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
2026-10-23 17:15:46 +02:00
1 parent 753cc9c259
commit efa9e89468
@@ -2162,6 +2162,28 @@ recipe/style audits, route support, open-air, strict layout, legacy validators,
 paired-cost results are in
 [`Standalone/Research/WorldAssemblerM3/Linux36/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux36/REPORT.md).

+### 8.50 Immutable field binding — World Assembler M3 L40
+
+`FStandaloneShapeWorld` now keeps a sorted `FBoundStratumField` table built from the resolved layout
+at world construction. Each entry owns a concrete SurfaceWorld, FloatingIslands, or legacy adapter
+in `FGeneratorFieldAdapterV1`, plus the resolved bounds and native plan pointer. The adapters share
+the immutable `densityAt(x,y,z,out)` shape, while `std::variant` keeps dispatch concrete instead of
+adding a virtual call to every density sample. FloatingIslands keeps its original fixed-point entry
+point for sample evaluation and its boundary parameter table is captured when the adapter is bound.
+
+`DensityAt`, native SurfaceWorld/FloatingIslands evaluation, legacy SurfaceWorld bridging and
+`ClassifyBoxDetailed` select from the bound table. The native adapters no longer ask the manager
+which generator or plan to use per sample; box proof reuses the bound field objects. The existing
+float-to-fixed conversion order, density arithmetic and shared boundary composition remain intact.
+The manager's layout-width value is captured once for the legacy-compatible chunk-index projection.
+
+The legacy adapter is still a compatibility bridge: `UVoxelGenerator::GetDensityAt` retains its
+own manager routing when invoked for legacy SurfaceWorld fields or out-of-plan fallback queries.
+Other shared-composition policy branches and passage/boundary planning remain outside this slice.
+No Unreal adapter or `VoxelWorld.cpp` change was needed, and the evaluator version is unchanged.
+L37/L39 owner hashes are the parity baseline; the L40 report records fast, medium, full and paired
+cost evidence.
+
 ## 9. Multiplayer model (listen-server first, dedicated-friendly)

 > **Status: transport is DESIGN ONLY — nothing is networked in-tree yet** (no `Replicated`/`HasAuthority`/RPCs; a
@@ -1268,6 +1268,17 @@ ARCHITECTURE §8.47 and
 `WorldAssemblyEvaluatorVersion=23`. See ARCHITECTURE §8.49 and
 [`Standalone/Research/WorldAssemblerM3/Linux36/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux36/REPORT.md).

+### 3.33 Immutable field binding — World Assembler M3 L40
+
+| Symbol | Canonical file | Role |
+|---|---|---|
+| `FSurfaceWorldFieldAdapter`, `FFloatingIslandFieldAdapter`, `FLegacyGeneratorFieldAdapter`, `FGeneratorFieldAdapterV1` | `Standalone/Core/src/ShapeWorldInternal.h` | Concrete, immutable density adapters with one shared `densityAt(x,y,z,out)` call shape; the variant avoids per-sample virtual dispatch. FI retains its fixed-point entry point and prebound legacy boundary parameters. |
+| `FBoundStratumField`, `BindResolvedStratumFields`, `FindBoundStratumForChunk` | `Standalone/Core/src/ShapeWorldInternal.h` | Bind a resolved strate's plan, evaluator and chunk interval once during world initialization; native field and classification queries select this table. |
+| `NativeSurfaceDensityAt`, `NativeFloatingIslandDensityAt`, `ClassifyBoxDetailed` | `Standalone/Core/src/ShapeWorldInternal.h` | Consume the prebound adapters and plan pointers instead of looking up strate type/parameters through the manager per query. |
+
+Hash parity is unchanged from L37/L39; see ARCHITECTURE §8.50 and
+[`Standalone/Research/WorldAssemblerM3/Linux40/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux40/REPORT.md).
+
 ## 4. The density pipeline (most-edited hot path)

 ### 4.1 `GetDensityWithParams` (TunnelNetwork) — VoxelGenerator.cpp:3749
@@ -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)
+            {
+                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;
@@ -0,0 +1,74 @@
+# Linux40 — immutable field binding
+
+## Change
+
+`ShapeWorldInternal.h` now has concrete immutable SurfaceWorld, FloatingIslands and legacy adapters
+with a common `densityAt(x,y,z,out)` call shape. `FGeneratorFieldAdapterV1` stores them in a variant,
+so hot sampling uses concrete dispatch without a virtual call. FI retains its fixed-point sampler and
+captures the legacy boundary parameters while binding.
