wip(L27, side branch): passages cross open voids inside shared natural rock columns

Unsupported passage runs > 12.5 m become a solid relief-bearing column (ceiling/island to
ground, flared base) with the helix inside, for every recipe; FI anchor uses the same path.
All 4 styles x both recipes: 0/0/0, 0 open-air, naturalness pass; no-long-bridge audit (L26
fails it). Deterministic, Clang = GCC. Look approved; cost +35% SW / +19% FI blocks merge (L28).

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

Standalone/Core/src/ShapeWorldInternal.h

@@ -41,27 +41,31 @@ public:
         double SealThickness=0.0;
     };
 
-    const std::vector<FStandalonePassageBridgeRange>& GetPassageBridgeRanges() const
-    {return PassageBridgeRanges;}
+    const std::vector<FStandalonePassageVoidCrossing>& GetPassageVoidCrossings() const
+    {return PassageVoidCrossings;}
 
-    bool IsResolvedPassageBridgeSample(std::size_t PassageIndex,std::size_t SegmentIndex,
+    bool IsResolvedPassageColumnSample(std::size_t PassageIndex,std::size_t SegmentIndex,
         const VoxelForgeCore::Vec3d& Position) const
     {
-        if(IsPassageBridgeSegment(PassageIndex,SegmentIndex)
-            &&PassageBridgeSignedDistance(PassageIndex,SegmentIndex,
-                static_cast<float>(Position.x),static_cast<float>(Position.y),
-                static_cast<float>(Position.z))<=0.0)return true;
-        for(const auto& range:PassageBridgeRanges)
+        (void)SegmentIndex;
+        for(const auto& range:PassageVoidCrossings)
         {
-            if(range.passageIndex!=PassageIndex)continue;
-            for(std::size_t segment=range.firstSegment;segment<=range.lastSegment;++segment)
-                if(segment!=SegmentIndex&&PassageBridgeSignedDistance(PassageIndex,segment,
-                    static_cast<float>(Position.x),static_cast<float>(Position.y),
-                    static_cast<float>(Position.z))<=0.0)return true;
+            if(!range.needsColumn||range.passageIndex!=PassageIndex)continue;
+            if(PassageColumnSignedDistance(range,static_cast<float>(Position.x),
+                static_cast<float>(Position.y),static_cast<float>(Position.z))<=0.0)return true;
         }
         return false;
     }
 
