core: cave planner holds for 16 seeds; mouth joints planned from the resolved mouth (L135, v236)

Mouth floor/profile carried into the first/last edges (fixes seeds 1 and 2); fixed a Q16/Q32 scale bug in the mouth
clearance scorer; shortest grade-safe handles; bounded cave AABBs and hoisted edge-BVH normalisation. Seeds 0-15 pass
all composed audits and negative controls; fast tier, Clang/GCC W1/W8/W12 green. Near-ready still +3.9..+13.7% vs
assembler/world (Surface World +3.9..+8.2% with no caves). Not for merge.

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

Standalone/Core/src/ShapeWorldInternal.h

@@ -255,6 +255,7 @@ public:
         {
             double signedDistance=std::numeric_limits<double>::infinity();
             double shellSignedDistance=std::numeric_limits<double>::infinity();
+            double floorShellSignedDistance=std::numeric_limits<double>::infinity();
             double roundSignedDistance=std::numeric_limits<double>::infinity();
             double centerZSubvoxels=0.0,floorCenterZSubvoxels=0.0;
             double radiusSubvoxels=0.0,floorDepthSubvoxels=0.0;
@@ -308,6 +309,14 @@ public:
             stampIndices_=shape.BuildStampTileList(minimumSubvoxels_,maximumSubvoxels_);
             cavernFeatureIndices_=shape.BuildCavernFeatureTileList(
                 minimumSubvoxels_,maximumSubvoxels_);
+            if(profileStats_)
+                for(const std::uint32_t index:cavernFeatureIndices_)
+                {
+                    if(index>=shape.CavernRuntime.size())continue;
+                    const auto& feature=shape.CavernRuntime[index];
+                    if(feature.room)++profileStats_->cavernRoomCandidates;
+                    else if(feature.edge)++profileStats_->cavernEdgeCandidates;
+                }
             passageRoutes_.assign(shape.ResolvedLayout
                 ?shape.ResolvedLayout->passages.size():0,0);
             passageRouteSegments_.resize(passageRoutes_.size());
@@ -1206,11 +1215,15 @@ public:
         auto* passageProfile=passageTileScopeMatches
             ?passageTileQueries->profileStats():nullptr;
         if(passageProfile)++passageProfile->passageComposerQueries;
+        if(passageProfile&&nativeTunnelFieldDensity
+            !=std::numeric_limits<float>::lowest())
+            ++passageProfile->nativeCaveFieldSamples;
 
         struct FNearestTubeSample
         {
             double signedDistance=std::numeric_limits<double>::infinity();
             double shellSignedDistance=std::numeric_limits<double>::infinity();
+            double floorShellSignedDistance=std::numeric_limits<double>::infinity();
             double roundSignedDistance=std::numeric_limits<double>::infinity();
             double centerZ=0.0,floorCenterZ=0.0,radius=0.0,floorDepth=0.0;
             double t=0.0,floorT=0.0;
@@ -1220,13 +1233,32 @@ public:
         };
         double unionDistance=std::numeric_limits<double>::infinity();
         double unionShellDistance=std::numeric_limits<double>::infinity();
+        double unionFloorShellDistance=std::numeric_limits<double>::infinity();
+        double plannedTunnelPassageShellDistance=std::numeric_limits<double>::infinity();
         const std::uint32_t reliefSeed=static_cast<std::uint32_t>(Owner?Owner->Seed:0);
         const auto* queryStratum=FindBoundStratumForManagerZ(Z);
+        const bool plannedTunnelStratum=queryStratum&&queryStratum->Resolved
+            &&queryStratum->Resolved->generatorKind=="TunnelNetwork"
+            &&queryStratum->Resolved->recipeId=="Core.Caves.PrimitiveField"
+            &&queryStratum->Resolved->recipeVersion==1;
         for(std::size_t passageIndex=0;passageIndex<ResolvedLayout->passages.size();
             ++passageIndex)
         {
             const auto& passage=ResolvedLayout->passages[passageIndex];
             if(passage.controlPoints.size()<2)continue;
+            const bool surfaceDepartureLanding=queryStratum&&queryStratum->Resolved
+                &&queryStratum->Resolved->lowerInterfaceCapabilities.surfaceToTunnelLandingSupport
+                &&passage.upperStrateIndex==queryStratum->StrateIndex;
+            const auto floorThicknessWithLanding=[&](double floorThickness,
+                double smoothFloorBlend,double alongMetres)
+            {
+                if(!surfaceDepartureLanding)return floorThickness;
+                const double fade=std::clamp(1.0-alongMetres/8.0,0.0,1.0);
+                const double smoothFade=fade*fade*(3.0-2.0*fade);
+                const double landingThickness=0.50*qPerMetre
+                    *smoothFloorBlend*smoothFade;
+                return std::max(floorThickness,landingThickness);
+            };
             const bool passageTargetsNativeCaveField=queryStratum&&queryStratum->Resolved
                 &&queryStratum->Resolved->passageCapabilities.hasNativeCaveField
                 &&passage.lowerStrateIndex==queryStratum->StrateIndex;
@@ -1235,6 +1267,8 @@ public:
                 &&queryStratum->Resolved->generatorKind=="TunnelNetwork"
                 &&queryStratum->Resolved->recipeId=="Core.Caves.PrimitiveField"
                 &&queryStratum->Resolved->recipeVersion==1;
+            const double mouthShellBlendMetres=passageTargetsPlannedTunnelNetwork
+                ?2.0:MouthShellBlendMetres;
             // Legacy native cave fields own the floor and mouth carve on their
             // lower-strate boundary. The planner's TunnelNetwork field instead
             // needs the shared passage composer to carry its incoming mouth open.