+
+`BindResolvedStratumFields` creates a sorted table of resolved strate bounds, plan references and
+evaluator objects during world construction/initialization. Native SurfaceWorld and FI sampling,
+boundary composition lookup, legacy SurfaceWorld bridging and `ClassifyBoxDetailed` select from that
+table. The manager layout width is captured once for the legacy-compatible chunk projection.
+
+## Lookup boundary and identity
+
+The direct manager selection lookups in native SurfaceWorld/FI evaluation and box classification are
+removed. `DensityAt` now selects native fields through the bound table. Legacy
+`UVoxelGenerator::GetDensityAt` still performs its own manager routing when reached through the
+legacy bridge or an out-of-plan fallback. Manager-derived layout width/FI compatibility parameters
+are captured at bind time; manager access also remains in build/planning helpers. Generator-specific
+boundary and passage policy still lives in `FStandaloneShapeWorld`.
+
+No density arithmetic, fixed-point conversion order, evaluator version or Unreal adapter changed.
+The canonical owner FI and SurfaceWorld hashes are identical to L37/L39 for W1 and W12. The owner
+layout IDs also match L39: FI `b7a7d9ecc48d8f26`, SurfaceWorld `8a52e84c26ed92d2`. Fast logs and hash
+summaries: `Saved/Linux/l40/fast-trial1.log` and `Saved/Linux/l40/fast-summary.json`.
+
+## Cost
+
+Five interleaved pairs against the L39 Clang binary, using the canonical owner recipes:
+
+| Recipe | L39 median | L40 median | Median change | Paired changes (L40 vs L39) |
+|---|---:|---:|---:|---|
+| FloatingIslands | 17.556 s | 17.440 s | −0.66% | +2.26%, −3.99%, −0.66%, −0.87%, −0.47% |
+| SurfaceWorld | 1.829 s | 1.805 s | −1.31% | −2.64%, −0.22%, +0.55%, −0.44%, −1.48% |
+
+Both deltas are within observed pair noise; no per-voxel regression was measured. Raw output is in
+`Saved/Linux/l40/cost-l40-vs-l39-run.log` and `cost-l40-vs-l39-summary.json`.
+
+## Verification
+
+| Tier | Result | Wall time | Evidence |
+|---|---|---:|---|
+| Fast | PASS | 162.0 s | Canonical owner hashes match L37 for both recipes at W1/W12; all controls pass. |
+| Medium | PASS | 468.6 s | Transition, route/proof, LOD0–8 ring, owner shape and capture matrix pass. |
+| Full | TIMED OUT | 1740 s (29 min) | GCC build and supplement passed; L25 and crossing24 determinism passed for both compilers, and Clang upper-SW style0 W1/W8/W12 passed. The run timed out during the GCC upper-SW style0 W1 cell; no full summary or cost-baseline/pair results were produced. |
+
+Clang and GCC candidate builds succeeded with source stamp
+`f35bc59c6172370e98dc83ec8ee5ba51dfab83a3faf075c26189fc83172f4ac8`. The full run used the requested
+CPU/memory limits and a 1740-second timeout. At the stop, host load was 20.5. The partial log is
+`Saved/Linux/l40/full-final.log`; a `full-summary.json` was not written. Other tier and build logs are
+under `Saved/Linux/l40/`.
+
+## Failed attempts
+
+- The first Clang build passed `unique_ptr` objects to adapter constructors expecting raw observer
+  pointers; corrected with `.get()`, then the build passed.
+- Two early cost-harness launches failed before starting measurements: one shell quoting error and
+  two Python `-c` quoting errors. The later logged five-pair run completed successfully.
+- The single full-tier run reached its 1740-second timeout while the GCC upper-SW fixture style0 W1
+  determinism cell was still running. The cell has no completion record; the run returned timeout
+  status 124. No full-tier L36 baseline build or full-tier cost pairs ran.
+
+No Unreal compile was run; no Unreal adapter or `VoxelWorld.cpp` source change was required.