+    bool IsResolvedPassageShortSpanSample(std::size_t PassageIndex,std::size_t SegmentIndex,
+        const VoxelForgeCore::Vec3d& Position) const
+    {
+        return IsPassageShortSpanSegment(PassageIndex,SegmentIndex)
+            &&PassageBridgeSignedDistance(PassageIndex,SegmentIndex,
+                static_cast<float>(Position.x),static_cast<float>(Position.y),
+                static_cast<float>(Position.z))<=0.0;
+    }
+
     double GetCoreVoxelSizeCm() const
     {
         return Owner == nullptr || Owner->CoreVoxelSizeMicrons == 0
@@ -197,6 +201,13 @@ public:
                 -passage.controlPoints.front().radiusSubvoxels+playerCenterAboveFloorQ;
             const double lastFloorQ=passage.controlPoints.back().positionSubvoxels[2]
                 -passage.controlPoints.back().radiusSubvoxels+playerCenterAboveFloorQ;
+            for(const auto& crossing:PassageVoidCrossings)
+            {
+                if(!crossing.needsColumn||crossing.passageIndex!=passageIndex
+                    ||qz>crossing.topZSubvoxels||qz<crossing.bottomZSubvoxels)continue;
+                const double columnDistance=PassageColumnSignedDistance(crossing,X,Y,Z);
+                composed=std::min(composed,static_cast<float>(columnDistance/Q));
+            }
             if(qz>firstFloorQ+2.0*passage.mouthRadiusSubvoxels
                 ||qz<lastFloorQ-2.0*passage.mouthRadiusSubvoxels)
             {
@@ -297,7 +308,7 @@ public:
             const double wallReliefWeight=1.0-0.80*verticalWallAlignment;
             const double roughSignedDistance=bestSignedDistance
                 +static_cast<double>(std::clamp(relief,-1.0f,1.0f))*0.24*qPerMetre*wallReliefWeight;
-            if(IsPassageBridgeSegment(passageIndex,static_cast<std::size_t>(bestIndex)))
+            if(IsPassageShortSpanSegment(passageIndex,static_cast<std::size_t>(bestIndex)))
             {
                 const double bridgeDistance=PassageBridgeSignedDistance(passageIndex,
                     static_cast<std::size_t>(bestIndex),X,Y,Z);
@@ -317,8 +328,9 @@ public:
                 const double radiusB=segmentB.radiusSubvoxels;
                 // Keep the tread within the probe band and below the capsule's
                 // lowest sampled point.
-                const double floorOffset=IsPassageBridgeSegment(passageIndex,
+                const double floorOffset=IsPassageShortSpanSegment(passageIndex,
                     static_cast<std::size_t>(index))
+                    ||IsPassageColumnSegment(passageIndex,static_cast<std::size_t>(index))
                     ?PassageBridgeDeckOffsetMetres(passageIndex,static_cast<std::size_t>(index))
                     :0.20;
                 const double horizontalLengthSq=dx*dx+dy*dy;
@@ -387,11 +399,14 @@ public:
                 considerSupportSegment(index);
             // Keep route treads inside the native rock envelope. Carving may reopen the
             // floor above this point, but a support cannot create a new surface in air.
-            const bool bridgeFloorSupport=hasSupportFloor
-                &&IsPassageBridgeSegment(passageIndex,
+            const bool passageColumnFloorSupport=hasSupportFloor
+                &&IsPassageColumnSegment(passageIndex,
+                    static_cast<std::size_t>(bestSupportSegmentIndex));
+            const bool shortSpanFloorSupport=hasSupportFloor
+                &&IsPassageShortSpanSegment(passageIndex,
                     static_cast<std::size_t>(bestSupportSegmentIndex));
             if(hasSupportFloor&&bestPlayerCapsuleSignedDistance>=0.05*qPerMetre
-                &&(density<0.0f||bridgeFloorSupport))
+                &&(density<0.0f||passageColumnFloorSupport||shortSpanFloorSupport))
                 composed=std::min(composed,static_cast<float>(bestSupportDensity));
         }
         return composed;
@@ -416,9 +431,8 @@ public:
                 const double radius=static_cast<double>(std::max(a.radiusSubvoxels,b.radiusSubvoxels))/Q;
                 const double floorThicknessVoxels=Owner&&Owner->CoreVoxelSizeMicrons>0
                     ?1000000.0/Owner->CoreVoxelSizeMicrons:4.0;
-                // A resolved passage bridge extends to a 3.5 m half-width and almost 5 m
-                // below the bore floor. Keep those cells shape-dependent for classification
-                // and streaming even before its bridge ranges have been compiled.
+                // Short support spans can extend to a 3.5 m half-width and almost 5 m
+                // below the bore floor. Keep those cells shape-dependent for classification.
                 const double horizontalExtent=std::max(radius,bridgeHalfWidthVoxels);
                 const double footDepth=std::max(floorThicknessVoxels,bridgeFootDepthVoxels);
                 const double low[3]={
@@ -435,6 +449,19 @@ public:
                 if(overlap)return true;
             }
         }
+        for(const auto& crossing:PassageVoidCrossings)
+        {
+            if(!crossing.needsColumn)continue;
+            const double radius=static_cast<double>(crossing.maximumRadiusSubvoxels)/Q;
+            const double low[3]={crossing.centerXSubvoxels/Q-radius,
+                crossing.centerYSubvoxels/Q-radius,crossing.bottomZSubvoxels/Q};
+            const double high[3]={crossing.centerXSubvoxels/Q+radius,
+                crossing.centerYSubvoxels/Q+radius,crossing.topZSubvoxels/Q};
+            bool overlap=true;
+            for(int axis=0;axis<3;++axis)
+                overlap&=high[axis]>=minimum[axis]&&low[axis]<=maximum[axis];
+            if(overlap)return true;
+        }
         return false;
     }
 
