shape?impl_->shape->DensityAtLattice(position.x,position.y,position.z):0.0f; }
+    { return impl_&&impl_->shapeReady.load(std::memory_order_acquire)&&impl_->shape?impl_->shape->DensityAtLattice(position.x,position.y,position.z):0.0f; }
     bool World::isSolidAt(Vec3d position) const { return densityAt(position)<0.0f; }
 
     bool World::isSolidAlongSegment(Vec3d start,Vec3d end,double spacing) const
     {
-        if(!impl_||!impl_->shape||!std::isfinite(spacing)||spacing<=0.0)return false;
+        if(!impl_||!impl_->shapeReady.load(std::memory_order_acquire)||!impl_->shape
+            ||!std::isfinite(spacing)||spacing<=0.0)return false;
         const double dx=end.x-start.x,dy=end.y-start.y,dz=end.z-start.z;
         const double length=std::sqrt(dx*dx+dy*dy+dz*dz);
         const std::size_t intervals=std::max<std::size_t>(1,static_cast<std::size_t>(std::ceil(length/spacing)));
@@ -1243,7 +1477,7 @@ namespace VoxelForgeCore
 
     TileClass World::classifyBox(Vec3i origin,std::int32_t step,std::int32_t cells) const
     {
-        if(!impl_||!impl_->shape)return TileClass::mixed;
+        if(!impl_||!impl_->shapeReady.load(std::memory_order_acquire)||!impl_->shape)return TileClass::mixed;
         const EVoxelTileClass result=impl_->shape->ClassifyBox(ToNative(origin),step,cells);
         return result==EVoxelTileClass::AllSolid?TileClass::allSolid:
             result==EVoxelTileClass::AllAir?TileClass::allAir:TileClass::mixed;
@@ -1365,20 +1599,38 @@ namespace VoxelForgeCore
         // Les tuiles proches n'avaient aucun conflit; garder leur acces simple et associer les LOD grossiers.
         Heightfield2D::setThreadColumnCacheLegacyDirectMapped(
             options.legacyDirectMappedColumnCache||key.lod<=2);
-        if(!impl_||!impl_->owner||!impl_->shape||!impl_->shape->IsBuilt())
-        { error="world must be compiled before generating tiles";return std::nullopt; }
+        if(!impl_||!impl_->owner)
+        { error="resolved world snapshot is empty";return std::nullopt; }
+        const bool bShapeReady=impl_->shapeReady.load(std::memory_order_acquire);
+        const bool bNativeOnly=!bShapeReady||options.diagnosticForceNativeOnly;
+        if(!bShapeReady&&!options.diagnosticForceNativeOnly&&!isTileShapeFree(key))
+        {error="tile is shape-dependent and must wait for shape compilation";return std::nullopt;}
+        if(!bNativeOnly&&(!impl_->shape||!impl_->shape->IsBuilt()))
+        {error="world shape publication is incomplete";return std::nullopt;}
         FScopedSharedColumnCaches sharedColumnCaches(options.useSharedColumnCache
                 ?impl_->sharedHeightfieldColumns.get():nullptr,
             options.useSharedColumnCache?impl_->sharedIslandColumns.get():nullptr);
         const auto& world=*impl_->owner;
+        FStandaloneShapeWorld nativeOnlyShape;
+        FIntVector nativeOnlyMinimum,nativeOnlyMaximum;
         std::shared_ptr<FStandaloneShapeWorld> page;
-        if(impl_->tileRegionCount.load(std::memory_order_acquire)!=0)
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyBoundsForTile(*impl_,key,nativeOnlyMinimum,nativeOnlyMaximum))
+            {error="shape-free guard: tile has no bounded native-only domain";return std::nullopt;}
+            if(!options.diagnosticForceNativeOnly&&!isTileShapeFree(key))
+            {error="shape-free guard: tile failed the native-only readiness proof";return std::nullopt;}
+            nativeOnlyShape.InitializeNativeSurfaceOnly(*impl_->owner,impl_->worldAssembly.get(),
+                nativeOnlyMinimum,nativeOnlyMaximum);
+        }
+        else if(impl_->tileRegionCount.load(std::memory_order_acquire)!=0)
         {
             std::shared_lock lock(impl_->tileRegionMutex);
             if(const auto found=impl_->tileRegions.find(key);found!=impl_->tileRegions.end())
                 page=found->second;
         }
-        const FStandaloneShapeWorld* tileShapeContext=page?page.get():impl_->shape.get();
+        const FStandaloneShapeWorld* tileShapeContext=bNativeOnly?&nativeOnlyShape:
+            (page?page.get():impl_->shape.get());
         UVoxelMarchingCubesMesher mesher;
         mesher.SetGenerator(world.Generator.get());
         mesher.SetGeometryVoxelSizeCm(static_cast<float>(world.CoreVoxelSizeMicrons)/10000.0f);
@@ -1435,6 +1687,12 @@ namespace VoxelForgeCore
             }
             if(!sharpFeatures.IsEmpty())
             {
+                if(bNativeOnly)
+                {
+                    nativeOnlyShape.RecordNativeOnlyViolation();
+                    error="shape-free guard: tile intersects a shape feature";
+                    return std::nullopt;
+                }
                 // Streamed analytic pages omit the native assembly plan. Use the immutable base
                 // shape only for tagged tiles so their mesher samples the same field as the tags.
                 // Les pages analytiques omettent le plan natif ; utiliser la base uniquement pour
@@ -1493,7 +1751,7 @@ namespace VoxelForgeCore
         out.diagnostics.featureRefinedResolution=bFeatureRefinedResolution;
         const bool bHasWorldAssembly=impl_->worldAssembly!=nullptr;
         const bool bNeedsFarShell=bHasWorldAssembly&&key.lod>=7
-            &&(tileShape.HasFarWorld()||impl_->shape->HasFarWorld());
+            &&(tileShape.HasFarWorld()||(bShapeReady&&impl_->shape->HasFarWorld()));
         bool bOverlapsPlayerEdit=false;
         if(tileShape.HasEditTransaction())
         {
@@ -1767,6 +2025,11 @@ namespace VoxelForgeCore
             Heightfield2D::setThreadColumnOctaveDrop(PreviousOctaveDrop);
             Heightfield2D::setThreadColumnInterpolationStrideSubvoxels(PreviousInterpolationStride);
         }
+        if(bNativeOnly&&tileShape.GetNativeOnlyViolationCount()!=0)
+        {
+            error="shape-free guard caught a mesher read outside the native SurfaceWorld field";
+            return std::nullopt;
+        }
         const double MarchingCubesWallMilliseconds=std::chrono::duration<double,std::milli>(
             std::chrono::steady_clock::now()-MarchingCubesStart).count();
         const double ColumnMillisecondsAfterMeshing=
@@ -1801,7 +2064,8 @@ namespace VoxelForgeCore
             std::chrono::steady_clock::now()-MeshingStart).count();
         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;
+        const FStandaloneShapeWorld& farShape=tileShape.HasFarWorld()?tileShape:
+            (bShapeReady?*impl_->shape:tileShape);
         out.diagnostics.farShellRepairSkipped=bSkipFarShellRepair;
         if(farShape.HasFarWorld()&&!bSkipFarShellRepair)
         {