+
+## Orchestrator review (Claude)
+
+Accepted. The full tier had timed out here under load (two Lunas plus host load of about 20). I re-ran it alone on
+the final source (stamp `f35bc59c…`): **PASS, 407 gates, 2857 s.** Its built-in cost comparison is against
+**L36** and shows FI +3.03% (all five pairs positive) and SW +0.38%. That FI delta is L37's mouth geometry; this
+round's own L39→L40 pairs are −0.66% FI and −1.31% SW. Two follow-ups for the tool:
+- the full tier's cost baseline is hard-coded to L36; it should follow the previous commit;
+- the full tier now needs about 48 minutes including builds, so its timeout must be above 29 minutes.
@@ -0,0 +1,45 @@
+# Research 7 — terrain disk cache: Windows and multiplayer
+
+Inspection date: 2026-10-23. Read-only review of `Standalone/Source/StreamingWorld.h`, `Standalone/Source/StandaloneViewer.cpp`, Core version declarations, and the verification README.
+
+## What exists and Windows blockers
+
+`FStandaloneMeshCache` is a whole-world archive, not an on-demand disk cache. Its filename is derived from seed, clip radius, and tunnel mode; the header also checks source JSON FNV-1a-64, generation settings, cache/algorithm version, tunnel mode, and voxel size. A tile lookup uses `(LOD, X, Y, Z)`. The `VFMESH1\0` v1 archive has an 80-byte raw C++ header, 40-byte raw tile records, float32 position/normal pairs, and uint32 indices. It is uncompressed and host-layout/endian dependent; the endian marker detects mismatch but does not convert fields. Save/load also omit generated `SurfaceVertexCount`, `SkirtTriangleCount`, and `TriangleSkirtFaceMasks`, so a cache hit cannot preserve skirt culling.
+
+Load reads and validates the entire archive synchronously in `ConfigureProfile` before workers start. Streaming workers then copy hits from an immutable in-memory map. Bake save writes synchronously to the final path with truncation. There is no disk eviction or file lock; leaving tiles evicts resident meshes only. The cache has no `mmap`, `fsync`, rename, or zlib use today. Existing checks reject mismatched metadata, invalid LOD/counts, truncated data, duplicate keys, non-finite positions/normals, and out-of-range indices, but there is no payload checksum, total allocation budget, or trailing-data check. Stored density hashes are not checked against the mesh.
+
+Windows concerns are the narrow `.string()` path conversion and a fixed `MAX_PATH` buffer in `DefaultDataPath`; the cache is written next to source data, which may be read-only in a packaged install. Windows long-path support needs application opt-in, and the cache path should stay in TCHAR/UE paths. Direct-to-final truncation can leave a partial archive and destroy the previous one; `ofstream::flush` is not a durable or atomic replacement. Concurrent bakes can collide. The standalone viewer itself has unguarded Win32/D3D11 headers and should not be pulled into the UE plugin; keep any platform adapter gated and use UE file APIs.
+
+## UE5 design
+
+- Store a versioned, endian-neutral per-tile payload under `FPaths::ProjectSavedDir()/VoxelForge/TileCache/<project-id>/<user-scope>/`. Use `ProjectPersistentDownloadDir()` when the packaged install’s Saved directory is not writable; append a project identity either way. [FPaths API](https://dev.epicgames.com/documentation/en-us/unreal-engine/API/Runtime/Core/FPaths)
+- Use `FPlatformFileManager::Get().GetPlatformFile().OpenAsyncRead()` and `IAsyncReadFileHandle::ReadRequest()` for tile/block reads. Parse and decompress on a worker; never wait for file I/O or decompression on the game thread. UE documents async open as non-blocking and read requests as caller-owned; keep buffers/requests alive through completion and cancellation. [FPlatformFileManager](https://dev.epicgames.com/documentation/unreal-engine/API/Runtime/Core/FPlatformFileManager), [IPlatformFile](https://dev.epicgames.com/documentation/unreal-engine/API/Runtime/Core/IPlatformFile), [ReadRequest](https://dev.epicgames.com/documentation/unreal-engine/API/Runtime/Core/Async/IAsyncReadFileHandle/ReadRequest?application_version=5.5)
+- Use UE `FCompression` with registered format names and `IsFormatValid`; its compression/decompression routines are thread-safe. This avoids a separately linked Windows zlib. Keep codec ID/version in each tile record and check availability in the packaged client/server. Oodle Data is supplied as a UE plugin and documents Kraken, Mermaid, and Selkie as distinct size/decode-speed choices; do not assume a packaging setting alone enables a runtime cache codec. [FCompression](https://dev.epicgames.com/documentation/en-us/unreal-engine/API/Runtime/Core/FCompression), [Oodle Data (UE 5.7)](https://dev.epicgames.com/documentation/en-us/unreal-engine/oodle-data?application_version=5.7)
+- Treat the generated terrain as persisted feature data, not as a speed claim. Record schema, world key, tile key, codec, compressed/uncompressed sizes, and payload digest. Include all mesh groups, masks, and collision inputs required to rebuild identical tiles. Write a unique temp beside the target, flush and close it, then replace/rename on the same volume. Do not allow a cross-volume copy fallback. Use `ReplaceFileW`/same-volume `MoveFileExW` through a Windows adapter; `FlushFileBuffers` is the file-data durability step. [ReplaceFileW](https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-replacefilew), [MoveFileExW](https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-movefileexw), [FlushFileBuffers](https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-flushfilebuffers), [Windows long paths](https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation)
+
+Cache misses, corrupt entries, and unavailable codecs fall back to cold generation on workers. Keep eviction as a background size-bounded LRU; cache eviction only causes regeneration. Continue judging the no-cache cold path separately.