@@ -785,8 +812,10 @@ public:
         if(RoundTunnelsEnabled)
             BuildRoundTunnelPrimitives();
         BuildSpatialBins(LineBinSize);
-        BuildPassageBridgePlan();
         Stats.LocalLineBinSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
+        const auto SharedStage=Clock::now();
+        RebuildSharedFieldPrimitives();
+        Stats.SharedFieldSeconds=std::chrono::duration<double>(Clock::now()-SharedStage).count();
         Stats.ShapeSeconds=std::chrono::duration<double>(Clock::now()-Stage).count();
         Stats.PrimitiveCount=Primitives.size();
         if(Primitives.empty())
@@ -797,6 +826,10 @@ public:
         RockWords.assign(static_cast<size_t>(Size[0])*Size[1]*WordsPerZ,0);
         SurfaceDistanceQ=std::make_unique_for_overwrite<int16[]>(static_cast<size_t>(NodeCount));
         BuildPackedRockIntervals(Stats.RockIntervalLines);
+        // Native density queries for non-heightfield strates use the exact interval
+        // evaluator. Build those native intervals before scanning passage support;
+        // the scan itself still completes before any resolved column is composed.
+        BuildPassageVoidCrossingPlan();
         BuildCandidateBands(Stats.CandidateAxisLines,Stats.CandidateMergeLines,
             Stats.CandidateMergeSeconds);
         if(!BuildGpuVisualDetailNodeSets(InGpuVisualDetailTiles,InCpuVisualDetailTiles,Error))
@@ -820,9 +853,6 @@ public:
             return false;
         }
         Stats.PassageValidationSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
-        Substage=Clock::now();
-        RebuildSharedFieldPrimitives();
-        Stats.SharedFieldSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
         Built=true;
         if(bIncludeFarWorld)BuildFarWorld();
         const uint64 WordBytes=static_cast<uint64>(RockWords.size()+CandidateWords.size())*sizeof(uint64);
@@ -1693,23 +1723,27 @@ public:
     }
 
 private:
-    bool IsPassageBridgeSegment(std::size_t PassageIndex,std::size_t SegmentIndex) const
+    bool IsPassageColumnSegment(std::size_t PassageIndex,std::size_t SegmentIndex) const
     {
-        return std::any_of(PassageBridgeRanges.begin(),PassageBridgeRanges.end(),
-            [PassageIndex,SegmentIndex](const auto& range)
-                {return range.passageIndex==PassageIndex
-                    &&SegmentIndex>=range.firstSegment&&SegmentIndex<=range.lastSegment;});
+        return std::any_of(PassageVoidCrossings.begin(),PassageVoidCrossings.end(),
+            [PassageIndex,SegmentIndex](const auto& crossing)
+                {return crossing.needsColumn&&crossing.passageIndex==PassageIndex
+                    &&SegmentIndex>=crossing.firstSegment&&SegmentIndex<=crossing.lastSegment;});
+    }
+
+    bool IsPassageShortSpanSegment(std::size_t PassageIndex,std::size_t SegmentIndex) const
+    {
+        return std::any_of(PassageVoidCrossings.begin(),PassageVoidCrossings.end(),
+            [PassageIndex,SegmentIndex](const auto& crossing)
+                {return !crossing.needsColumn&&crossing.passageIndex==PassageIndex
+                    &&SegmentIndex>=crossing.firstSegment&&SegmentIndex<=crossing.lastSegment;});
     }
 
     double PassageBridgeDeckOffsetMetres(std::size_t PassageIndex,
         std::size_t SegmentIndex) const
     {
-        for(const auto& range:PassageBridgeRanges)
-        {
-            if(range.passageIndex!=PassageIndex||SegmentIndex>range.lastSegment)continue;
-            if(SegmentIndex>=range.firstSegment)return 0.13;
-        }
-        return 0.20;
+        (void)PassageIndex;(void)SegmentIndex;
+        return 0.13;
     }
 
     double PassageBridgeSignedDistance(std::size_t PassageIndex,std::size_t SegmentIndex,
@@ -1760,6 +1794,109 @@ private:
         return outside+inside;
     }
 