@@ -1390,7 +1424,7 @@ public:
                     const double mouthDistanceMetres=std::max(0.0,std::min(alongMetres,
                         constants.totalPathLengthMetres-alongMetres));
                     const double shellFade=std::clamp(mouthDistanceMetres/
-                        MouthShellBlendMetres,0.0,1.0);
+                        mouthShellBlendMetres,0.0,1.0);
                     const double smoothShellFade=shellFade*shellFade
                         *(3.0-2.0*shellFade);
                     const double floorDistanceMetres=(floorCenterZ-floorDepth-qz)
@@ -1408,12 +1442,16 @@ public:
                         const double pastMouthMetres=std::max(0.0,alongMetres
                             -constants.totalPathLengthMetres);
                         const double extensionFade=std::clamp(1.0
-                            -pastMouthMetres/MouthShellBlendMetres,0.0,1.0);
+                            -pastMouthMetres/mouthShellBlendMetres,0.0,1.0);
                         floorExtensionFade=extensionFade*extensionFade
                             *(3.0-2.0*extensionFade);
                     }
-                    const double floorShellThickness=smoothFloorBlend*shellThickness
-                        *floorExtensionFade*smoothShellFade;
+                    const double floorShellThickness=floorThicknessWithLanding(
+                        smoothFloorBlend*(shellThickness
+                            +(passageTargetsPlannedTunnelNetwork?0.25*qPerMetre:0.0))
+                            *floorExtensionFade
+                            *smoothShellFade,
+                        smoothFloorBlend,alongMetres);
                     const double wallShellDistance=PassageRoundedWallShellDistance(
                         flatDistance,wallElevationMetres*qPerMetre,
                         OpenAirSideWallHeightMetres*qPerMetre,mouthWallThickness);
@@ -1421,8 +1459,14 @@ public:
                         static_cast<double>(flatDistance)-floorShellThickness);
                     const double localShellDistance=std::min(wallShellDistance,
                         floorShellDistance);
+                    if(passageTargetsPlannedTunnelNetwork
+                        &&mouthDistanceMetres>=mouthShellBlendMetres)
+                        plannedTunnelPassageShellDistance=std::min(
+                            plannedTunnelPassageShellDistance,localShellDistance);
                     nearest.shellSignedDistance=std::min(nearest.shellSignedDistance,
                         localShellDistance);
+                    nearest.floorShellSignedDistance=std::min(
+                        nearest.floorShellSignedDistance,floorShellDistance);
                 };
                 double shellFloorSearchBoundSq=-1.0;
                 VisitNearestPassageSegmentRange(passageIndex,0,lastIndex-1,
@@ -1439,6 +1483,14 @@ public:
             const double crestFade=std::clamp((OpenAirSideWallHeightMetres
                 -wallElevationMetres)/0.25,0.0,1.0);
             const double smoothCrestFade=crestFade*crestFade*(3.0-2.0*crestFade);
+            const auto& segment=PassageSegmentData[passageIndex][nearest.segmentIndex];
+            const double alongMetres=segment.authoredAlongMetres
+                +nearest.t*segment.authoredLengthMetres;
+            const double mouthDistanceMetres=std::max(0.0,std::min(alongMetres,
+                constants.totalPathLengthMetres-alongMetres));
+            const double shellFade=std::clamp(mouthDistanceMetres/
+                mouthShellBlendMetres,0.0,1.0);
+            const double smoothShellFade=shellFade*shellFade*(3.0-2.0*shellFade);
             const double wallReliefWeight=(0.05+0.95*(1.0-verticalWallAlignment))
                 *smoothCrestFade;
             float relief=0.0f;
@@ -1457,15 +1509,7 @@ public:
             const double shapedDistance=PassageFlatBottomDistance(
                 static_cast<float>(roughRoundDistance),nearest.floorCenterZ,qz,
                 nearest.floorDepth,qPerMetre);
-            const auto& segment=PassageSegmentData[passageIndex][nearest.segmentIndex];
             const auto& floorSegment=PassageSegmentData[passageIndex][nearest.floorSegmentIndex];
-            const double alongMetres=segment.authoredAlongMetres
-                +nearest.t*segment.authoredLengthMetres;
-            const double mouthDistanceMetres=std::max(0.0,std::min(alongMetres,
-                constants.totalPathLengthMetres-alongMetres));
-            const double shellFade=std::clamp(mouthDistanceMetres/
-                MouthShellBlendMetres,0.0,1.0);
-            const double smoothShellFade=shellFade*shellFade*(3.0-2.0*shellFade);
             // Ease both wall and floor shell into the host ground over five metres.
             // The floor shell remains below the floor plane throughout that blend.