+
+## Key, multiplayer, invalidation, validation
+
+Key a base tile by authoritative season/world-plan identity (include Core recipe and plan content hashes), recipe/schema version, evaluator version, selected mesher plus an explicit mesher implementation revision, LOD and absolute tile coordinate. Add the development source stamp and cache-format version. Core currently declares WorldAssembly schema 2/evaluator 208; FloatingIsland recipe schema 1/default geometry version 4; mesher choices are MarchingCubesV1, HybridV1, HybridV2, with far-horizon version 4 affecting LOD4–8. Read actual resolved recipe/plan versions and hashes from the active snapshot. The verification README defines a SHA-256 source stamp over a sorted source manifest; it is dynamic and can optionally include the Unreal adapter. The current cache uses only the source-data FNV hash and does not carry that stamp.
+
+Persist immutable base terrain only. Keep player edits in the replicated diff layer and overlay them at runtime. Do not write edited composite tiles into the base cache; if a separate composite cache is ever added, key it by the affected tile’s edit revision/content hash. A client cache is visual convenience only: the server uses its own matching cache or regenerates and builds its own collision; never accept client cache bytes as collision or gameplay authority.
+
+On load, bound both per-record and total tile/byte allocations before allocating; require exact file/block lengths, known codec/schema/key, finite and bounded geometry, valid normals, triangle/index/mask counts, and index ranges. Verify a per-payload digest and regenerate on failure. A digest detects accidental corruption, not a malicious rewrite that also changes the digest; only importable/shared caches need a server signature or MAC. Never trust a cache supplied by a client.
+
+## Compression probe and next build round
+
+A small serial Python probe used `VFMSH001` exports `linux27-fi-anchor-pillar.vfmesh` and `linux27-sw-column-wide.vfmesh`, all non-empty tiles LOD0–8, CPython zlib level 1. Payload excludes scene/tile headers. These are Linux in-memory decode numbers, not UE/MSVC or disk-I/O results; exports lack recipe/source stamps and density samples.
+
+| Export | Non-empty tiles | Mean raw → zlib bytes/tile | Payload ratio | Decode ms/tile p50 / p95 |
+|---|---:|---:|---:|---:|
+| FI | 1,380 | 75.6 KB → 24.2 KB | 32.0% | 0.109 / 0.523 |
+| SW | 1,416 | 60.0 KB → 21.5 KB | 35.8% | 0.114 / 0.459 |
+
+The serial probe peak RSS was 15.4 MiB. Per-LOD details are in `Saved/Linux/research/R7_python_zlib_probe.json`; script: `Saved/Linux/research/R7_python_zlib_probe.py`.
+
+Later compare none, zlib, Oodle Kraken/Mermaid/Selkie, and LZ4; quantized vertices (uint16 positions, compact normals) with delta indices; and density/sign-bit packing with RLE. Use the same owner FI and SW tile sets at LOD0–8, keyed to the exact active recipe/plan. Record bytes/tile (median/p95/total), single-core decode ms/tile (median/p95), peak working memory, and cold disk-read-plus-decode latency separately. Validate geometry error, seams, and server collision against uncompressed output. Sign-bit inputs are absent from these mesh exports, so that candidate needs a later density export and must include remesh time in its comparison.