+    double PassageColumnSignedDistance(const FStandalonePassageVoidCrossing& crossing,
+        float X,float Y,float Z) const
+    {
+        if(crossing.maximumRadiusSubvoxels<=0||crossing.topZSubvoxels
+            <=crossing.bottomZSubvoxels)return std::numeric_limits<double>::infinity();
+        constexpr double Q=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
+        const double qPerMetre=Q*1000000.0/std::max<std::uint32_t>(1,
+            ResolvedLayout?ResolvedLayout->coreVoxelSizeMicrometres:250000u);
+        const double qx=static_cast<double>(X)*Q,qy=static_cast<double>(Y)*Q,
+            qz=static_cast<double>(Z)*Q;
+        const double dx=qx-crossing.centerXSubvoxels;
+        const double dy=qy-crossing.centerYSubvoxels;
+        const double maximumRadius=static_cast<double>(crossing.maximumRadiusSubvoxels);
+        const double horizontalSquared=dx*dx+dy*dy;
+        if(horizontalSquared>maximumRadius*maximumRadius)
+            return DeterministicSqrt(horizontalSquared)-maximumRadius;
+        if(qz>crossing.topZSubvoxels)
+            return qz-crossing.topZSubvoxels;
+        if(qz<crossing.bottomZSubvoxels)
+            return crossing.bottomZSubvoxels-qz;
+
+        // The lower-strate route is already walkable in its native field and binds
+        // directly to the passage mouth. Preserve that player capsule as the column
+        // flares into the ground, so the pillar joins the route instead of sealing it.
+        if(ResolvedLayout&&crossing.passageIndex<ResolvedLayout->passages.size()
+            &&qz<crossing.bottomZSubvoxels+18.0*qPerMetre)
+        {
+            const auto& passage=ResolvedLayout->passages[crossing.passageIndex];
+            const auto lower=std::find_if(ResolvedLayout->strates.begin(),
+                ResolvedLayout->strates.end(),[&](const auto& value)
+                    {return value.strateIndex==passage.lowerStrateIndex;});
+            if(lower!=ResolvedLayout->strates.end())
+            {
+                const double capsuleRadius=0.37*qPerMetre;
+                const double capsuleHalfHeight=0.86*qPerMetre;
+                const double capsuleRadiusSquared=capsuleRadius*capsuleRadius;
+                const VoxelForgeCore::ResolvedLayoutAnchorV2* previous=nullptr;
+                for(const auto& anchor:lower->anchors)
+                {
+                    if(anchor.kind!="route_point"||anchor.values.size()<3)continue;
+                    if(previous)
+                    {
+                        const double ax=previous->values[0],ay=previous->values[1];
+                        const double dx=static_cast<double>(anchor.values[0])-ax;
+                        const double dy=static_cast<double>(anchor.values[1])-ay;
+                        const double lengthSquared=dx*dx+dy*dy;
+                        const double t=lengthSquared>0.0?std::clamp(
+                            ((qx-ax)*dx+(qy-ay)*dy)/lengthSquared,0.0,1.0):0.0;
+                        const double routeX=ax+t*dx,routeY=ay+t*dy;
+                        const double routeZ=previous->values[2]+t*(
+                            static_cast<double>(anchor.values[2])-previous->values[2]);
+                        const double routeDx=qx-routeX,routeDy=qy-routeY;
+                        if(routeDx*routeDx+routeDy*routeDy<=capsuleRadiusSquared
+                            &&std::abs(qz-routeZ)<=capsuleHalfHeight)
+                            return maximumRadius+qPerMetre;
+                    }
+                    previous=&anchor;
+                }
+            }
+        }
+
+        const double height=static_cast<double>(crossing.topZSubvoxels
+            -crossing.bottomZSubvoxels);
+        const double t=std::clamp((crossing.topZSubvoxels-qz)/height,0.0,1.0);
+        const auto smoothStep=[](double value)
+        {
+            value=std::clamp(value,0.0,1.0);
+            return value*value*(3.0-2.0*value);
+        };
+        const float z=static_cast<float>(Z);
+        const float scaledZ=z*0.12f;
+        const float driftX=VF_FieldSurfaceRelief(0.0f,0.0f,scaledZ,
+            static_cast<std::uint32_t>(Owner?Owner->Seed:0)^0x434f4c58u);
+        const float driftY=VF_FieldSurfaceRelief(0.0f,0.0f,scaledZ,
+            static_cast<std::uint32_t>(Owner?Owner->Seed:0)^0x434f4c59u);
+        const double axisX=crossing.centerXSubvoxels
+            +std::clamp(static_cast<double>(driftX),-1.0,1.0)*0.35*qPerMetre;
+        const double axisY=crossing.centerYSubvoxels
+            +std::clamp(static_cast<double>(driftY),-1.0,1.0)*0.35*qPerMetre;
+        const double centerDx=qx-axisX,centerDy=qy-axisY;
+        const double radialDistance=DeterministicSqrt(centerDx*centerDx+centerDy*centerDy);
+        const float broadRelief=VF_FieldSurfaceRelief(X*0.12f,Y*0.12f,Z*0.12f,
+            static_cast<std::uint32_t>(Owner?Owner->Seed:0)^0x434f4c52u);
+        const float surfaceRelief=VF_FieldSurfaceRelief(X,Y,Z,
+            static_cast<std::uint32_t>(Owner?Owner->Seed:0)^0x434f4c53u);
+        const double baseFlare=6.0*qPerMetre*smoothStep((t-0.82)/0.18);
+        const double ceilingFlare=2.0*qPerMetre*(1.0-smoothStep(t/0.075));
+        const double irregularity=1.25*qPerMetre
+            +std::clamp(static_cast<double>(broadRelief),-1.0,1.0)*1.10*qPerMetre
+            +std::clamp(static_cast<double>(surfaceRelief),-1.0,1.0)*0.35*qPerMetre;
+        const double radius=static_cast<double>(crossing.minimumRadiusSubvoxels)
+            +std::max(0.15*qPerMetre,irregularity)+baseFlare+ceilingFlare;
+        const double radialDistanceField=radialDistance-radius;
+        const double topDistance=qz-crossing.topZSubvoxels;
+        const double bottomDistance=crossing.bottomZSubvoxels-qz;
+        const double verticalDistance=std::max(topDistance,bottomDistance);
+        const double outside=DeterministicSqrt(
+            std::max(radialDistanceField,0.0)*std::max(radialDistanceField,0.0)
+            +std::max(verticalDistance,0.0)*std::max(verticalDistance,0.0));
+        const double inside=std::min(std::max(radialDistanceField,verticalDistance),0.0);
+        return outside+inside;
+    }
+
     float NativePassageDensityAt(float X,float Y,float Z) const
     {
         float density=0.0f;
@@ -1775,33 +1912,25 @@ private:
         return ApplyResolvedStrateBoundaryBand(density,X,Y,Z);
     }
 
