diag: passage source-floor clamp rejected (L91); field has steep non-distance tails

Clamping the passage-composition source density at -c (c=2..6 voxels, diagnostic, default off)
changes the surface far beyond the bar: c=6 still 65 sign flips, up to 165 cm displacement, 120 deg
normal change (downstream composition consumes deep values). Source gradient at crossings is
distance-like at the median but has huge tails (FI p90 |grad| 512, max 894 vox/vox), so the
density-dependent passage reach is inflated by non-distance values. No world change.

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

Standalone/Source/StreamBenchmarkPipeline.h

@@ -132,6 +132,426 @@ namespace StandaloneStreamBenchmark
         return Result;
     }
 
+    struct FPassageClampComparison
+    {
+        std::uint64_t samples=0,changedSamples=0,signFlips=0;
+        std::uint64_t crossingEdgeMismatches=0,sharedCrossingEdges=0,movedCrossingEdges=0;
+        std::uint64_t normalVertices=0,normalPairingFailures=0,changedNormalVertices=0;
+        double maxAbsDensityDelta=0.0,maxSurfaceDisplacementCm=0.0;
+        double sumSurfaceDisplacementCm=0.0,maxNormalAngleDegrees=0.0;
+        double sumNormalAngleDegrees=0.0;
+        std::array<std::uint64_t,4> movedEdgeRegions{},normalVertexRegions{};
+        bool meshChanged=false,valid=false;
+    };
+
+    struct FPassageRegion
+    {
+        int category=3; // 0 wall, 1 floor, 2 mouth, 3 outside the passage envelope
+        double signedWallDistanceVoxels=std::numeric_limits<double>::infinity();
+    };
+
+    inline FPassageRegion ClassifyPassageRegion(
+        const VoxelForgeCore::ResolvedLayoutSnapshotV3* Layout,
+        const std::array<double,3>& PositionVoxels)
+    {
+        FPassageRegion best;
+        if(!Layout)return best;
+        constexpr double Q=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
+        double bestAbsoluteWallDistance=std::numeric_limits<double>::infinity();
+        for(const auto& passage:Layout->passages)
+        {
+            if(passage.controlPoints.size()<2)continue;
+            for(std::size_t index=0;index+1<passage.controlPoints.size();++index)
+            {
+                const auto& a=passage.controlPoints[index];
+                const auto& b=passage.controlPoints[index+1];
+                std::array<double,3> delta{},fromA{};
+                double lengthSquared=0.0,dot=0.0;
+                for(std::size_t axis=0;axis<3;++axis)
+                {
+                    delta[axis]=(static_cast<double>(b.positionSubvoxels[axis])
+                        -a.positionSubvoxels[axis])/Q;
+                    fromA[axis]=PositionVoxels[axis]
+                        -static_cast<double>(a.positionSubvoxels[axis])/Q;
+                    lengthSquared+=delta[axis]*delta[axis];
+                    dot+=fromA[axis]*delta[axis];
+                }
+                const double t=lengthSquared>0.0
+                    ?std::clamp(dot/lengthSquared,0.0,1.0):0.0;
+                double distanceSquared=0.0;
+                for(std::size_t axis=0;axis<3;++axis)
+                {
+                    const double difference=fromA[axis]-t*delta[axis];
+                    distanceSquared+=difference*difference;
+                }
+                const double radius=(static_cast<double>(a.radiusSubvoxels)+t*(
+                    static_cast<double>(b.radiusSubvoxels)-a.radiusSubvoxels))/Q;
+                const double signedWallDistance=std::sqrt(distanceSquared)-radius;
+                if(std::abs(signedWallDistance)>=bestAbsoluteWallDistance)continue;
+                bestAbsoluteWallDistance=std::abs(signedWallDistance);
+                best.signedWallDistanceVoxels=signedWallDistance;
+                const bool endpointSegment=index<8
