refactor(core): bind generator fields once per resolved strate (L40, migration step 2); research R7

SurfaceWorld, FloatingIslands and legacy evaluators sit behind one immutable densityAt adapter held in
a variant (no virtual call per sample); BindResolvedStratumFields builds a sorted strate table at world
setup, so DensityAt, native SW/FI sampling and ClassifyBoxDetailed no longer ask the strate manager per
sample. No arithmetic change: owner hashes identical to L37/L39 at W1/W12. Cost vs L39: FI -0.66%,
SW -1.31% (noise). verify fast/medium/full PASS (full re-run alone: 407 gates).
Research R7: disk cache design for UE5/Windows/multiplayer and a zlib probe (about 1/3 size, 0.1 ms/tile).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Core/src/ShapeWorldInternal.h

@@ -25,6 +25,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include <utility>
+#include <variant>
 #include <vector>
 
 // Standalone-only world compiler. It compiles the runtime room/tunnel/passages into
@@ -41,6 +42,114 @@ public:
         double SealThickness=0.0;
     };
 
+    // Immutable adapters share densityAt(x,y,z,out) without a virtual call in the sample
+    // loop. The variant is selected once per resolved strate; callers retain concrete access
+    // to fixed-point and interval operations where the legacy arithmetic requires them.
+    struct FSurfaceWorldFieldAdapter
+    {
+        VoxelForgeCore::Heightfield2D Evaluator;
+        FSurfaceWorldFieldAdapter(const VoxelForgeCore::WorldAssemblyRecipeV1& Recipe,
+            const VoxelForgeCore::WorldAssemblyStratumPlanV1& Plan) noexcept
+            :Evaluator(Recipe,Plan){}
+
+        bool densityAt(float X,float Y,float Z,float& OutDensity) const noexcept
+        {
+            if(!std::isfinite(X)||!std::isfinite(Y)||!std::isfinite(Z))return false;
+            constexpr double Scale=static_cast<double>(
+                VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
+            const double MaxVoxel=static_cast<double>(std::numeric_limits<int64>::max())/Scale;
+            if(std::abs(static_cast<double>(X))>MaxVoxel
+                ||std::abs(static_cast<double>(Y))>MaxVoxel
+                ||std::abs(static_cast<double>(Z))>MaxVoxel)return false;
+            const auto ToFixed=[](float Value)
+            {return static_cast<int64>(std::llround(static_cast<double>(Value)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel));};
+            if(!Evaluator.isValid())return false;
+            OutDensity=static_cast<float>(Evaluator.point(ToFixed(X),ToFixed(Y),ToFixed(Z))
+                .densitySubvoxels/Scale);
+            return true;
+        }
+    };
+
+    struct FFloatingIslandFieldAdapter
+    {
+        VoxelForgeCore::FloatingIslandFieldV1 Evaluator;
+        int32 BottomChunkZ=0;
+        std::vector<FFloatingIslandParams> LegacyBoundaryParams;
+
+        FFloatingIslandFieldAdapter(const VoxelForgeCore::FloatingIslandRecipeV1& Recipe,
+            const VoxelForgeCore::FloatingIslandPlanV1& Plan,int32 InBottomChunkZ,
+            int32 InTopChunkZ,const UVoxelStrateManager* Manager)
+            :Evaluator(Recipe,Plan),BottomChunkZ(InBottomChunkZ)
+        {
+            if(Manager&&Recipe.geometryVersion<4&&InTopChunkZ>=InBottomChunkZ)
+            {
+                LegacyBoundaryParams.reserve(static_cast<std::size_t>(
+                    static_cast<int64>(InTopChunkZ)-InBottomChunkZ+1));
+                for(int32 ChunkZ=InBottomChunkZ;ChunkZ<=InTopChunkZ;++ChunkZ)
+                    LegacyBoundaryParams.push_back(Manager->GetFloatingIslandParamsForChunk(
+                        FIntVector(0,0,ChunkZ)));
+            }
+        }
+
+        std::int64_t densitySubvoxelsAt(std::int64_t X,std::int64_t Y,
+            std::int64_t Z) const noexcept
+        {return Evaluator.densitySubvoxels(X,Y,Z);}
+
+        const FFloatingIslandParams* legacyBoundaryParamsAt(int32 ChunkZ) const noexcept
+        {
+            const int64 Index=static_cast<int64>(ChunkZ)-BottomChunkZ;
+            return Index>=0&&static_cast<std::size_t>(Index)<LegacyBoundaryParams.size()
+                ?&LegacyBoundaryParams[static_cast<std::size_t>(Index)]:nullptr;
+        }
+
+        bool densityAt(float X,float Y,float Z,float& OutDensity) const noexcept
+        {
+            if(!Evaluator.isValid()||!std::isfinite(X)||!std::isfinite(Y)
+                ||!std::isfinite(Z))return false;
+            constexpr double Scale=static_cast<double>(
+                VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
+            constexpr double Maximum=1000000000000.0/Scale;
+            if(std::abs(static_cast<double>(X))>Maximum
+                ||std::abs(static_cast<double>(Y))>Maximum
+                ||std::abs(static_cast<double>(Z))>Maximum)return false;
+            const auto ToFixed=[](float Value)
+            {return static_cast<int64>(std::llround(static_cast<double>(Value)
+                *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel));};
+            OutDensity=static_cast<float>(static_cast<double>(densitySubvoxelsAt(
+                ToFixed(X),ToFixed(Y),ToFixed(Z)))/Scale);
+            return std::isfinite(OutDensity);
+        }
+    };
+
+    struct FLegacyGeneratorFieldAdapter
+    {
+        const UVoxelGenerator* Generator=nullptr;
+        bool densityAt(float X,float Y,float Z,float& OutDensity) const
+        {
+            if(!Generator)return false;
+            OutDensity=Generator->GetDensityAt(X,Y,Z);
+            return std::isfinite(OutDensity);
+        }
+    };
+
+    using FGeneratorFieldAdapterV1=std::variant<std::monostate,
+        FSurfaceWorldFieldAdapter,FFloatingIslandFieldAdapter,
+        FLegacyGeneratorFieldAdapter>;
+
+    struct FBoundStratumField
+    {
+        enum class EKind : uint8 { Legacy, SurfaceWorld, FloatingIslands };
+        const VoxelForgeCore::ResolvedLayoutStratumV2* Resolved=nullptr;
+        const VoxelForgeCore::WorldAssemblyStratumPlanV1* SurfacePlan=nullptr;
+        const VoxelForgeCore::WorldAssemblyFloatingIslandPlanV1* IslandPlan=nullptr;
+        FGeneratorFieldAdapterV1 Evaluator;
+        int32 StrateIndex=-1;
+        int32 BottomChunkZ=0;
+        int32 TopChunkZ=-1;
+        EKind Kind=EKind::Legacy;
+    };
+
     const std::vector<FStandalonePassageVoidCrossing>& GetPassageVoidCrossings() const
     {return PassageVoidCrossings;}
 