             const double floorDistanceMetres=(nearest.floorCenterZ
@@ -1483,18 +1527,26 @@ public:
                 const double pastMouthMetres=std::max(0.0,floorAlongMetres
                     -constants.totalPathLengthMetres);
                 const double extensionFade=std::clamp(1.0
-                    -pastMouthMetres/MouthShellBlendMetres,0.0,1.0);
+                    -pastMouthMetres/mouthShellBlendMetres,0.0,1.0);
                 floorExtensionFade=extensionFade*extensionFade
                     *(3.0-2.0*extensionFade);
             }
-            const double floorShellThickness=smoothFloorBlend*shellThickness
-                *floorExtensionFade*smoothShellFade;
+            const double floorShellThickness=floorThicknessWithLanding(
+                smoothFloorBlend*(shellThickness
+                    +(passageTargetsPlannedTunnelNetwork?0.25*qPerMetre:0.0))
+                    *floorExtensionFade
+                    *smoothShellFade,
+                smoothFloorBlend,alongMetres);
             const double wallShellDistance=PassageRoundedWallShellDistance(
                 shapedDistance,wallElevationMetres*qPerMetre,
                 OpenAirSideWallHeightMetres*qPerMetre,mouthWallThickness);
             const double floorShellDistance=std::max(-static_cast<double>(shapedDistance),
                 static_cast<double>(shapedDistance)-floorShellThickness);
+            nearest.floorShellSignedDistance=std::min(
+                nearest.floorShellSignedDistance,floorShellDistance);
             unionDistance=std::min(unionDistance,static_cast<double>(shapedDistance));
+            unionFloorShellDistance=std::min(unionFloorShellDistance,
+                nearest.floorShellSignedDistance);
             const double localShellDistance=std::min(wallShellDistance,
                 floorShellDistance);
             unionShellDistance=std::min(unionShellDistance,
@@ -1503,12 +1555,131 @@ public:
 
         if(!std::isfinite(unionDistance))return density;
         const float passageAirDistance=static_cast<float>(-unionDistance/Q);
+        const auto plannedPortalWalkCorridorContains=[&]()
+        {
+            if(!queryStratum||!queryStratum->Resolved
+                ||queryStratum->Resolved->generatorKind!="TunnelNetwork"
+                ||queryStratum->Resolved->recipeId!="Core.Caves.PrimitiveField"
+                ||queryStratum->Resolved->recipeVersion!=1)return false;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* first=nullptr;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* second=nullptr;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* third=nullptr;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* lastThree=nullptr;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* lastTwo=nullptr;
+            const VoxelForgeCore::ResolvedLayoutAnchorV2* last=nullptr;
+            std::size_t routeCount=0;
+            for(const auto& anchor:queryStratum->Resolved->anchors)
+            {
+                if(anchor.kind!="route_point"||anchor.values.size()<3)continue;
+                if(routeCount==0)first=&anchor;
+                else if(routeCount==1)second=&anchor;
+                else if(routeCount==2)third=&anchor;
+                lastThree=lastTwo;lastTwo=last;last=&anchor;
+                ++routeCount;
+            }
+            if(routeCount<6||!first||!second||!third||!lastThree||!lastTwo||!last
+                ||!first->stableId.ends_with("000-arrival")
+                ||!second->stableId.ends_with("000-edge-start")
+                ||!lastTwo->stableId.ends_with("998-departure-inner")
+                ||!last->stableId.ends_with("999-departure"))return false;
+            const double metresPerSubvoxel=1.0/qPerMetre;
+            const auto position=[&](const VoxelForgeCore::ResolvedLayoutAnchorV2& anchor)
+            {
+                return std::array<double,3>{anchor.values[0]*metresPerSubvoxel,
+                    anchor.values[1]*metresPerSubvoxel,
+                    anchor.values[2]*metresPerSubvoxel};
+            };
+            const double queryX=X*Q/qPerMetre;
+            const double queryY=Y*Q/qPerMetre;
+            const double queryZ=Z*Q/qPerMetre;
+            const auto nearRouteSegment=[&](const VoxelForgeCore::ResolvedLayoutAnchorV2& start,
+                const VoxelForgeCore::ResolvedLayoutAnchorV2& end,double limit,bool fromDeparture,
+                double distanceToDepartureAfterEnd)
+            {
+                const auto a=position(start),b=position(end);
+                const double dx=b[0]-a[0],dy=b[1]-a[1];
+                const double horizontalLength=std::hypot(dx,dy);
+                if(horizontalLength<=1.0e-9)return false;
+                const double t=std::clamp(((queryX-a[0])*dx
+                    +(queryY-a[1])*dy)/(horizontalLength*horizontalLength),0.0,1.0);
+                const double along=fromDeparture
+                    ?distanceToDepartureAfterEnd+(1.0-t)*horizontalLength
+                    :distanceToDepartureAfterEnd+t*horizontalLength;
+                if(along>limit)return false;
+                const double routeX=a[0]+t*dx,routeY=a[1]+t*dy;
+                if(std::hypot(queryX-routeX,queryY-routeY)>0.80)return false;
+                const double routeFloor=std::lerp(a[2],b[2],t)-1.13;
+                return queryZ>=routeFloor-0.30&&queryZ<=routeFloor+2.25;
+            };
+            constexpr double PortalWalkLeadMetres=8.0;
+            const auto arrival=position(*first),arrivalInner=position(*second);
+            const double arrivalInnerDistance=std::hypot(
+                arrivalInner[0]-arrival[0],arrivalInner[1]-arrival[1]);
+            if(nearRouteSegment(*first,*second,PortalWalkLeadMetres,false,0.0)
+                ||nearRouteSegment(*second,*third,PortalWalkLeadMetres,false,
+                    arrivalInnerDistance))return true;
+            const auto departureInner=position(*lastTwo),departure=position(*last);
+            const double departureTailDistance=std::hypot(
+                departure[0]-departureInner[0],departure[1]-departureInner[1]);
+            return nearRouteSegment(*lastThree,*lastTwo,PortalWalkLeadMetres,true,
+                    departureTailDistance)
+                ||nearRouteSegment(*lastTwo,*last,PortalWalkLeadMetres,true,0.0);
+        };
+        if(plannedTunnelStratum
+            &&nativeTunnelFieldDensity!=std::numeric_limits<float>::lowest()
+            &&nativeTunnelFieldDensity<0.0f)
+        {
+            const double metresPerVoxel=Q/qPerMetre;
+            const double queryZMetres=Z*metresPerVoxel;
+            const double contentBottomMetres=static_cast<double>(
+                queryStratum->Resolved->content.bottomMicrometres)/1000000.0;
+            const double contentTopMetres=static_cast<double>(
+                queryStratum->Resolved->content.topMicrometres)/1000000.0;
+            const double boundaryDistance=std::min(
+                std::abs(queryZMetres-contentBottomMetres),
+                std::abs(queryZMetres-contentTopMetres));
+            const double boundaryJoinBand=std::max(2.0,
+                static_cast<double>(queryStratum->Resolved->transitionWidthMicrometres)
+                    /2000000.0);
+            if(boundaryDistance<=boundaryJoinBand
+                &&std::abs(static_cast<double>(passageAirDistance)*metresPerVoxel)
+                    <=FloorShellThicknessMetres)
+                // A neighboring stratum can be open at a boundary sample even
+                // though the native graph owns solid host rock there. Keep the
+                // authored passage signed distance through that transition band;
+                // otherwise the neighboring field can widen its wall by a whole
+                // shell thickness. Native graph air still wins above via the
+                // positive nativeTunnelFieldDensity path.