+                    ||index+9>=passage.controlPoints.size();
+                if(endpointSegment)
+                    best.category=2;
+                else
+                {
+                    const double vertical=fromA[2]-t*delta[2];
+                    best.category=radius>0.0&&vertical<-0.55*radius?1:0;
+                }
+            }
+        }
+        if(best.signedWallDistanceVoxels>48.0)best.category=3;
+        return best;
+    }
+
+    inline FPassageClampComparison ComparePassageClampMeshes(
+        const VoxelForgeCore::TileMesh& Base,const VoxelForgeCore::TileMesh& Candidate,
+        const VoxelForgeCore::ResolvedLayoutSnapshotV3* Layout,
+        std::uint32_t CoreVoxelSizeMicrons)
+    {
+        FPassageClampComparison result;
+        if(Base.debugDensitySamples.empty()
+            ||Base.debugDensitySamples.size()!=Candidate.debugDensitySamples.size())return result;
+        const double root=std::cbrt(static_cast<double>(Base.debugDensitySamples.size()));
+        const std::int32_t dim=static_cast<std::int32_t>(std::llround(root));
+        if(dim<4||static_cast<std::size_t>(dim)*dim*dim!=Base.debugDensitySamples.size())return result;
+        const std::int32_t gridDim=dim-3;
+        const std::int32_t extent=VoxelForgeCore::CoreTileVoxelCount<<Base.key.lod;
+        if(gridDim<=0||extent%gridDim!=0)return result;
+        const std::int32_t step=extent/gridDim;
+        const double voxelSizeCm=static_cast<double>(CoreVoxelSizeMicrons)/10000.0;
+        const std::array<std::int32_t,3> origin={Base.key.coordinate.x*extent,
+            Base.key.coordinate.y*extent,Base.key.coordinate.z*extent};
+        const auto index=[dim](std::int32_t x,std::int32_t y,std::int32_t z)
+        {return (static_cast<std::size_t>(z)*dim+y)*dim+x;};
+        const auto solid=[](float density){return density<0.0f;};
+        for(std::int32_t z=0;z<dim;++z)
+        for(std::int32_t y=0;y<dim;++y)
+        for(std::int32_t x=0;x<dim;++x)
+        {
+            const float a=Base.debugDensitySamples[index(x,y,z)];
+            const float b=Candidate.debugDensitySamples[index(x,y,z)];
+            if(!std::isfinite(a)||!std::isfinite(b))return result;
+            if(a!=b)++result.changedSamples;
+            if(solid(a)!=solid(b))++result.signFlips;
+            result.maxAbsDensityDelta=std::max(result.maxAbsDensityDelta,
+                std::abs(static_cast<double>(a)-b));
+            ++result.samples;
+        }
+        const auto inspectEdge=[&](std::int32_t x,std::int32_t y,std::int32_t z,
+            std::int32_t nx,std::int32_t ny,std::int32_t nz)
+        {
+            const float a0=Base.debugDensitySamples[index(x,y,z)];
+            const float a1=Base.debugDensitySamples[index(nx,ny,nz)];
+            const float b0=Candidate.debugDensitySamples[index(x,y,z)];
+            const float b1=Candidate.debugDensitySamples[index(nx,ny,nz)];
+            const bool crossBase=solid(a0)!=solid(a1);
+            const bool crossCandidate=solid(b0)!=solid(b1);
+            if(crossBase!=crossCandidate)++result.crossingEdgeMismatches;
+            if(!crossBase||!crossCandidate)return;
+            const double ta=static_cast<double>(a0)/(static_cast<double>(a0)-a1);
+            const double tb=static_cast<double>(b0)/(static_cast<double>(b0)-b1);
+            const double displacementCm=std::abs(ta-tb)*step*voxelSizeCm;
+            result.maxSurfaceDisplacementCm=std::max(result.maxSurfaceDisplacementCm,
+                displacementCm);
+            result.sumSurfaceDisplacementCm+=displacementCm;
+            ++result.sharedCrossingEdges;
+            if(displacementCm<=1.0e-9)return;
+            ++result.movedCrossingEdges;
+            std::array<double,3> location={origin[0]+(x-1)*step,
+                origin[1]+(y-1)*step,origin[2]+(z-1)*step};