@@ -170,6 +279,117 @@ public:
         return it==ResolvedLayout->strates.end()?nullptr:&*it;
     }
 
+    void BindResolvedStratumFields()
+    {
+        BoundStratumFields.clear();
+        BoundManagerLayoutChunkWidthVoxels=Owner&&Owner->Manager
+            ?Owner->Manager->GetStrateLayoutChunkWidthVoxels():0.0f;
+        if(!ResolvedLayout||ResolvedLayout->strateLayoutChunkSizeMicrometres<=0)return;
+        const int64 ChunkWidthMicrometres=ResolvedLayout->strateLayoutChunkSizeMicrometres;
+        const auto FloorDiv64=[](int64 Value,int64 Divisor)
+        {
+            const int64 Quotient=Value/Divisor;
+            const int64 Remainder=Value%Divisor;
+            return Remainder<0?Quotient-1:Quotient;
+        };
+        BoundStratumFields.reserve(ResolvedLayout->strates.size());
+        for(const auto& Stratum:ResolvedLayout->strates)
+        {
+            if(Stratum.strateIndex<0
+                ||Stratum.interiorTopMicrometres<=Stratum.interiorBottomMicrometres)
+                continue;
+            const int64 Bottom=FloorDiv64(Stratum.interiorBottomMicrometres,
+                ChunkWidthMicrometres);
+            const int64 Top=FloorDiv64(Stratum.interiorTopMicrometres-1,
+                ChunkWidthMicrometres);
+            if(Bottom<std::numeric_limits<int32>::min()
+                ||Bottom>std::numeric_limits<int32>::max()
+                ||Top<std::numeric_limits<int32>::min()
+                ||Top>std::numeric_limits<int32>::max()||Top<Bottom)continue;
+
+            FBoundStratumField Bound;
+            Bound.Resolved=&Stratum;
+            Bound.StrateIndex=Stratum.strateIndex;
+            Bound.BottomChunkZ=static_cast<int32>(Bottom);
+            Bound.TopChunkZ=static_cast<int32>(Top);
+            if(Stratum.generatorKind=="SurfaceWorld")
+            {
+                Bound.Kind=FBoundStratumField::EKind::SurfaceWorld;
+                if(WorldAssembly)
+                {
+                    const auto Plan=std::find_if(WorldAssembly->plan.strates.begin(),
+                        WorldAssembly->plan.strates.end(),[&](const auto& Candidate)
+                        {return Candidate.strateIndex==Bound.StrateIndex
+                            &&Candidate.bottomChunkZ==Bound.BottomChunkZ
+                            &&Candidate.topChunkZ==Bound.TopChunkZ;});
+                    if(Plan!=WorldAssembly->plan.strates.end())
+                    {
+                        Bound.SurfacePlan=&*Plan;
+                        FSurfaceWorldFieldAdapter Adapter(WorldAssembly->recipe,*Plan);
+                        if(Adapter.Evaluator.isValid())
+                            Bound.Evaluator.emplace<FSurfaceWorldFieldAdapter>(
+                                std::move(Adapter));
+                    }
+                }
+            }
+            else if(Stratum.generatorKind=="FloatingIslands")
+            {
+                Bound.Kind=FBoundStratumField::EKind::FloatingIslands;
+                if(WorldAssembly)
+                {
+                    const auto Plan=std::find_if(WorldAssembly->floatingIslands.begin(),
+                        WorldAssembly->floatingIslands.end(),[&](const auto& Candidate)
+                        {return Candidate.strateIndex==Bound.StrateIndex
+                            &&Candidate.bottomChunkZ==Bound.BottomChunkZ
+                            &&Candidate.topChunkZ==Bound.TopChunkZ;});
+                    if(Plan!=WorldAssembly->floatingIslands.end())
+                    {
+                        Bound.IslandPlan=&*Plan;
+                        Bound.Evaluator.emplace<FFloatingIslandFieldAdapter>(
+                            Plan->manifest.recipe,Plan->manifest.plan,
+                            Bound.BottomChunkZ,Bound.TopChunkZ,
+                            Owner?Owner->Manager.get():nullptr);
+                    }
+                }
+            }
+            if(std::holds_alternative<std::monostate>(Bound.Evaluator))