+
+## Owner question
+
+Will cache files remain local to each user/install, or be copied/shared between machines?
@@ -0,0 +1,255 @@
+{
+  "codec": "CPython zlib level 1",
+  "decode_repeats_per_tile": 3,
+  "files": {
+    "FI": {
+      "path": "Saved/Linux/linux27-fi-anchor-pillar.vfmesh",
+      "file_bytes": 104373453,
+      "scene_version": 1,
+      "voxel_size_microns": 250000,
+      "tile_records": 2482,
+      "nonempty_tile_records": 1380,
+      "raw_payload_bytes": 104284041,
+      "zlib_payload_bytes": 33400206,
+      "weighted_ratio_pct": 32.02810869210563,
+      "raw_bytes_per_nonempty_tile_median": 46104.0,
+      "decode_ms_per_tile_median": 0.109374,
+      "decode_ms_per_tile_p95": 0.523225,
+      "lod": {
+        "0": {
+          "nonempty_tiles": 136,
+          "raw_bytes_total": 11914151,
+          "packed_bytes_total": 3218452,
+          "weighted_ratio_pct": 27.01369153370643,
+          "raw_bytes_median": 95849.5,
+          "packed_bytes_median": 33744.0,
+          "decode_ms_median": 0.27110500000000004,
+          "decode_ms_p95": 0.316059,
+          "encode_ms_median": 0.610732,
+          "encode_ms_p95": 0.837242
+        },
+        "1": {
+          "nonempty_tiles": 131,
+          "raw_bytes_total": 16499945,
+          "packed_bytes_total": 5941348,
+          "weighted_ratio_pct": 36.008289724602115,
+          "raw_bytes_median": 92598,
+          "packed_bytes_median": 42032,
+          "decode_ms_median": 0.317582,
+          "decode_ms_p95": 0.818547,
+          "encode_ms_median": 0.837591,
+          "encode_ms_p95": 2.246851
+        },
+        "2": {
+          "nonempty_tiles": 172,
+          "raw_bytes_total": 6666423,
+          "packed_bytes_total": 2031078,
+          "weighted_ratio_pct": 30.467283579214822,
+          "raw_bytes_median": 45768.0,
+          "packed_bytes_median": 11943.0,
+          "decode_ms_median": 0.102419,
+          "decode_ms_p95": 0.124572,
+          "encode_ms_median": 0.2224085,
+          "encode_ms_p95": 0.256617
+        },
+        "3": {
+          "nonempty_tiles": 125,
+          "raw_bytes_total": 5555529,
+          "packed_bytes_total": 1649468,
+          "weighted_ratio_pct": 29.6905659209051,
+          "raw_bytes_median": 45768,
+          "packed_bytes_median": 11960,
+          "decode_ms_median": 0.104118,
+          "decode_ms_p95": 0.168216,
+          "encode_ms_median": 0.2313,
+          "encode_ms_p95": 0.349597
+        },
+        "4": {
+          "nonempty_tiles": 174,
+          "raw_bytes_total": 9645483,
+          "packed_bytes_total": 3115498,
+          "weighted_ratio_pct": 32.30007247952228,
+          "raw_bytes_median": 45768.0,
+          "packed_bytes_median": 13419.0,
+          "decode_ms_median": 0.1148265,
+          "decode_ms_p95": 0.259002,
+          "encode_ms_median": 0.255053,
+          "encode_ms_p95": 0.641356
+        },
+        "5": {
+          "nonempty_tiles": 144,
+          "raw_bytes_total": 4232303,
+          "packed_bytes_total": 1383894,
+          "weighted_ratio_pct": 32.69836776809222,
+          "raw_bytes_median": 24938.0,
+          "packed_bytes_median": 9315.0,
+          "decode_ms_median": 0.06914100000000001,
+          "decode_ms_p95": 0.178538,
+          "encode_ms_median": 0.1752125,
+          "encode_ms_p95": 0.460837
+        },
+        "6": {
+          "nonempty_tiles": 96,
+          "raw_bytes_total": 5255938,
+          "packed_bytes_total": 1770019,
+          "weighted_ratio_pct": 33.67655782849798,
+          "raw_bytes_median": 38395.0,
+          "packed_bytes_median": 10093.5,
+          "decode_ms_median": 0.088979,
+          "decode_ms_p95": 0.317363,
+          "encode_ms_median": 0.1975715,
+          "encode_ms_p95": 0.823547
+        },
+        "7": {
+          "nonempty_tiles": 96,