+            location[0]+=(nx-x)*step*(ta+tb)*0.5;
+            location[1]+=(ny-y)*step*(ta+tb)*0.5;
+            location[2]+=(nz-z)*step*(ta+tb)*0.5;
+            const int region=ClassifyPassageRegion(Layout,location).category;
+            ++result.movedEdgeRegions[static_cast<std::size_t>(region)];
+        };
+        for(std::int32_t z=0;z<dim;++z)
+        for(std::int32_t y=0;y<dim;++y)
+        for(std::int32_t x=0;x<dim;++x)
+        {
+            if(x+1<dim)inspectEdge(x,y,z,x+1,y,z);
+            if(y+1<dim)inspectEdge(x,y,z,x,y+1,z);
+            if(z+1<dim)inspectEdge(x,y,z,x,y,z+1);
+        }
+
+        if(Base.vertices.size()!=Candidate.vertices.size()
+            ||Base.indices!=Candidate.indices)
+            result.normalPairingFailures=1;
+        else
+        {
+            constexpr double RadiansToDegrees=180.0/3.14159265358979323846;
+            for(std::size_t vertex=0;vertex<Base.vertices.size();++vertex)
+            {
+                const auto& a=Base.vertices[vertex].normal;
+                const auto& b=Candidate.vertices[vertex].normal;
+                const double lengthA=std::sqrt(a.x*a.x+a.y*a.y+a.z*a.z);
+                const double lengthB=std::sqrt(b.x*b.x+b.y*b.y+b.z*b.z);
+                if(!(lengthA>0.0&&lengthB>0.0))continue;
+                const double cosine=std::clamp((a.x*b.x+a.y*b.y+a.z*b.z)
+                    /(lengthA*lengthB),-1.0,1.0);
+                const double angle=std::acos(cosine)*RadiansToDegrees;
+                result.maxNormalAngleDegrees=std::max(result.maxNormalAngleDegrees,angle);
+                result.sumNormalAngleDegrees+=angle;
+                ++result.normalVertices;
+                if(angle>1.0e-6)
+                {
+                    ++result.changedNormalVertices;
+                    const double geometryVoxelSizeCm=voxelSizeCm;
+                    const auto& position=Candidate.vertices[vertex].position;
+                    const std::array<double,3> location={position.x/geometryVoxelSizeCm,
+                        position.y/geometryVoxelSizeCm,position.z/geometryVoxelSizeCm};
+                    const int region=ClassifyPassageRegion(Layout,location).category;
+                    ++result.normalVertexRegions[static_cast<std::size_t>(region)];
+                }
+            }
+        }
+        result.meshChanged=Base.meshHash!=Candidate.meshHash
+            ||Base.vertices.size()!=Candidate.vertices.size()
+            ||Base.indices!=Candidate.indices;
+        result.valid=true;
+        return result;
+    }
+
+    struct FPassageSourceGradientStats
+    {
+        std::uint64_t candidateCrossings=0,sourceNearZeroSamples=0;
+        std::vector<double> gradientMagnitudes;
+    };
+
+    inline void GatherPassageSourceGradients(const VoxelForgeCore::World& World,
+        const VoxelForgeCore::TileMesh& Mesh,
+        const VoxelForgeCore::ResolvedLayoutSnapshotV3* Layout,
+        FPassageSourceGradientStats& Stats)
+    {
+        if(Mesh.debugDensitySamples.empty())return;
+        const double root=std::cbrt(static_cast<double>(Mesh.debugDensitySamples.size()));
+        const std::int32_t dim=static_cast<std::int32_t>(std::llround(root));
+        if(dim<4||static_cast<std::size_t>(dim)*dim*dim!=Mesh.debugDensitySamples.size())return;
+        const std::int32_t gridDim=dim-3;
+        const std::int32_t extent=VoxelForgeCore::CoreTileVoxelCount<<Mesh.key.lod;
+        if(gridDim<=0||extent%gridDim!=0)return;
+        const std::int32_t step=extent/gridDim;
+        const std::array<std::int32_t,3> origin={Mesh.key.coordinate.x*extent,
+            Mesh.key.coordinate.y*extent,Mesh.key.coordinate.z*extent};
+        const auto index=[dim](std::int32_t x,std::int32_t y,std::int32_t z)