+                return passageAirDistance;
+        }
         // Air is the union of the native graph and passage voids. Keeping the
         // signed passage distance outside the void as well gives marching cubes
         // a real negative distance through the floor instead of the terrain's
         // saturated deep-rock value.
+        if(nativeTunnelFieldDensity!=std::numeric_limits<float>::lowest()
+            &&plannedTunnelPassageShellDistance<0.0&&unionDistance>0.0)
+        {
+            if(nativeTunnelFieldDensity>=0.0f&&plannedPortalWalkCorridorContains())
+                return std::max(nativeTunnelFieldDensity,passageAirDistance);
+            return std::min(density,
+                static_cast<float>(plannedTunnelPassageShellDistance/Q));
+        }
         if(nativeTunnelFieldDensity>=0.0f)
+        {
+            // The planner's passage shell remains authoritative through native
+            // cave voids after the explicit mouth fade has ended. Keep this scoped
+            // to the planner-crossing passage shell so nearby portal joints stay open.
+            if(plannedTunnelPassageShellDistance<0.0&&unionDistance>0.0)
+                return std::min(nativeTunnelFieldDensity,
+                    static_cast<float>(plannedTunnelPassageShellDistance/Q));
+            constexpr float NativeCaveAirMarginVoxels=0.75f;
+            if(unionDistance>0.0
+                &&nativeTunnelFieldDensity<NativeCaveAirMarginVoxels
+                &&unionFloorShellDistance<0.0)
+                return std::min(nativeTunnelFieldDensity,
+                    static_cast<float>(unionFloorShellDistance/Q));
             return std::max(nativeTunnelFieldDensity,passageAirDistance);
+        }
         if(nativeFloorSupport!=std::numeric_limits<float>::lowest()
             &&nativeFloorSupport<0.0f)
             return std::min(nativeFloorSupport,unionDistance<=0.0
@@ -2274,6 +2445,10 @@ public:
         SurfaceDistanceQ=std::make_unique_for_overwrite<int16[]>(static_cast<size_t>(NodeCount));
         Substage=Clock::now();
         BuildPackedRockIntervals(Stats.RockIntervalLines);
+        const auto criticalAirInitialStart=Clock::now();
+        const uint64 criticalAirVoxelsBeforeDetail=ApplyCriticalAirPackedSigns();
+        const double criticalAirInitialSeconds=
+            std::chrono::duration<double>(Clock::now()-criticalAirInitialStart).count();
         Stats.PackedSignBuildSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
         // Native density queries for non-heightfield strates use the exact interval
         // evaluator. Build those native intervals before preparing the tunnel sweeps.
@@ -2296,8 +2471,16 @@ public:
         ApplyDetailBand(Stats.DetailBandLines);
         Stats.DetailApplySeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
         Substage=Clock::now();
+        const uint64 criticalAirVoxelsAfterDetail=ApplyCriticalAirPackedSigns();
+        const double criticalAirRepairSeconds=
+            std::chrono::duration<double>(Clock::now()-Substage).count();
+        Substage=Clock::now();
         Stats.SurfaceProxyNodes+=CompleteSignEdgeDistances();
         Stats.SignEdgeDistanceSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
+        Substage=Clock::now();
+        const uint64 criticalAirVoxelsAfterSignRepair=ApplyCriticalAirPackedSigns();
+        const double criticalAirSignEdgeRepairSeconds=
+            std::chrono::duration<double>(Clock::now()-Substage).count();
         Stats.SurfaceSeconds=std::chrono::duration<double>(Clock::now()-Stage).count();
         // Route validation is world-wide. Detail regions reuse the same authored route data and
         // do not need to repeat the 5,642-point world audit for every entering tile group.