+                Bound.Evaluator.emplace<FLegacyGeneratorFieldAdapter>(
+                    FLegacyGeneratorFieldAdapter{Owner?Owner->Generator.get():nullptr});
+            BoundStratumFields.push_back(std::move(Bound));
+        }
+        std::sort(BoundStratumFields.begin(),BoundStratumFields.end(),
+            [](const auto& A,const auto& B){return A.BottomChunkZ<B.BottomChunkZ;});
+    }
+
+    const FBoundStratumField* FindBoundStratumForChunk(int32 ChunkZ) const
+    {
+        const auto Upper=std::upper_bound(BoundStratumFields.begin(),
+            BoundStratumFields.end(),ChunkZ,[](int32 Z,const auto& Field)
+                {return Z<Field.BottomChunkZ;});
+        if(Upper==BoundStratumFields.begin())return nullptr;
+        const auto& Candidate=*std::prev(Upper);
+        return ChunkZ<=Candidate.TopChunkZ?&Candidate:nullptr;
+    }
+
+    const FBoundStratumField* FindBoundStratumForZ(float Z) const
+    {
+        if(!std::isfinite(Z))return nullptr;
+        const float LayoutWidth=static_cast<float>(GetResolvedLayoutChunkWidthVoxels());
+        if(!(LayoutWidth>0.0f))return nullptr;
+        return FindBoundStratumForChunk(FMath::FloorToInt(Z/LayoutWidth));
+    }
+
+    const FBoundStratumField* FindBoundStratumForManagerZ(float Z) const
+    {
+        if(!std::isfinite(Z)||!Owner||!(BoundManagerLayoutChunkWidthVoxels>0.0f))
+            return nullptr;
+        const float WorldZCentimetres=static_cast<float>(
+            static_cast<double>(Z)*GetCoreVoxelSizeCm());
+        const int32 ChunkZ=FMath::FloorToInt((WorldZCentimetres/VOXEL_SIZE)
+            /BoundManagerLayoutChunkWidthVoxels);
+        return FindBoundStratumForChunk(ChunkZ);
+    }
+
     const VoxelForgeCore::ResolvedLayoutStratumV2* FindResolvedLayoutStratumByOrder(int32 Order) const
     {
         if(!ResolvedLayout||Order<0)return nullptr;
@@ -479,10 +699,9 @@ public:
             // samples. The merged intervals are conservative, so a positive is safe.
             return true;
         }
-        if(!ResolvedLayout||!Owner||!Owner->Manager||!std::isfinite(Z))return false;
-        const double worldZCentimetres=static_cast<double>(Z)*GetCoreVoxelSizeCm();
-        const int32 strateIndex=Owner->Manager->GetStrateIndex(static_cast<float>(worldZCentimetres));
-        const auto* stratum=FindResolvedLayoutStratum(strateIndex);
+        if(!ResolvedLayout||!Owner||!std::isfinite(Z))return false;
+        const FBoundStratumField* bound=FindBoundStratumForManagerZ(Z);
+        const auto* stratum=bound?FindResolvedLayoutStratum(bound->StrateIndex):nullptr;
         if(!stratum)return false;
         const double zMicrometres=static_cast<double>(Z)*Owner->CoreVoxelSizeMicrons;
         const auto solidAt=[&](const VoxelForgeCore::ResolvedLayoutBandV2& band)
@@ -538,7 +757,7 @@ public:
                 return density;
             }
         }
-        if(!ResolvedLayout||!Owner||!Owner->Manager||Owner->CoreVoxelSizeMicrons==0
+        if(!ResolvedLayout||!Owner||Owner->CoreVoxelSizeMicrons==0
             ||!std::isfinite(Z))return density;
         const double zMicrometres=static_cast<double>(Z)*Owner->CoreVoxelSizeMicrons;
         if(ResolvedLayout->strates.size()==2)
@@ -600,9 +819,8 @@ public:
                 }
             }
         }
-        const double worldZCentimetres=static_cast<double>(Z)*GetCoreVoxelSizeCm();
-        const int32 strateIndex=Owner->Manager->GetStrateIndex(static_cast<float>(worldZCentimetres));
-        const auto* stratum=FindResolvedLayoutStratum(strateIndex);
+        const FBoundStratumField* bound=FindBoundStratumForManagerZ(Z);
+        const auto* stratum=bound?FindResolvedLayoutStratum(bound->StrateIndex):nullptr;
         if(!stratum)return density;
         const auto solidAt=[&](const VoxelForgeCore::ResolvedLayoutBandV2& band)
         {return band.presentInCurrentField&&zMicrometres>=band.bottomMicrometres
@@ -1665,7 +1883,7 @@ public:
 