+        {return (static_cast<std::size_t>(z)*dim+y)*dim+x;};
+        std::uint64_t eligibleCrossings=0;
+        constexpr std::uint64_t SampleStride=32;
+        constexpr double H=1.0;
+        const auto inspect=[&](std::int32_t x,std::int32_t y,std::int32_t z,
+            std::int32_t nx,std::int32_t ny,std::int32_t nz)
+        {
+            const float d0=Mesh.debugDensitySamples[index(x,y,z)];
+            const float d1=Mesh.debugDensitySamples[index(nx,ny,nz)];
+            if((d0<0.0f)==(d1<0.0f))return;
+            const double t=static_cast<double>(d0)/(static_cast<double>(d0)-d1);
+            std::array<double,3> location={origin[0]+(x-1)*step,
+                origin[1]+(y-1)*step,origin[2]+(z-1)*step};
+            location[0]+=(nx-x)*step*t;
+            location[1]+=(ny-y)*step*t;
+            location[2]+=(nz-z)*step*t;
+            if(ClassifyPassageRegion(Layout,location).category!=3)return;
+            ++Stats.candidateCrossings;
+            if((eligibleCrossings++%SampleStride)!=0)return;
+            const VoxelForgeCore::Vec3d point{location[0],location[1],location[2]};
+            const double center=World.passageSourceDensityAt(point);
+            if(!std::isfinite(center)||std::abs(center)>2.0)return;
+            ++Stats.sourceNearZeroSamples;
+            std::array<double,3> gradient{};
+            for(std::size_t axis=0;axis<3;++axis)
+            {
+                auto before=point,after=point;
+                if(axis==0){before.x-=H;after.x+=H;}
+                else if(axis==1){before.y-=H;after.y+=H;}
+                else {before.z-=H;after.z+=H;}
+                gradient[axis]=(World.passageSourceDensityAt(after)
+                    -World.passageSourceDensityAt(before))/(2.0*H);
+            }
+            const double magnitude=std::sqrt(gradient[0]*gradient[0]
+                +gradient[1]*gradient[1]+gradient[2]*gradient[2]);
+            if(std::isfinite(magnitude))Stats.gradientMagnitudes.push_back(magnitude);
+        };
+        for(std::int32_t z=0;z<dim;++z)
+        for(std::int32_t y=0;y<dim;++y)
+        for(std::int32_t x=0;x<dim;++x)
+        {
+            if(x+1<dim)inspect(x,y,z,x+1,y,z);
+            if(y+1<dim)inspect(x,y,z,x,y+1,z);
+            if(z+1<dim)inspect(x,y,z,x,y,z+1);
+        }
+    }
+
+    inline int AuditPassageSourceClamp(VoxelForgeCore::World& Shape,
+        const FStandaloneDesiredTileSet& Desired,
+        const VoxelForgeCore::ResolvedLayoutSnapshotV3* Layout,
+        std::uint32_t CoreVoxelSizeMicrons)
+    {
+        constexpr std::array<double,4> Floors={2.0,3.0,4.0,6.0};
+        std::vector<VoxelForgeCore::TileKey> keys;
+        std::array<std::uint64_t,3> expectedByLod{};
+        for(const FVoxelTileKey& tile:Desired.Tiles)
+        {
+            if(tile.Level<0||tile.Level>2)continue;
+            keys.push_back({{tile.Coord.X,tile.Coord.Y,tile.Coord.Z},tile.Level});
+            ++expectedByLod[static_cast<std::size_t>(tile.Level)];
+        }
+        if(keys.empty())
+        {
+            std::printf("[L91PassageClampAudit] status=FAIL reason=no_lod0_2_tiles\n");
+            return 14;
+        }
+        std::printf("[L91PassageClampCoverage] tiles=%zu lod0=%llu lod1=%llu lod2=%llu mode=full_desired_near_set\n",
+            keys.size(),static_cast<unsigned long long>(expectedByLod[0]),
+            static_cast<unsigned long long>(expectedByLod[1]),
+            static_cast<unsigned long long>(expectedByLod[2]));
+        VoxelForgeCore::TileGenerationOptions baseOptions;
+        baseOptions.hashDensity=true;
+        baseOptions.captureDensitySamples=true;
+        baseOptions.forceFullDensityCapture=true;
+        baseOptions.skipUvAndColors=true;
+        baseOptions.skipMaterialGroups=true;
+        VoxelForgeCore::TileGenerationOptions candidateOptions=baseOptions;