@@ -2329,8 +2512,13 @@ public:
             Stats.CandidateMergeLines.WallSeconds*1000.0,Stats.CandidateMergeLines.WorkerSeconds*1000.0,
             Stats.CandidateMergeSeconds*1000.0,Stats.DetailBandLines.WallSeconds*1000.0,
             Stats.DetailBandLines.WorkerSeconds*1000.0);
-        std::printf("[ShapeSubstage] detail_apply=%.3fms sign_edge_distances=%.3fms passage_validation=%.3fms shared_field_primitives=%.3fms far_parents=%.3fms\n",
-            Stats.DetailApplySeconds*1000.0,Stats.SignEdgeDistanceSeconds*1000.0,
+        std::printf("[ShapeSubstage] detail_apply=%.3fms critical_air_sign_repair=%.3fms critical_air_voxels=%llu/%llu/%llu sign_edge_distances=%.3fms passage_validation=%.3fms shared_field_primitives=%.3fms far_parents=%.3fms\n",
+            Stats.DetailApplySeconds*1000.0,criticalAirInitialSeconds*1000.0
+                +criticalAirRepairSeconds*1000.0+criticalAirSignEdgeRepairSeconds*1000.0,
+            static_cast<unsigned long long>(criticalAirVoxelsBeforeDetail),
+            static_cast<unsigned long long>(criticalAirVoxelsAfterDetail),
+            static_cast<unsigned long long>(criticalAirVoxelsAfterSignRepair),
+            Stats.SignEdgeDistanceSeconds*1000.0,
             Stats.PassageValidationSeconds*1000.0,Stats.SharedFieldSeconds*1000.0,
             Stats.FarShapeSeconds*1000.0);
         std::printf("[ShapeBreakdown] owner_shapes=%.3fms owner_shape_worker=%.3fms owner_bins=%.3fms packed_signs=%.3fms passage_prep=%.3fms candidate_sweeps=%.3fms visual_detail_prep=%.3fms detail_band=%.3fms sign_edge_repair=%.3fms route_validation=%.3fms far_parent_shapes=%.3fms far_shared_primitives=%.3fms far_bins=%.3fms\n",
@@ -3402,6 +3590,7 @@ private:
     {
         double floorDepthMetres=0.0,totalPathLengthMetres=0.0;
         double authoredTotalPathLengthMetres=0.0;
+        double upperMouthPlayerCenterHeightMetres=1.13;
         std::size_t routeProfileSegmentCount=0;
         double upperMouthX=0.0,upperMouthY=0.0;
         double upperMouthPlannedFloor=0.0;
@@ -3475,7 +3664,8 @@ private:
             plannedFloor,constants.upperMouthX,constants.upperMouthY,
             constants.upperMouthPlannedFloor,
             constants.upperMouthTangentX,constants.upperMouthTangentY,
-            VoxelForgeCore::PassageSpline::UpperMouthFloorBlendRadiusMetres,1.13,
+            VoxelForgeCore::PassageSpline::UpperMouthFloorBlendRadiusMetres,
+            constants.upperMouthPlayerCenterHeightMetres,
             qPerMetre);
         const double lowerBlendFloor=VoxelForgeCore::PassageSpline::BlendUpperMouthFloorAtXY(
             constants.lowerMouthReceivingRoute,queryXSubvoxels,queryYSubvoxels,
@@ -3594,7 +3784,7 @@ private:
         };
         struct FSegmentNode
         {
-            std::array<double,3> minimum{},maximum{};
+            std::array<double,3> minimum{},maximum{},minimumNormalized{},maximumNormalized{};
             std::size_t first=0,end=0;
             int left=-1,right=-1;
         };
@@ -4174,6 +4364,16 @@ private:
                     return nodeIndex;
                 };
                 buildSegmentNode(buildSegmentNode,0,runtime.segmentOrder.size());
+                const double radius=edge.boreRadiusMicrometres/1000000.0;
+                const double height=edge.boreHeightMicrometres/1000000.0;
+                if(radius>0.0&&height>0.0)
+                    for(auto& node:runtime.segmentNodes)
+                        for(std::size_t axis=0;axis<3;++axis)
+                        {
+                            const double scale=axis==2?height:radius;
+                            node.minimumNormalized[axis]=node.minimum[axis]/scale;
+                            node.maximumNormalized[axis]=node.maximum[axis]/scale;
+                        }
             }
             CavernRuntime.push_back(runtime);
         }
@@ -4623,6 +4823,12 @@ private:
                 passage.lowerMouthControlIndex,1,passage.controlPoints.size()-1);
             auto& constants=PassageComposerConstants[passageIndex];
             constants.routeEndControlIndex=routeEnd;
+            const auto upperStratum=std::find_if(ResolvedLayout->strates.begin(),
+                ResolvedLayout->strates.end(),[&](const auto& stratum)
+                {return stratum.strateIndex==passage.upperStrateIndex;});
+            if(upperStratum!=ResolvedLayout->strates.end()
+                &&upperStratum->generatorKind=="SurfaceWorld")
+                constants.upperMouthPlayerCenterHeightMetres=0.98;
 
             using FRawPassageSegment=VoxelForgeCore::PassageSpline::FSegment;
             std::vector<VoxelForgeCore::PassageSpline::FPoint> controls;
@@ -4640,11 +4846,9 @@ private:
             }
             const double authoredUpperMouthFloorDepth=std::max(0.0,
                 static_cast<double>(passage.controlPoints.front().positionSubvoxels[2]
-                    -passage.upperMouthSubvoxels[2])/qPerMetre+1.13);
+                    -passage.upperMouthSubvoxels[2])/qPerMetre
+                    +constants.upperMouthPlayerCenterHeightMetres);
             double upperMouthFloorDepth=authoredUpperMouthFloorDepth;
-            const auto upperStratum=std::find_if(ResolvedLayout->strates.begin(),
-                ResolvedLayout->strates.end(),[&](const auto& stratum)
-                {return stratum.strateIndex==passage.upperStrateIndex;});
             if(upperStratum!=ResolvedLayout->strates.end()
                 &&(upperStratum->generatorKind=="FloatingIslands"
                     ||upperStratum->generatorKind=="TunnelNetwork"))
@@ -4664,7 +4868,8 @@ private:
                     &&distanceSquared<=std::pow(controls.front()[3]+2.0*qPerMetre,2.0))
                 {
                     upperMouthFloorDepth=std::max(upperMouthFloorDepth,
-                        std::max(0.0,(controls.front()[2]-routeHeight)/qPerMetre+1.13));