+          "raw_bytes_total": 11085771,
+          "packed_bytes_total": 3715174,
+          "weighted_ratio_pct": 33.51299607397627,
+          "raw_bytes_median": 105285.5,
+          "packed_bytes_median": 30236.0,
+          "decode_ms_median": 0.271746,
+          "decode_ms_p95": 0.588424,
+          "encode_ms_median": 0.63578,
+          "encode_ms_p95": 1.607345
+        },
+        "8": {
+          "nonempty_tiles": 306,
+          "raw_bytes_total": 33428498,
+          "packed_bytes_total": 10575275,
+          "weighted_ratio_pct": 31.635507524149006,
+          "raw_bytes_median": 100540.0,
+          "packed_bytes_median": 29556.0,
+          "decode_ms_median": 0.258287,
+          "decode_ms_p95": 0.529198,
+          "encode_ms_median": 0.644282,
+          "encode_ms_p95": 1.330977
+        }
+      }
+    },
+    "SW": {
+      "path": "Saved/Linux/linux27-sw-column-wide.vfmesh",
+      "file_bytes": 85051310,
+      "scene_version": 1,
+      "voxel_size_microns": 250000,
+      "tile_records": 2130,
+      "nonempty_tile_records": 1416,
+      "raw_payload_bytes": 84974570,
+      "zlib_payload_bytes": 30390177,
+      "weighted_ratio_pct": 35.76384911391726,
+      "raw_bytes_per_nonempty_tile_median": 38620.5,
+      "decode_ms_per_tile_median": 0.11431150000000001,
+      "decode_ms_per_tile_p95": 0.459004,
+      "lod": {
+        "0": {
+          "nonempty_tiles": 285,
+          "raw_bytes_total": 22447321,
+          "packed_bytes_total": 9051898,
+          "weighted_ratio_pct": 40.32507041708897,
+          "raw_bytes_median": 79066,
+          "packed_bytes_median": 32524,
+          "decode_ms_median": 0.244825,
+          "decode_ms_p95": 0.389183,
+          "encode_ms_median": 0.65028,
+          "encode_ms_p95": 1.155402
+        },
+        "1": {
+          "nonempty_tiles": 149,
+          "raw_bytes_total": 14395111,
+          "packed_bytes_total": 5813866,
+          "weighted_ratio_pct": 40.38778165725849,
+          "raw_bytes_median": 108155,
+          "packed_bytes_median": 46017,
+          "decode_ms_median": 0.348557,
+          "decode_ms_p95": 0.551613,
+          "encode_ms_median": 0.930073,
+          "encode_ms_p95": 1.662883
+        },
+        "2": {
+          "nonempty_tiles": 217,
+          "raw_bytes_total": 6043511,
+          "packed_bytes_total": 1736514,
+          "weighted_ratio_pct": 28.733529234909973,
+          "raw_bytes_median": 27184,
+          "packed_bytes_median": 6351,
+          "decode_ms_median": 0.058163,
+          "decode_ms_p95": 0.14959,
+          "encode_ms_median": 0.14067,
+          "encode_ms_p95": 0.37157
+        },
+        "3": {
+          "nonempty_tiles": 190,
+          "raw_bytes_total": 6058525,
+          "packed_bytes_total": 1902018,
+          "weighted_ratio_pct": 31.394076941169676,
+          "raw_bytes_median": 35120.0,
+          "packed_bytes_median": 7724.5,
+          "decode_ms_median": 0.0678105,
+          "decode_ms_p95": 0.15743,
+          "encode_ms_median": 0.17532,
+          "encode_ms_p95": 0.392782
+        },
+        "4": {
+          "nonempty_tiles": 173,
+          "raw_bytes_total": 8837946,
+          "packed_bytes_total": 2824214,
+          "weighted_ratio_pct": 31.95554713730996,
+          "raw_bytes_median": 35120,
+          "packed_bytes_median": 13578,
+          "decode_ms_median": 0.106095,
+          "decode_ms_p95": 0.267514,
+          "encode_ms_median": 0.252394,
+          "encode_ms_p95": 0.663049
+        },
+        "5": {
+          "nonempty_tiles": 144,
+          "raw_bytes_total": 6093522,
+          "packed_bytes_total": 1982234,
+          "weighted_ratio_pct": 32.530185334524106,
+          "raw_bytes_median": 35013.0,
+          "packed_bytes_median": 10745.0,
+          "decode_ms_median": 0.08670549999999999,