+        candidateOptions.profilePassageComposer=true;
+        std::array<std::uint64_t,4> tileCount{},sampleCount{},changedSamples{},signFlips{},
+            crossingMismatches{},sharedCrossings{},movedCrossings{},changedTiles{},
+            normalVertices{},normalPairingFailures{},changedNormalVertices{};
+        std::array<std::uint64_t,4> movedRegions[4]{},normalRegions[4]{};
+        std::array<double,4> maxDisplacementCm{},sumDisplacementCm{},maxNormalAngle{};
+        std::array<double,4> sumNormalAngle{};
+        FPassageSourceGradientStats gradientStats;
+        std::uint64_t generationFailures=0,invalidComparisons=0;
+        for(const VoxelForgeCore::TileKey& key:keys)
+        {
+            std::string error;
+            const auto base=Shape.generateTile(key,baseOptions,error);
+            if(!base)
+            {
+                ++generationFailures;
+                std::printf("[L91PassageClampTileFailure] mode=base key=(%d,%d,%d,lod%d) error=%s\n",
+                    key.coordinate.x,key.coordinate.y,key.coordinate.z,key.lod,error.c_str());
+                continue;
+            }
+            GatherPassageSourceGradients(Shape,*base,Layout,gradientStats);
+            for(std::size_t floorIndex=0;floorIndex<Floors.size();++floorIndex)
+            {
+                candidateOptions.diagnosticPassageSourceFloorVoxels=Floors[floorIndex];
+                error.clear();
+                const auto candidate=Shape.generateTile(key,candidateOptions,error);
+                if(!candidate)
+                {
+                    ++generationFailures;
+                    std::printf("[L91PassageClampTileFailure] floor_vox=%.0f key=(%d,%d,%d,lod%d) error=%s\n",
+                        Floors[floorIndex],key.coordinate.x,key.coordinate.y,key.coordinate.z,
+                        key.lod,error.c_str());
+                    continue;
+                }
+                const FPassageClampComparison comparison=ComparePassageClampMeshes(
+                    *base,*candidate,Layout,CoreVoxelSizeMicrons);
+                if(!comparison.valid)
+                {
+                    ++invalidComparisons;
+                    continue;
+                }
+                ++tileCount[floorIndex];
+                sampleCount[floorIndex]+=comparison.samples;
+                changedSamples[floorIndex]+=comparison.changedSamples;
+                signFlips[floorIndex]+=comparison.signFlips;
+                crossingMismatches[floorIndex]+=comparison.crossingEdgeMismatches;
+                sharedCrossings[floorIndex]+=comparison.sharedCrossingEdges;
+                movedCrossings[floorIndex]+=comparison.movedCrossingEdges;
+                changedTiles[floorIndex]+=comparison.meshChanged?1u:0u;
+                normalVertices[floorIndex]+=comparison.normalVertices;
+                normalPairingFailures[floorIndex]+=comparison.normalPairingFailures;
+                changedNormalVertices[floorIndex]+=comparison.changedNormalVertices;
+                maxDisplacementCm[floorIndex]=std::max(maxDisplacementCm[floorIndex],
+                    comparison.maxSurfaceDisplacementCm);
+                sumDisplacementCm[floorIndex]+=comparison.sumSurfaceDisplacementCm;
+                maxNormalAngle[floorIndex]=std::max(maxNormalAngle[floorIndex],
+                    comparison.maxNormalAngleDegrees);
+                sumNormalAngle[floorIndex]+=comparison.sumNormalAngleDegrees;
+                for(std::size_t region=0;region<4;++region)
+                {
+                    movedRegions[floorIndex][region]+=comparison.movedEdgeRegions[region];
+                    normalRegions[floorIndex][region]+=comparison.normalVertexRegions[region];
+                }