+                        std::max(0.0,(controls.front()[2]-routeHeight)/qPerMetre
+                            +constants.upperMouthPlayerCenterHeightMetres));
                     if(upperStratum->generatorKind=="TunnelNetwork")
                         VoxelForgeCore::PassageSpline::BlendEndpointFloorToRoute(
                             controls,plannedFloorProfile,0,route,qPerMetre);
@@ -4761,6 +4966,26 @@ private:
                 constants.upperMouthTangentY=sampledSegments.front().b[1]
                     -sampledSegments.front().a[1];
             }
+            const std::string lowerMouthAnchor=passage.stableId+"/lower-mouth";
+            const std::string upperMouthAnchor=passage.stableId+"/upper-mouth";
+            for(const auto& edge:ResolvedLayout->cavernEdges)
+            {
+                if(edge.controlPointsMicrometres.size()<2)continue;
+                if(edge.startAnchorStableId==lowerMouthAnchor)
+                {
+                    constants.lowerMouthTangentX=edge.controlPointsMicrometres[1][0]
+                        -edge.controlPointsMicrometres[0][0];
+                    constants.lowerMouthTangentY=edge.controlPointsMicrometres[1][1]
+                        -edge.controlPointsMicrometres[0][1];
+                }
+                if(edge.startAnchorStableId==upperMouthAnchor)
+                {
+                    constants.upperMouthTangentX=edge.controlPointsMicrometres[0][0]
+                        -edge.controlPointsMicrometres[1][0];
+                    constants.upperMouthTangentY=edge.controlPointsMicrometres[0][1]
+                        -edge.controlPointsMicrometres[1][1];
+                }
+            }
             std::vector<FRawPassageSegment> rawSegments=sampledSegments;
             std::vector<std::array<double,2>> routeRadiusSamples;
             routeRadiusSamples.push_back({0.0,controls.front()[3]/qPerMetre});
@@ -7563,6 +7788,8 @@ private:
         double floorSupportDepth=0.0,floorSupportFloor=0.0,floorSupportGrade=0.0;
         const std::string* floorSupportEdgeId=nullptr;
         const std::string* floorSupportProfileId=nullptr;
+        double lowestOpenEdgeFloor=std::numeric_limits<double>::infinity();
+        const std::string* lowestOpenEdgeProfileId=nullptr;
         for(const std::uint32_t index:*candidates)
         {
             if(index>=CavernRuntime.size())continue;
@@ -7570,7 +7797,26 @@ private:
             const std::int32_t strateIndex=feature.room?feature.room->strateIndex
                 :feature.edge?feature.edge->strateIndex:-1;
             if(strateIndex!=bound.StrateIndex)continue;
+            // Tile culling keeps the candidate list small, but a tile can still
+            // contain millions of sample points outside a feature's authored
+            // bounds. Reject those points before evaluating room SDFs or walking
+            // an edge's segment BVH. Keep a 1 mm guard for float voxel-coordinate
+            // rounding; the serialized bounds already include all SDF, union,
+            // irregularity, bore, and floor-support reach.
+            constexpr double FeatureBoundsGuardMetres=0.001;
+            bool insideFeatureBounds=true;
+            for(std::size_t axis=0;axis<3;++axis)
+            {
+                const double minimum=feature.boundsMinimumMicrometres[axis]/1000000.0
+                    -FeatureBoundsGuardMetres;
+                const double maximum=feature.boundsMaximumMicrometres[axis]/1000000.0
+                    +FeatureBoundsGuardMetres;
+                if(point[axis]<minimum||point[axis]>maximum)
+                {insideFeatureBounds=false;break;}
+            }
+            if(!insideFeatureBounds)continue;
             double featureVoid=std::numeric_limits<double>::infinity();
+            double edgeFloor=0.0;
             if(feature.room)
             {
                 double normalizedSquared=0.0,meanRadius=0.0;
@@ -7655,15 +7901,16 @@ private:
                             ?(segment.end[2]-segment.start[2])/horizontal:0.0;
                     }
                 };
+                const std::array<double,3> normalizedPoint={
+                    point[0]/radius,point[1]/radius,point[2]/height};
                 const auto nodeLowerBound=[&](const FCavernRuntimeFeature::FSegmentNode& node)
                 {
                     double gapSquared=0.0;
                     for(std::size_t axis=0;axis<3;++axis)
                     {
-                        const double scale=axis==2?height:radius;
-                        const double q=point[axis]/scale;
-                        const double low=node.minimum[axis]/scale;
-                        const double high=node.maximum[axis]/scale;
+                        const double q=normalizedPoint[axis];
+                        const double low=node.minimumNormalized[axis];
+                        const double high=node.maximumNormalized[axis];
                         const double gap=q<low?low-q:q>high?q-high:0.0;
                         gapSquared+=gap*gap;
                     }
@@ -7696,52 +7943,67 @@ private:
                     evaluateSegment(segment);
                 const double candidateSupportDepth=
                     feature.edge->floorSupportDepthMicrometres/1000000.0;
-                if(candidateSupportDepth>0.0&&nearestRadial<radius-0.12
+                constexpr double MinimumBackingDepthMetres=0.65;
+                constexpr double FloorSupportFootprintRadiusMetres=0.95;
+                // Portal edges join a wider authored passage whose floor spans the
+                // full bore. Carry support across that shared mouth footprint;
+                // ordinary backbone and branch edges retain the narrow support
+                // strip that prevents nearby routes from sealing one another.