     bool GetResolvedStratumBounds(const FStrateSlot& Slot,FResolvedStratumBounds& Out) const
     {
-        if(!Owner||!Owner->Manager)return false;
+        if(!Owner)return false;
         if(const auto* resolved=FindResolvedLayoutStratum(Slot.StrateIndex))
         {
             const double coreMicrons=std::max<std::uint32_t>(1,Owner->CoreVoxelSizeMicrons);
@@ -1678,11 +1896,11 @@ public:
             return MakeResolvedStratumBounds(bottom,top,std::max(ceiling,bedrock),Out);
         }
         const int32 MidChunkZ=(Slot.TopChunkZ+Slot.BottomChunkZ)/2;
-        if(bUseNativeManifestFields&&WorldAssembly
-            &&Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,MidChunkZ))
-                ==ECaveGeneratorType::FloatingIslands)
+        const FBoundStratumField* Bound=FindBoundStratumForChunk(MidChunkZ);
+        if(bUseNativeManifestFields&&WorldAssembly&&Bound
+            &&Bound->Kind==FBoundStratumField::EKind::FloatingIslands)
         {
-            const auto* Plan=FindWorldAssemblyFloatingIslandStratum(Slot.StrateIndex,MidChunkZ);
+            const auto* Plan=Bound->IslandPlan;
             if(Plan&&Plan->manifest.recipe.geometryVersion>=3)
             {
                 constexpr double Scale=static_cast<double>(
@@ -1989,6 +2207,7 @@ public:
         WorkerCount=std::clamp(Workers,1,16);DetailVariant=Variant;
         Scheduler=InScheduler;RoundTunnelsEnabled=bInRoundTunnels;
         bUseNativeManifestFields=true;
+        BindResolvedStratumFields();
         bAnalyticOnly=false;
         bProfileDetailBand=bInProfileDetailBand;
         for(int32 A=0;A<3;++A)
@@ -2162,6 +2381,7 @@ public:
         // Analytic pages retain their bounded owner bins for route bookkeeping. Once published,
         // the Core world binds each page to its base shape as the single density evaluator.
         bUseNativeManifestFields=true;
+        BindResolvedStratumFields();
         RoundTunnelsEnabled=bInRoundTunnels;bAnalyticOnly=true;bProfileDetailBand=false;
         for(int32 A=0;A<3;++A)
         {
@@ -2199,6 +2419,7 @@ public:
         Owner=&World;WorldAssembly=InWorldAssembly;ResolvedLayout=InResolvedLayout;
         NativeOnlyMinimum=InMinimum;NativeOnlyMaximum=InMaximum;
         bUseNativeManifestFields=true;bNativeOnly=true;bAnalyticOnly=true;Built=true;
+        BindResolvedStratumFields();
         NativeOnlyViolations.store(0,std::memory_order_relaxed);
     }
 
@@ -2742,23 +2963,13 @@ public:
         if(NativeFloatingIslandDensityAt(X,Y,Z,Density))return "FloatingIslands-native";
         if(NativeSurfaceDensityAt(X,Y,Z,Density))return "SurfaceWorld-native";
         if(UsesLegacySurfaceField(X,Y,Z))return "SurfaceWorld-legacy";
-        if(Owner&&Owner->Manager)
+        const FBoundStratumField* Bound=FindBoundStratumForZ(Z);
+        if(Bound&&Bound->Resolved)
         {
-            const int32 ChunkZ=FMath::FloorToInt(Z/static_cast<float>(GetResolvedLayoutChunkWidthVoxels()));
-            const ECaveGeneratorType Type=Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ));
-            switch(Type)
-            {
-            case ECaveGeneratorType::TunnelNetwork:return "compiled-analytic/TunnelNetwork";
-            case ECaveGeneratorType::FlatPlain:return "compiled-analytic/FlatPlain";
-            case ECaveGeneratorType::CrystalChamber:return "compiled-analytic/CrystalChamber";
-            case ECaveGeneratorType::Maze:return "compiled-analytic/Maze";
-            case ECaveGeneratorType::SurfaceWorld:return "compiled-analytic/SurfaceWorld";
-            case ECaveGeneratorType::VerticalShafts:return "compiled-analytic/VerticalShafts";
-            case ECaveGeneratorType::FloatingIslands:return "compiled-analytic/FloatingIslands";
-            case ECaveGeneratorType::Underwater:return "compiled-analytic/Underwater";
-            }
+            const std::string& Kind=Bound->Resolved->generatorKind;
+            return "compiled-analytic/"+Kind;
         }
-        return "compiled-analytic/fallback";
+        return Owner?"compiled-analytic/TunnelNetwork":"compiled-analytic/fallback";
     }
 