+          "decode_ms_p95": 0.186559,
+          "encode_ms_median": 0.230201,
+          "encode_ms_p95": 0.474221
+        },
+        "6": {
+          "nonempty_tiles": 96,
+          "raw_bytes_total": 6363816,
+          "packed_bytes_total": 2057514,
+          "weighted_ratio_pct": 32.33145018649188,
+          "raw_bytes_median": 61690.0,
+          "packed_bytes_median": 18087.0,
+          "decode_ms_median": 0.1538235,
+          "decode_ms_p95": 0.308712,
+          "encode_ms_median": 0.394647,
+          "encode_ms_p95": 0.820557
+        },
+        "7": {
+          "nonempty_tiles": 96,
+          "raw_bytes_total": 9716690,
+          "packed_bytes_total": 3399953,
+          "weighted_ratio_pct": 34.99085593962553,
+          "raw_bytes_median": 98110.0,
+          "packed_bytes_median": 30712.0,
+          "decode_ms_median": 0.2564655,
+          "decode_ms_p95": 0.53338,
+          "encode_ms_median": 0.6491285,
+          "encode_ms_p95": 1.50398
+        },
+        "8": {
+          "nonempty_tiles": 66,
+          "raw_bytes_total": 5018128,
+          "packed_bytes_total": 1621966,
+          "weighted_ratio_pct": 32.322132875048226,
+          "raw_bytes_median": 74425.0,
+          "packed_bytes_median": 23710.5,
+          "decode_ms_median": 0.187504,
+          "decode_ms_p95": 0.337573,
+          "encode_ms_median": 0.47401950000000004,
+          "encode_ms_p95": 0.885023
+        }
+      }
+    }
+  },
+  "process_peak_rss_kib": 15772
+}
@@ -0,0 +1,123 @@
+#!/usr/bin/env python3
+"""Cheap per-tile zlib probe over existing VFMSH001 scenes; read-only inputs."""
+import collections
+import json
+import os
+import resource
+import statistics
+import struct
+import sys
+import time
+import zlib
+from pathlib import Path
+
+FILES = {
+    "FI": Path("Saved/Linux/linux27-fi-anchor-pillar.vfmesh"),
+    "SW": Path("Saved/Linux/linux27-sw-column-wide.vfmesh"),
+}
+REPEATS = 3
+
+def percentile(values, fraction):
+    ordered = sorted(values)
+    if not ordered:
+        return None
+    return ordered[min(len(ordered) - 1, int((len(ordered) - 1) * fraction))]
+
+def scan(path):
+    rows = collections.defaultdict(list)
+    with path.open("rb") as stream:
+        prefix = stream.read(60)
+        if len(prefix) != 60 or prefix[:8] != b"VFMSH001":
+            raise RuntimeError(f"{path}: not a VFMSH001 scene")
+        version, voxel_um, tile_count = struct.unpack_from("<3I", prefix, 8)
+        if version != 1 or tile_count > 1_000_000:
+            raise RuntimeError(f"{path}: unsupported header")
+        for _ in range(tile_count):
+            header = stream.read(36)
+            if len(header) != 36:
+                raise EOFError(f"{path}: truncated record")
+            key = struct.unpack_from("<4i", header)
+            _, _, vertex_count, index_count, mask_count = struct.unpack_from("<5I", header, 16)
+            if key[3] < 0 or key[3] > 8 or index_count % 3:
+                raise RuntimeError(f"{path}: malformed tile record")
+            raw_size = vertex_count * 24 + index_count * 4 + mask_count
+            payload = stream.read(raw_size)
+            if len(payload) != raw_size:
+                raise EOFError(f"{path}: truncated tile payload")
+            if raw_size == 0:
+                continue
+            encode_start = time.perf_counter_ns()
+            packed = zlib.compress(payload, level=1)
+            encode_ms = (time.perf_counter_ns() - encode_start) / 1_000_000.0
+            decode_ms = []
+            for _ in range(REPEATS):
+                start = time.perf_counter_ns()
+                decoded = zlib.decompress(packed)
+                decode_ms.append((time.perf_counter_ns() - start) / 1_000_000.0)
+                if decoded != payload:
+                    raise RuntimeError(f"{path}: round-trip mismatch")