+                const bool portalMouthEdge=feature.edge->startAnchorStableId.ends_with(
+                    "-mouth");
+                const double floorSupportRadius=portalMouthEdge?radius:
+                    std::min(radius,FloorSupportFootprintRadiusMetres);
+                const double candidateNormalDepth=(nearestFloor-point[2])
+                    /std::sqrt(1.0+nearestGrade*nearestGrade);
+                if(candidateSupportDepth>=MinimumBackingDepthMetres
+                    &&candidateNormalDepth>=MinimumBackingDepthMetres
+                    &&candidateNormalDepth<=candidateSupportDepth
+                    &&nearestRadial<floorSupportRadius-0.12
                     &&std::abs(point[2]-nearestFloor)<=height)
                 {
-                    const double deltaZ=point[2]-nearestFloor;
-                    const double candidateScore=nearestRadial*nearestRadial+deltaZ*deltaZ;
-                    if(!feature.edge->floorProfileStableId.empty())
+                    const double candidateScore=nearestRadial*nearestRadial;
+                    const bool hasProfile=!feature.edge->floorProfileStableId.empty();
+                    const bool sameProfile=floorSupportProfileId&&hasProfile
+                        &&*floorSupportProfileId==feature.edge->floorProfileStableId;
+                    if(!floorSupportProfileId||sameProfile)
                     {
-                        const bool sameProfile=floorSupportProfileId
-                            &&*floorSupportProfileId==feature.edge->floorProfileStableId;
-                        if(!floorSupportProfileId||sameProfile)
-                        {
-                            // Backbone edges share h(s). At a geometric joint their
-                            // cave volumes overlap, so the backing top is the lower
-                            // of the local floors, never the closer higher segment.
-                            if(!floorSupportProfileId||nearestFloor<floorSupportFloor
-                                ||(nearestFloor==floorSupportFloor
-                                    &&feature.edge->stableId<*floorSupportEdgeId))
-                            {
-                                floorSupportScore=candidateScore;
-                                floorSupportDepth=candidateSupportDepth;
-                                floorSupportFloor=nearestFloor;
-                                floorSupportGrade=nearestGrade;
-                                floorSupportEdgeId=&feature.edge->stableId;
-                            }
-                            floorSupportProfileId=&feature.edge->floorProfileStableId;
-                        }
-                    }
-                    else if(!floorSupportProfileId
-                        &&(candidateScore<floorSupportScore
+                        // For a shared backbone, support follows the closest
+                        // horizontal centerline. Vertical separation must not make
+                        // a nearby branch take support away from this path.
+                        if(!floorSupportEdgeId||candidateScore<floorSupportScore
                             ||(candidateScore==floorSupportScore
-                                &&(!floorSupportEdgeId
-                                    ||feature.edge->stableId<*floorSupportEdgeId))))
-                    {
-                        floorSupportScore=candidateScore;
-                        floorSupportDepth=candidateSupportDepth;
-                        floorSupportFloor=nearestFloor;
-                        floorSupportGrade=nearestGrade;
-                        floorSupportEdgeId=&feature.edge->stableId;
+                                &&(nearestFloor<floorSupportFloor
+                                    ||(nearestFloor==floorSupportFloor
+                                        &&feature.edge->stableId<*floorSupportEdgeId))))
+                        {
+                            floorSupportScore=candidateScore;
+                            floorSupportDepth=candidateSupportDepth;
+                            floorSupportFloor=nearestFloor;
+                            floorSupportGrade=nearestGrade;
+                            floorSupportEdgeId=&feature.edge->stableId;
+                        }
+                        if(hasProfile)
+                            floorSupportProfileId=&feature.edge->floorProfileStableId;
                     }
                 }
+                edgeFloor=nearestFloor;
                 const double floor=(nearestFloor-point[2])
                     /std::sqrt(1.0+nearestGrade*nearestGrade);
                 const double width=feature.edge->smoothWidthMicrometres/1000000.0;
                 featureVoid=SmoothMaxMetres(tube,floor,width);
             }
             if(!std::isfinite(featureVoid))continue;
+            if(feature.edge&&feature.edge->floorSupportDepthMicrometres>=650000
+                &&featureVoid<0.0)
+            {
+                if(edgeFloor<lowestOpenEdgeFloor
+                    ||(edgeFloor==lowestOpenEdgeFloor&&feature.edge->floorProfileStableId
+                        <(lowestOpenEdgeProfileId?*lowestOpenEdgeProfileId:std::string{})))
+                {
+                    lowestOpenEdgeFloor=edgeFloor;
+                    lowestOpenEdgeProfileId=&feature.edge->floorProfileStableId;
+                }
+            }
             if(!std::isfinite(caveVoid))caveVoid=featureVoid;
             else caveVoid=SmoothMinMetres(caveVoid,featureVoid,
                 feature.room
@@ -7752,8 +8014,10 @@ private:
                         ?feature.edge->unionWidthMicrometres
                         :feature.edge->smoothWidthMicrometres)/1000000.0);
         }
+        const double floorSupportNormalDepth=(floorSupportFloor-point[2])
+            /std::sqrt(1.0+floorSupportGrade*floorSupportGrade);
         if(std::isfinite(floorSupportScore)&&point[2]<floorSupportFloor
-            &&floorSupportFloor-point[2]<=floorSupportDepth)
+            &&floorSupportNormalDepth<=floorSupportDepth)
             nativeFloorSupportMinimum=(point[2]-floorSupportFloor)
                 /std::sqrt(1.0+floorSupportGrade*floorSupportGrade);
         // A versioned native caves recipe owns a solid host-rock field.  The
@@ -7767,7 +8031,15 @@ private:
         // Preserve each native graph edge's planned floor backing after smooth
         // unions. The record's finite depth keeps independent routes from sealing
         // one another when they pass at different elevations.
-        if(std::isfinite(nativeFloorSupportMinimum))
+        // Backing from a higher route edge must not seal a lower overlapping bore.
+        // Room voids and same-level route joins still retain their authored support.