+                std::printf("[L91PassageClampTile] floor_vox=%.0f key=(%d,%d,%d,lod%d) samples=%llu changed=%llu sign_flips=%llu moved_edges=%llu max_displacement_cm=%.6g normal_vertices=%llu max_normal_degrees=%.6g changed_mesh=%d\n",
+                    Floors[floorIndex],key.coordinate.x,key.coordinate.y,key.coordinate.z,key.lod,
+                    static_cast<unsigned long long>(comparison.samples),
+                    static_cast<unsigned long long>(comparison.changedSamples),
+                    static_cast<unsigned long long>(comparison.signFlips),
+                    static_cast<unsigned long long>(comparison.movedCrossingEdges),
+                    comparison.maxSurfaceDisplacementCm,
+                    static_cast<unsigned long long>(comparison.normalVertices),
+                    comparison.maxNormalAngleDegrees,comparison.meshChanged?1:0);
+            }
+        }
+        bool acceptedAtAllFloors=generationFailures==0&&invalidComparisons==0
+            &&keys.size()>0;
+        for(std::size_t floorIndex=0;floorIndex<Floors.size();++floorIndex)
+        {
+            const double meanDisplacement=sharedCrossings[floorIndex]
+                ?sumDisplacementCm[floorIndex]/sharedCrossings[floorIndex]:0.0;
+            const double meanNormal=normalVertices[floorIndex]
+                ?sumNormalAngle[floorIndex]/normalVertices[floorIndex]:0.0;
+            const bool accepted=tileCount[floorIndex]==keys.size()
+                &&signFlips[floorIndex]==0&&crossingMismatches[floorIndex]==0
+                &&maxDisplacementCm[floorIndex]<=1.0
+                &&maxNormalAngle[floorIndex]<=2.0
+                &&normalPairingFailures[floorIndex]==0;
+            acceptedAtAllFloors=acceptedAtAllFloors&&accepted;
+            std::printf("[L91PassageClampSummary] floor_vox=%.0f tiles=%llu/%zu samples=%llu changed_samples=%llu sign_flips=%llu edge_crossing_mismatches=%llu shared_crossings=%llu moved_crossings=%llu max_displacement_cm=%.6g mean_displacement_cm=%.6g changed_mesh_tiles=%llu normal_vertices=%llu changed_normal_vertices=%llu max_normal_degrees=%.6g mean_normal_degrees=%.6g normal_pairing_failures=%llu moved_regions=(wall:%llu,floor:%llu,mouth:%llu,other:%llu) normal_regions=(wall:%llu,floor:%llu,mouth:%llu,other:%llu) status=%s\n",
+                Floors[floorIndex],static_cast<unsigned long long>(tileCount[floorIndex]),
+                keys.size(),static_cast<unsigned long long>(sampleCount[floorIndex]),
+                static_cast<unsigned long long>(changedSamples[floorIndex]),
+                static_cast<unsigned long long>(signFlips[floorIndex]),
+                static_cast<unsigned long long>(crossingMismatches[floorIndex]),
+                static_cast<unsigned long long>(sharedCrossings[floorIndex]),
+                static_cast<unsigned long long>(movedCrossings[floorIndex]),
+                maxDisplacementCm[floorIndex],meanDisplacement,
+                static_cast<unsigned long long>(changedTiles[floorIndex]),
+                static_cast<unsigned long long>(normalVertices[floorIndex]),
+                static_cast<unsigned long long>(changedNormalVertices[floorIndex]),
+                maxNormalAngle[floorIndex],meanNormal,
+                static_cast<unsigned long long>(normalPairingFailures[floorIndex]),
+                static_cast<unsigned long long>(movedRegions[floorIndex][0]),
+                static_cast<unsigned long long>(movedRegions[floorIndex][1]),
+                static_cast<unsigned long long>(movedRegions[floorIndex][2]),
+                static_cast<unsigned long long>(movedRegions[floorIndex][3]),
+                static_cast<unsigned long long>(normalRegions[floorIndex][0]),
+                static_cast<unsigned long long>(normalRegions[floorIndex][1]),
+                static_cast<unsigned long long>(normalRegions[floorIndex][2]),