     float DensityAtLattice(int32 X,int32 Y,int32 Z) const
@@ -3672,7 +3883,10 @@ private:
             &&!NativeSurfaceDensityAt(X,Y,Z,density))
         {
             if(UsesLegacySurfaceField(X,Y,Z)&&Owner&&Owner->Generator)
-                density=Owner->Generator->GetDensityAt(X,Y,Z);
+            {
+                if(!LegacyGeneratorDensityAt(X,Y,Z,density))
+                    density=Owner->Generator->GetDensityAt(X,Y,Z);
+            }
             else
                 density=AnalyticDensityAt(X,Y,Z,true,nullptr,nullptr,nullptr,
                     false,false);
@@ -3961,7 +4175,9 @@ private:
                     NativeDensity=ApplyResolvedStrateComposition(NativeDensity,X,Y,Z);
                 return bApplyEdits?ApplyEditBrushes(NativeDensity,X,Y,Z):NativeDensity;
             }
-            const float Density=Owner->Generator->GetDensityAt(X,Y,Z);
+            float Density=0.0f;
+            if(!LegacyGeneratorDensityAt(X,Y,Z,Density))
+                Density=Owner->Generator->GetDensityAt(X,Y,Z);
             const float composed=bApplyComposition
                 ?ApplyResolvedStrateComposition(Density,X,Y,Z):Density;
             return bApplyEdits?ApplyEditBrushes(composed,X,Y,Z):composed;
@@ -4019,23 +4235,19 @@ public:
     {
         if(SharedDensitySource)
             return SharedDensitySource->GetNativeSurfaceHeightsAt(X,Y,ChunkZ,OutGroundZ,OutCeilingZ);
-        if(!WorldAssembly||!ResolvedLayout||!Owner||!Owner->Manager||!Owner->Generator
+        if(!WorldAssembly||!ResolvedLayout||!Owner||!Owner->Generator
             ||!std::isfinite(X)||!std::isfinite(Y))return false;
         const double ChunkWidth=GetResolvedLayoutChunkWidthVoxels();
         const std::int64_t chunkMinimum=static_cast<std::int64_t>(std::llround(ChunkZ*ChunkWidth));
         const std::int64_t chunkMaximum=static_cast<std::int64_t>(std::llround((ChunkZ+1)*ChunkWidth));
+        const FBoundStratumField* Bound=FindBoundStratumForChunk(ChunkZ);
+        const auto* Field=Bound?std::get_if<FSurfaceWorldFieldAdapter>(&Bound->Evaluator):nullptr;
         if(bNativeOnly&&(!NativeOnlyContainsColumn(X,Y)
             ||chunkMaximum<NativeOnlyMinimum.Z||chunkMinimum>NativeOnlyMaximum.Z
-            ||Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
-                !=ECaveGeneratorType::SurfaceWorld))
+            ||!Bound||Bound->Kind!=FBoundStratumField::EKind::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)+0.5)
-                *ResolvedLayout->strateLayoutChunkSizeMicrometres/10000.0));
-        const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
-        if(!Plan)return false;
+        if(!Bound||Bound->Kind!=FBoundStratumField::EKind::SurfaceWorld
+            ||!Bound->SurfacePlan||!Field||!Field->Evaluator.isValid())return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
         const double MaxVoxel=static_cast<double>(std::numeric_limits<int64>::max())/Scale;
         if(std::abs(static_cast<double>(X))>MaxVoxel||std::abs(static_cast<double>(Y))>MaxVoxel)
@@ -4043,9 +4255,7 @@ public:
         const auto ToFixed=[](float Value)
         {return static_cast<int64>(std::llround(static_cast<double>(Value)
             *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel));};
-        const VoxelForgeCore::Heightfield2D Block(WorldAssembly->recipe,*Plan);
-        if(!Block.isValid())return false;
-        const auto Column=Block.point(ToFixed(X),ToFixed(Y),
+        const auto Column=Field->Evaluator.point(ToFixed(X),ToFixed(Y),
             static_cast<int64>(ChunkZ)*ResolvedLayout->strateLayoutChunkWidthSubvoxels);
         OutGroundZ=static_cast<float>(Column.groundHeightSubvoxels/Scale);
         OutCeilingZ=static_cast<float>(Column.capHeightSubvoxels/Scale);
@@ -4058,25 +4268,22 @@ public:
     bool IsNativeSurfaceBox(const FIntVector& Origin,int32 Step,int32 Cells) const
     {
         if(SharedDensitySource)return SharedDensitySource->IsNativeSurfaceBox(Origin,Step,Cells);
-        if(!WorldAssembly||!Owner||!Owner->Manager||Step<=0||Cells<=0)return false;
+        if(!WorldAssembly||!ResolvedLayout||!Owner||Step<=0||Cells<=0)return false;
         const int32 Pad=std::max(Step,1);
         const int32 BMin=Origin.Z-Pad;
         const int32 BMax=Origin.Z+(Cells+1)*Step;
         const float LayoutWidth=static_cast<float>(GetResolvedLayoutChunkWidthVoxels());
         const int32 FirstChunk=FMath::FloorToInt(static_cast<float>(BMin)/LayoutWidth);
         const int32 LastChunk=FMath::FloorToInt(static_cast<float>(BMax)/LayoutWidth);
-        const VoxelForgeCore::WorldAssemblyStratumPlanV1* Plan=nullptr;
+        const FBoundStratumField* BoundPlan=nullptr;
         for(int32 ChunkZ=FirstChunk;ChunkZ<=LastChunk;++ChunkZ)
         {
-            const auto It=std::find_if(WorldAssembly->plan.strates.begin(),
-                WorldAssembly->plan.strates.end(),[ChunkZ](const auto& Entry)
-                {return ChunkZ<=Entry.topChunkZ&&ChunkZ>=Entry.bottomChunkZ;});
-            if(It==WorldAssembly->plan.strates.end())return false;
-            const auto* Candidate=&*It;
-            if(Plan&&Plan!=Candidate)return false;
-            if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
-                !=ECaveGeneratorType::SurfaceWorld)return false;
-            Plan=Candidate;
+            const auto* Candidate=FindBoundStratumForChunk(ChunkZ);
+            if(!Candidate||Candidate->Kind!=FBoundStratumField::EKind::SurfaceWorld
+                ||!Candidate->SurfacePlan||ChunkZ<Candidate->SurfacePlan->bottomChunkZ
+                ||ChunkZ>Candidate->SurfacePlan->topChunkZ)return false;
+            if(BoundPlan&&BoundPlan!=Candidate)return false;
+            BoundPlan=Candidate;
         }
         if(bNativeOnly)
         {
@@ -4088,8 +4295,8 @@ public:
                 ||BMaxY>NativeOnlyMaximum.Y||BMax>NativeOnlyMaximum.Z)
             {RecordNativeOnlyViolation();return false;}
         }
-        if(bNativeOnly&&!Plan)RecordNativeOnlyViolation();
-        return Plan!=nullptr;
+        if(bNativeOnly&&!BoundPlan)RecordNativeOnlyViolation();
+        return BoundPlan!=nullptr;
     }
 