+        const bool sameContinuousFloorProfile=floorSupportProfileId
+            &&lowestOpenEdgeProfileId&&!floorSupportProfileId->empty()
+            &&*floorSupportProfileId==*lowestOpenEdgeProfileId;
+        const bool sealsOpenLowerEdge=std::isfinite(lowestOpenEdgeFloor)
+            &&lowestOpenEdgeFloor<floorSupportFloor-0.50
+            &&point[2]>lowestOpenEdgeFloor&&!sameContinuousFloorProfile;
+        if(std::isfinite(nativeFloorSupportMinimum)&&!sealsOpenLowerEdge)
             composed=std::min(composed,nativeFloorSupportMinimum);
         if(nativeFloorSupport&&std::isfinite(nativeFloorSupportMinimum))
             *nativeFloorSupport=static_cast<float>(nativeFloorSupportMinimum/metresPerVoxel);
@@ -9748,6 +10020,32 @@ private:
         },&Timing,nullptr,16);
     }
 
+    uint64 ApplyCriticalAirPackedSigns()
+    {
+        const int32 NX=Size[0],NY=Size[1];
+        std::array<uint64,16> workerVoxels{};
+        ParallelLines(static_cast<size_t>(NX)*NY,[&](size_t Line,int32 Worker)
+        {
+            const int32 X=Min[0]+static_cast<int32>(Line%NX);
+            const int32 Y=Min[1]+static_cast<int32>(Line/NX);
+            const size_t Base=Line*WordsPerZ;
+            for(const uint32 Id:GetLineCandidates(2,X,Y))
+            {
+                const FPrimitive& primitive=Primitives[Id];
+                if(!primitive.bCarve||!primitive.bCritical)continue;
+                const int32 lo=std::max(primitive.Min[2],Min[2]);
+                const int32 hi=std::min(primitive.Max[2],Max[2]);
+                for(int32 Z=lo;Z<=hi;++Z)
+                {
+                    if(!ShapeContains(primitive,X,Y,Z))continue;
+                    FillBits(RockWords,Base,Z-Min[2],Z-Min[2],false);
+                    ++workerVoxels[static_cast<size_t>(Worker)];
+                }
+            }
+        },nullptr,nullptr,16);
+        return std::accumulate(workerVoxels.begin(),workerVoxels.end(),uint64{0});
+    }
+
     void BuildCandidateBands(FParallelTiming& AxisTiming,FParallelTiming& MergeTiming,
                              double& MergeSeconds)
     {
@@ -11491,7 +11789,8 @@ private:
                     const int32 VZ=static_cast<int32>(std::lround(Z));
                     const bool bCritical=IsInsideCriticalAir(VX,VY,VZ);
                     if(bCritical){++RouteCritical;++SegmentCritical;}
-                    if(IsRock(VX,VY,VZ))
+                    const bool bRock=IsRock(VX,VY,VZ);
+                    if(bRock)
                     {
                         ++Stats.WalkFailures;++RouteFailures;++SegmentFailures;
                         if(RouteFailures==1)
@@ -11705,7 +12004,7 @@ inline void FStandaloneShapeWorld::FScopedPassageTileQueries::prepareSweptTubeBa
             ?shape_->ResolvedLayout->coreVoxelSizeMicrometres:250000);
     const double shellThickness=VF_PassageShellThicknessMetres*qPerMetre;
     const double stampedOutsideDistance=sweep->influenceSubvoxels+1.0;
-    constexpr double MouthShellBlendMetres=5.0;
+    constexpr double DefaultMouthShellBlendMetres=5.0;
     const double wallReliefShell=0.41*qPerMetre;
     const double floorDetailShell=1.0*qPerMetre;
     if(profile)
@@ -11730,6 +12029,19 @@ inline void FStandaloneShapeWorld::FScopedPassageTileQueries::prepareSweptTubeBa
     {
         const auto& candidates=passageRouteSegments_[passageIndex];
         if(candidates.empty())continue;
+        double mouthShellBlendMetres=DefaultMouthShellBlendMetres;
+        if(shape_->ResolvedLayout&&passageIndex<shape_->ResolvedLayout->passages.size())
+        {
+            const auto& passage=shape_->ResolvedLayout->passages[passageIndex];
+            const auto lower=std::find_if(shape_->ResolvedLayout->strates.begin(),
+                shape_->ResolvedLayout->strates.end(),[&](const auto& stratum)
+                    {return stratum.strateIndex==passage.lowerStrateIndex;});
+            if(lower!=shape_->ResolvedLayout->strates.end()
+                &&lower->generatorKind=="TunnelNetwork"
+                &&lower->recipeId=="Core.Caves.PrimitiveField"
+                &&lower->recipeVersion==1)
+                mouthShellBlendMetres=2.0;
+        }
         const std::int32_t sweepIndex=static_cast<std::int32_t>(sweep->passages.size());
         sweep->passageToSweep[passageIndex]=sweepIndex;
         auto& passageSamples=sweep->passages.emplace_back();
@@ -11883,7 +12195,7 @@ inline void FStandaloneShapeWorld::FScopedPassageTileQueries::prepareSweptTubeBa
                     const double mouthDistanceMetres=std::max(0.0,std::min(alongMetres,
                         constants.totalPathLengthMetres-alongMetres));
                     const double shellFade=std::clamp(mouthDistanceMetres/
-                        MouthShellBlendMetres,0.0,1.0);
+                        mouthShellBlendMetres,0.0,1.0);
                     const double smoothShellFade=shellFade*shellFade
                         *(3.0-2.0*shellFade);
                     const double floorDistanceMetres=(floorCenterZ-floorDepth-qz)/qPerMetre;
@@ -11900,7 +12212,7 @@ inline void FStandaloneShapeWorld::FScopedPassageTileQueries::prepareSweptTubeBa
                         const double pastMouthMetres=std::max(0.0,alongMetres
                             -constants.totalPathLengthMetres);
                         const double extensionFade=std::clamp(1.0
-                            -pastMouthMetres/MouthShellBlendMetres,0.0,1.0);
+                            -pastMouthMetres/mouthShellBlendMetres,0.0,1.0);
                         floorExtensionFade=extensionFade*extensionFade
                             *(3.0-2.0*extensionFade);
                     }