+            rows[key[3]].append({
+                "raw": raw_size, "packed": len(packed),
+                "encode_ms": encode_ms, "decode_ms": statistics.median(decode_ms),
+                "vertices": vertex_count, "indices": index_count,
+            })
+        if stream.read(1):
+            raise RuntimeError(f"{path}: trailing data")
+    return version, voxel_um, tile_count, rows
+
+def main():
+    if hasattr(os, "sched_getaffinity"):
+        os.sched_setaffinity(0, {min(os.sched_getaffinity(0))})
+    result = {"codec": "CPython zlib level 1", "decode_repeats_per_tile": REPEATS, "files": {}}
+    for name, path in FILES.items():
+        version, voxel_um, tile_count, by_lod = scan(path)
+        lod_result = {}
+        for lod, rows in sorted(by_lod.items()):
+            raw = [r["raw"] for r in rows]
+            packed = [r["packed"] for r in rows]
+            dec = [r["decode_ms"] for r in rows]
+            enc = [r["encode_ms"] for r in rows]
+            lod_result[str(lod)] = {
+                "nonempty_tiles": len(rows),
+                "raw_bytes_total": sum(raw),
+                "packed_bytes_total": sum(packed),
+                "weighted_ratio_pct": 100.0 * sum(packed) / sum(raw),
+                "raw_bytes_median": statistics.median(raw),
+                "packed_bytes_median": statistics.median(packed),
+                "decode_ms_median": statistics.median(dec),
+                "decode_ms_p95": percentile(dec, 0.95),
+                "encode_ms_median": statistics.median(enc),
+                "encode_ms_p95": percentile(enc, 0.95),
+            }
+        total_raw = sum(x["raw_bytes_total"] for x in lod_result.values())
+        total_packed = sum(x["packed_bytes_total"] for x in lod_result.values())
+        all_decode = [r["decode_ms"] for rows in by_lod.values() for r in rows]
+        all_raw = [r["raw"] for rows in by_lod.values() for r in rows]
+        result["files"][name] = {
+            "path": str(path), "file_bytes": path.stat().st_size,
+            "scene_version": version, "voxel_size_microns": voxel_um,
+            "tile_records": tile_count, "nonempty_tile_records": sum(len(v) for v in by_lod.values()),
+            "raw_payload_bytes": total_raw, "zlib_payload_bytes": total_packed,
+            "weighted_ratio_pct": 100.0 * total_packed / total_raw,
+            "raw_bytes_per_nonempty_tile_median": statistics.median(all_raw),
+            "decode_ms_per_tile_median": statistics.median(all_decode),
+            "decode_ms_per_tile_p95": percentile(all_decode, 0.95),
+            "lod": lod_result,
+        }
+    result["process_peak_rss_kib"] = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
+    out = Path("Saved/Linux/research/R7_python_zlib_probe.json")
+    out.write_text(json.dumps(result, indent=2) + "\n", encoding="utf-8")
+    for name, info in result["files"].items():
+        print(f"{name}: tiles={info['nonempty_tile_records']}/{info['tile_records']} "
+              f"raw={info['raw_payload_bytes']} packed={info['zlib_payload_bytes']} "
+              f"ratio={info['weighted_ratio_pct']:.1f}% "
+              f"decode_p50/p95={info['decode_ms_per_tile_median']:.3f}/"
+              f"{info['decode_ms_per_tile_p95']:.3f}ms")
+        print("  LOD raw B/tile median | zlib B/tile median | decode p50/p95 ms")
+        for lod, row in info["lod"].items():
+            print(f"  {lod}: {row['raw_bytes_median']:.0f} | {row['packed_bytes_median']:.0f} | "
+                  f"{row['decode_ms_median']:.3f}/{row['decode_ms_p95']:.3f}")
+    print(f"peak_rss={result['process_peak_rss_kib']} KiB; JSON={out}")
+
+if __name__ == "__main__":
+    main()
@@ -0,0 +1,2 @@
+# Shared notes (researcher R7 <-> implementer L40), newest at bottom
+
				`@@ -0,0 +1,2 @@`
				`# Shared notes (researcher R7 <-> implementer L40), newest at bottom`