     FBoxClassification ClassifyBoxDetailed(const FIntVector& Origin,int32 Step,int32 Cells,
@@ -4104,31 +4311,39 @@ public:
         int32 BMax[3]={Origin.X+(Cells+1)*Step,Origin.Y+(Cells+1)*Step,Origin.Z+(Cells+1)*Step};
         const VoxelForgeCore::WorldAssemblyStratumPlanV1* SurfacePlan=nullptr;
         const VoxelForgeCore::WorldAssemblyFloatingIslandPlanV1* IslandPlan=nullptr;
+        const FSurfaceWorldFieldAdapter* SurfaceField=nullptr;
+        const FFloatingIslandFieldAdapter* IslandField=nullptr;
         bool bSurfaceOverlap=false,bIslandOverlap=false,bOtherStrateOverlap=false;
         bool bIslandOtherStrateOverlap=false,bBadPlan=false;
-        if(Owner&&Owner->Manager&&ResolvedLayout)
+        if(Owner&&ResolvedLayout)
         {
             const float LayoutWidth=static_cast<float>(GetResolvedLayoutChunkWidthVoxels());
             const int32 FirstChunk=FMath::FloorToInt(static_cast<float>(BMin[2])/LayoutWidth);
             const int32 LastChunk=FMath::FloorToInt(static_cast<float>(BMax[2])/LayoutWidth);
             for(int32 ChunkZ=FirstChunk;ChunkZ<=LastChunk;++ChunkZ)
             {
-                const ECaveGeneratorType Type=Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ));
-                const int32 StrateIndex=Owner->Manager->GetStrateIndex(static_cast<float>(
-                    (static_cast<double>(ChunkZ)+0.5)*ResolvedLayout->strateLayoutChunkSizeMicrometres/10000.0));
-                if(Type==ECaveGeneratorType::SurfaceWorld)
+                const FBoundStratumField* Bound=FindBoundStratumForChunk(ChunkZ);
+                if(Bound&&Bound->Kind==FBoundStratumField::EKind::SurfaceWorld)
                 {
                     bSurfaceOverlap=true;bIslandOtherStrateOverlap=true;
-                    const auto* Candidate=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
-                    if(!Candidate||(SurfacePlan&&SurfacePlan!=Candidate))bBadPlan=true;
+                    const auto* Candidate=Bound->SurfacePlan;
+                    if(!Candidate||ChunkZ<Candidate->bottomChunkZ
+                        ||ChunkZ>Candidate->topChunkZ
+                        ||(SurfacePlan&&SurfacePlan!=Candidate))bBadPlan=true;
                     SurfacePlan=Candidate;
+                    SurfaceField=std::get_if<FSurfaceWorldFieldAdapter>(
+                        &Bound->Evaluator);
                 }
-                else if(Type==ECaveGeneratorType::FloatingIslands)
+                else if(Bound&&Bound->Kind==FBoundStratumField::EKind::FloatingIslands)
                 {
                     bIslandOverlap=true;bOtherStrateOverlap=true;
-                    const auto* Candidate=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
-                    if(!Candidate||(IslandPlan&&IslandPlan!=Candidate))bBadPlan=true;
+                    const auto* Candidate=Bound->IslandPlan;
+                    if(!Candidate||ChunkZ<Candidate->bottomChunkZ
+                        ||ChunkZ>Candidate->topChunkZ
+                        ||(IslandPlan&&IslandPlan!=Candidate))bBadPlan=true;
                     IslandPlan=Candidate;
+                    IslandField=std::get_if<FFloatingIslandFieldAdapter>(
+                        &Bound->Evaluator);
                 }
                 else
                 {bOtherStrateOverlap=true;bIslandOtherStrateOverlap=true;}
@@ -4213,12 +4428,12 @@ public:
         }
         if(bSurfaceOverlap)
         {
-            if(!WorldAssembly||!SurfacePlan)return Finish(EVoxelTileClass::Mixed,true);
-            const VoxelForgeCore::Heightfield2D Block(WorldAssembly->recipe,*SurfacePlan);
+            if(!WorldAssembly||!SurfacePlan||!SurfaceField)
+                return Finish(EVoxelTileClass::Mixed,true);
             // classifyLatticeBox takes the exact extrema of ground/cap columns at every
             // MC lattice XY in this box. Since density is min(z-ground, cap-z), those extrema
             // bound every lattice sample in Z without a noise amplitude guess.
-            const auto Verdict=Block.classifyLatticeBox(
+            const auto Verdict=SurfaceField->Evaluator.classifyLatticeBox(
                 static_cast<int64>(BMin[0])*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel,
                 static_cast<int64>(BMin[1])*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel,
                 static_cast<int64>(BMin[2])*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel,
@@ -4239,7 +4454,7 @@ public:
         }
         if(bIslandOverlap)
         {
-            if(!IslandPlan)return Finish(EVoxelTileClass::Mixed,true);
+            if(!IslandPlan||!IslandField)return Finish(EVoxelTileClass::Mixed,true);
             constexpr std::int64_t Scale=VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
             const std::int64_t Bottom=IslandPlan->manifest.recipe.layoutMinimumZSubvoxels;
             const std::int64_t Top=IslandPlan->manifest.recipe.layoutMaximumZSubvoxels;
@@ -4259,10 +4474,8 @@ public:
                 return Finish((IslandPlan->manifest.recipe.geometryVersion<3
                     ?BoxBottom>=Top-Seal:BoxBottom>Top-Seal)&&BoxTop<=Top
                     ?EVoxelTileClass::AllSolid:EVoxelTileClass::Mixed);
-            const VoxelForgeCore::FloatingIslandFieldV1 Block(
-                IslandPlan->manifest.recipe,IslandPlan->manifest.plan);
-            if(!Block.isValid())return Finish(EVoxelTileClass::Mixed,true);
-            const auto Interval=Block.interval(static_cast<int64>(BMin[0])*Scale,
+            if(!IslandField->Evaluator.isValid())return Finish(EVoxelTileClass::Mixed,true);
+            const auto Interval=IslandField->Evaluator.interval(static_cast<int64>(BMin[0])*Scale,
                 static_cast<int64>(BMin[1])*Scale,static_cast<int64>(BMin[2])*Scale,
                 static_cast<int64>(BMax[0])*Scale,static_cast<int64>(BMax[1])*Scale,
                 static_cast<int64>(BMax[2])*Scale);
@@ -4782,30 +4995,18 @@ private:
 