+                static_cast<unsigned long long>(normalRegions[floorIndex][3]),
+                accepted?"PASS":"FAIL");
+        }
+        std::sort(gradientStats.gradientMagnitudes.begin(),
+            gradientStats.gradientMagnitudes.end());
+        const auto percentile=[](const std::vector<double>& values,double p)
+        {
+            if(values.empty())return 0.0;
+            const std::size_t index=std::min(values.size()-1,
+                static_cast<std::size_t>(std::ceil(p*values.size())-1));
+            return values[index];
+        };
+        const double gradientMean=gradientStats.gradientMagnitudes.empty()?0.0:
+            std::accumulate(gradientStats.gradientMagnitudes.begin(),
+                gradientStats.gradientMagnitudes.end(),0.0)
+                /gradientStats.gradientMagnitudes.size();
+        std::printf("[L91PassageSourceGradient] surface_source_crossings=%llu sampled_near_zero=%llu gradient_samples=%zu step_vox=1 source_abs_limit_vox=2 p50=%.6g p90=%.6g max=%.6g mean=%.6g status=%s\n",
+            static_cast<unsigned long long>(gradientStats.candidateCrossings),
+            static_cast<unsigned long long>(gradientStats.sourceNearZeroSamples),
+            gradientStats.gradientMagnitudes.size(),percentile(gradientStats.gradientMagnitudes,0.5),
+            percentile(gradientStats.gradientMagnitudes,0.9),
+            gradientStats.gradientMagnitudes.empty()?0.0:gradientStats.gradientMagnitudes.back(),
+            gradientMean,gradientStats.gradientMagnitudes.size()>=64?"MEASURED":"LOW_SAMPLE");
+        std::printf("[L91PassageClampAudit] tiles=%zu generation_failures=%llu invalid_comparisons=%llu status=%s\n",
+            keys.size(),static_cast<unsigned long long>(generationFailures),
+            static_cast<unsigned long long>(invalidComparisons),
+            acceptedAtAllFloors?"PASS":"FAIL");
+        return acceptedAtAllFloors?0:14;
+    }
+
     struct FLandmarkReachabilityResult
     {
         std::uint64_t pathSamples=0,capsuleSamples=0,blockedCapsuleSamples=0;
@@ -1885,7 +2305,7 @@ namespace StandaloneStreamBenchmark
         bool bLinux77Profile=false,int32 SchedulerPolicy=-1,
         bool bMovingCameraTrace=false,double MovingCameraSpeedMetersPerSecond=0.0,
         double MovingCameraDurationSeconds=12.0,double MovingCameraDwellSeconds=5.0,
-        bool bColdWorkerTimeline=false)
+        bool bColdWorkerTimeline=false,bool bAuditPassageSourceClamp=false)
     {
         using Clock=std::chrono::steady_clock;
         const std::clock_t ColdCpuOrigin=std::clock();
@@ -2054,7 +2474,8 @@ namespace StandaloneStreamBenchmark
         const bool bFarWorldAudit=bAuditNativeCaves||bAuditNativeLattice||bAuditMotifIntervals
             ||bAuditOreVeinYield||bAuditLandmarkReachability||bAuditStrateTransitions
             ||bAuditResolvedLayoutPassages||bAuditResolvedLayoutBoundaries
-            ||bAuditTileShapeReadiness||bAuditBasePageEquivalence||bAuditRouteParity;
+            ||bAuditTileShapeReadiness||bAuditBasePageEquivalence||bAuditRouteParity
+            ||bAuditPassageSourceClamp;
         const bool bDeferFarWorld=bIncludeFarWorld&&!bMovingCameraTrace&&!bFarWorldAudit;
         VoxelForgeCore::ShapeBuildRequest ShapeRequest;
         ShapeRequest.minVoxel={FineMin.X,FineMin.Y,FineMin.Z};
@@ -2134,6 +2555,12 @@ namespace StandaloneStreamBenchmark
             Streamer.Stop();
             std::fprintf(stderr,"[StreamPipeline] full shape build failed: %s\n",BuildError.c_str());return 2;
         }
+        if(bAuditPassageSourceClamp)
+        {
+            Streamer.Stop();
+            return AuditPassageSourceClamp(Shape,Desired,ResolvedLayout,
+                World.CoreVoxelSizeMicrons);
+        }
         if(bAuditNativeCaves)
         {
             Streamer.Stop();