     bool NativeSurfaceDensityAt(float X,float Y,float Z,float& OutDensity) const
     {
-        if(!bUseNativeManifestFields||!WorldAssembly||!ResolvedLayout||!Owner||!Owner->Manager||!Owner->Generator
-            ||!std::isfinite(X)||!std::isfinite(Y)||!std::isfinite(Z))return false;
+        if(!bUseNativeManifestFields||!WorldAssembly||!ResolvedLayout||!Owner
+            ||!Owner->Manager||!Owner->Generator||!std::isfinite(X)
+            ||!std::isfinite(Y)||!std::isfinite(Z))return false;
         const float LayoutWidth=static_cast<float>(GetResolvedLayoutChunkWidthVoxels());
         if(!(LayoutWidth>0.0f))return false;
         const int32 ChunkZ=FMath::FloorToInt(Z/LayoutWidth);
-        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)+0.5)
-                *ResolvedLayout->strateLayoutChunkSizeMicrometres/10000.0));
-        const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
-        if(!Plan)return false;
-        constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
-        const double MaxVoxel=static_cast<double>(std::numeric_limits<int64>::max())/Scale;
-        if(std::abs(static_cast<double>(X))>MaxVoxel||std::abs(static_cast<double>(Y))>MaxVoxel
-            ||std::abs(static_cast<double>(Z))>MaxVoxel)return false;
-        const auto ToFixed=[](float Value)
-        {return static_cast<int64>(std::llround(static_cast<double>(Value)
-            *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel));};
-        const VoxelForgeCore::Heightfield2D Block(WorldAssembly->recipe,*Plan);
-        if(!Block.isValid())return false;
-        OutDensity=static_cast<float>(Block.point(ToFixed(X),ToFixed(Y),ToFixed(Z)).densitySubvoxels
-            /Scale);
-        return true;
+        const FBoundStratumField* Bound=FindBoundStratumForChunk(ChunkZ);
+        if(!Bound||Bound->Kind!=FBoundStratumField::EKind::SurfaceWorld
+            ||!Bound->SurfacePlan||ChunkZ<Bound->SurfacePlan->bottomChunkZ
+            ||ChunkZ>Bound->SurfacePlan->topChunkZ)return false;
+        const auto* Field=std::get_if<FSurfaceWorldFieldAdapter>(&Bound->Evaluator);
+        return Field&&Field->densityAt(X,Y,Z,OutDensity);
     }
 
     bool NativeFloatingIslandDensityAt(float X,float Y,float Z,float& OutDensity) const
@@ -4818,13 +5019,15 @@ private:
         const double LayoutChunkWidth=GetResolvedLayoutChunkWidthVoxels();
         if(!(LayoutChunkWidth>0.0))return false;
         const int32 ChunkZ=FMath::FloorToInt(Z/static_cast<float>(LayoutChunkWidth));
-        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)+0.5)
-                *ResolvedLayout->strateLayoutChunkSizeMicrometres/10000.0));
-        const auto* Plan=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
-        if(!Plan)return false;
+        const FBoundStratumField* Bound=FindBoundStratumForChunk(ChunkZ);
+        if(!Bound||Bound->Kind!=FBoundStratumField::EKind::FloatingIslands
+            ||!Bound->IslandPlan||ChunkZ<Bound->IslandPlan->bottomChunkZ
+            ||ChunkZ>Bound->IslandPlan->topChunkZ)return false;
+        const int32 StrateIndex=Bound->StrateIndex;
+        const auto* Plan=Bound->IslandPlan;
+        const auto* FieldAdapter=std::get_if<FFloatingIslandFieldAdapter>(
+            &Bound->Evaluator);
+        if(!FieldAdapter||!FieldAdapter->Evaluator.isValid())return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
         constexpr double Maximum=1000000000000.0/Scale;
         if(std::abs(static_cast<double>(X))>Maximum||std::abs(static_cast<double>(Y))>Maximum
@@ -4832,11 +5035,8 @@ private:
         const auto ToFixed=[](float Value)
         {return static_cast<int64>(std::llround(static_cast<double>(Value)
             *VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel));};
-        const VoxelForgeCore::FloatingIslandFieldV1 Field(
-            Plan->manifest.recipe,Plan->manifest.plan);
-        if(!Field.isValid())return false;
         const std::int64_t qx=ToFixed(X),qy=ToFixed(Y),qz=ToFixed(Z);
-        std::int64_t Density=Field.densitySubvoxels(qx,qy,qz);
+        std::int64_t Density=FieldAdapter->densitySubvoxelsAt(qx,qy,qz);
         const std::int64_t NativeDensity=Density;
         // The anchor-root field keeps broad lobes, but its shortest authored noise
         // wavelength is below one metre. Filter that detail only around a FloatingIslands
@@ -4963,7 +5163,7 @@ private:
                     {
                         const std::int64_t weight=(dx==0?2:1)*(dy==0?2:1)*(dz==0?2:1);
                         const std::int64_t sample=(dx==0&&dy==0&&dz==0)?Density:
-                            Field.densitySubvoxels(qx+dx*FilterStep,qy+dy*FilterStep,
+                            FieldAdapter->densitySubvoxelsAt(qx+dx*FilterStep,qy+dy*FilterStep,
                                 qz+dz*FilterStep);
                         weightedSum+=sample*weight;
                     }
@@ -5000,7 +5200,7 @@ private:
                     {
                         std::array<std::int64_t,3> sample{qx,qy,qz};
                         sample[axis]+=sign*fragmentStep;
-                        const std::int64_t neighbor=Field.densitySubvoxels(
+                        const std::int64_t neighbor=FieldAdapter->densitySubvoxelsAt(
                             sample[0],sample[1],sample[2]);
                         if(neighbor<=0)
                         {
@@ -5031,11 +5231,11 @@ private:
             if(!MakeResolvedStratumBounds(static_cast<double>(Bottom)/Scale,
                 static_cast<double>(Top)/Scale,static_cast<double>(Seal)/Scale,Bounds))
                 return false;
-            const FFloatingIslandParams Params=Owner->Manager->GetFloatingIslandParamsForChunk(
-                FIntVector(0,0,ChunkZ));
+            const FFloatingIslandParams* Params=FieldAdapter->legacyBoundaryParamsAt(ChunkZ);
+            if(!Params)return false;
             float InternalDensity=-OutDensity;
             VF_ApplyUpperBoundarySeal(InternalDensity,Z,static_cast<float>(Bounds.TopZ),
-                static_cast<float>(Bounds.SealThickness),Params.BaseDensity);
+                static_cast<float>(Bounds.SealThickness),Params->BaseDensity);
             OutDensity=-InternalDensity;
         }
         else OutDensity=static_cast<float>(static_cast<double>(Density)/Scale);
@@ -5044,12 +5244,16 @@ private:
 
     bool UsesLegacySurfaceField(float X,float Y,float Z) const
     {
-        if(!Owner||!Owner->Manager||!Owner->Generator)return false;
-        const double LayoutChunkWidth=GetResolvedLayoutChunkWidthVoxels();
-        if(!(LayoutChunkWidth>0.0))return false;
-        const FIntVector ChunkCoord(0,0,FMath::FloorToInt(Z/static_cast<float>(LayoutChunkWidth)));
-        return Owner->Manager->GetGeneratorTypeForChunk(ChunkCoord)
-            ==ECaveGeneratorType::SurfaceWorld;
+        const FBoundStratumField* Bound=FindBoundStratumForZ(Z);
+        return Bound&&Bound->Kind==FBoundStratumField::EKind::SurfaceWorld;
+    }
+
+    bool LegacyGeneratorDensityAt(float X,float Y,float Z,float& OutDensity) const
+    {
+        const FBoundStratumField* Bound=FindBoundStratumForZ(Z);
+        const auto* Legacy=Bound?std::get_if<FLegacyGeneratorFieldAdapter>(
+            &Bound->Evaluator):nullptr;
+        return Legacy&&Legacy->densityAt(X,Y,Z,OutDensity);
     }
 
     float LegacySurfaceDensityAt(float X,float Y,float Z) const
@@ -5057,7 +5261,10 @@ private:
         // SurfaceWorld consumes biome overrides, terrain ops, water level and its sky cap in
         // the legacy stack. Reuse that immutable evaluator as an exact temporary bridge.
         // SurfaceWorld lit biomes, ops de terrain, niveau d'eau et plafond; reutiliser ce champ.
-        const float density=ApplyResolvedStrateComposition(Owner->Generator->GetDensityAt(X,Y,Z),X,Y,Z);
+        float density=0.0f;
+        if(!LegacyGeneratorDensityAt(X,Y,Z,density))
+            density=Owner->Generator->GetDensityAt(X,Y,Z);
+        density=ApplyResolvedStrateComposition(density,X,Y,Z);
         return ApplyEditBrushes(density,X,Y,Z);
     }
 
@@ -8378,11 +8585,13 @@ private:
     bool Built=false;
     bool bNativeOnly=false;
     bool bUseNativeManifestFields=false;
+    float BoundManagerLayoutChunkWidthVoxels=0.0f;
     FIntVector NativeOnlyMinimum=FIntVector::ZeroValue;
     FIntVector NativeOnlyMaximum=FIntVector::ZeroValue;
     mutable std::atomic<uint32> NativeOnlyViolations{0};
     bool FarBuilt=false;
     std::vector<std::array<double,2>> ResolvedBoundaryZIntervalsMicrometres;
+    std::vector<FBoundStratumField> BoundStratumFields;
     std::vector<FInterval> LayerRanges;
     std::vector<FLayerField> LayerFields;
     std::vector<FPrimitive> Primitives;