-    void BuildPassageBridgePlan()
+    void BuildPassageVoidCrossingPlan()
     {
-        PassageBridgeRanges.clear();
+        PassageVoidCrossings.clear();
         if(!Owner||!ResolvedLayout||ResolvedLayout->passages.empty()
-            ||!Owner->PassageBridgeCache)return;
-        auto& cache=*Owner->PassageBridgeCache;
+            ||!Owner->PassageVoidCrossingCache)return;
+        auto& cache=*Owner->PassageVoidCrossingCache;
         std::lock_guard<std::mutex> lock(cache.mutex);
-        const auto cached=cache.byLayout.find(ResolvedLayout->stableIdentity);
+        const std::string cacheKey=ResolvedLayout->stableIdentity+"/passage-void-columns-v1";
+        const auto cached=cache.byLayout.find(cacheKey);
         if(cached!=cache.byLayout.end())
-        {PassageBridgeRanges=cached->second;return;}
+        {PassageVoidCrossings=cached->second;return;}
 
         constexpr double Q=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
         const double qPerMetre=Q*1000000.0/std::max<std::uint32_t>(1,
             ResolvedLayout->coreVoxelSizeMicrometres);
-        const auto inSurfaceWorldStratum=[&](double zSubvoxels)
-        {
-            const double zMicrometres=zSubvoxels
-                *ResolvedLayout->coreVoxelSizeMicrometres/Q;
-            return std::any_of(ResolvedLayout->strates.begin(),ResolvedLayout->strates.end(),
-                [zMicrometres](const auto& stratum)
-                {return stratum.generatorKind=="SurfaceWorld"
-                    &&zMicrometres>=stratum.interiorBottomMicrometres
-                    &&zMicrometres<stratum.interiorTopMicrometres;});
-        };
         constexpr std::array<std::array<double,2>,5> supportOffsets{{
             {{0.0,0.0}},{{0.45,0.0}},{{-0.45,0.0}},{{0.0,0.45}},{{0.0,-0.45}}}};
         constexpr std::array<double,2> supportDepthsMetres{{0.125,0.25}};
+        constexpr double shortSpanMaximumMetres=12.5; // 2.5 x the 5 m legacy support thickness.
         struct FPathSample
         {
             std::size_t segment=0;
@@ -1818,14 +1947,10 @@ private:
                 for(const double depth:supportDepthsMetres)
                 {
                     const double sampleZ=floorQ-depth*qPerMetre;
-                    // Bridge spans address the measured SurfaceWorld void. Other native
-                    // strata retain their own route/cave composition and are excluded here.
-                    if(!inSurfaceWorldStratum(sampleZ)){hasSolid=true;break;}
-                    float density=1.0f;
-                    if(!NativeSurfaceDensityAt(
+                    const float density=NativePassageDensityAt(
                         static_cast<float>((point[0]+offset[0]*qPerMetre)/Q),
                         static_cast<float>((point[1]+offset[1]*qPerMetre)/Q),
-                        static_cast<float>(sampleZ/Q),density))continue;
+                        static_cast<float>(sampleZ/Q));
                     if(density<0.0f){hasSolid=true;break;}
                 }
                 supported+=hasSolid;
@@ -1874,9 +1999,10 @@ private:
                 const std::size_t gapBegin=cursor;
                 while(cursor<samples.size()&&!samples[cursor].nativeSupported)++cursor;
                 const std::size_t gapEnd=cursor-1;
-                if(gapBegin==0||cursor>=samples.size())continue;
+                const std::size_t startSample=gapBegin>0?gapBegin-1:gapBegin;
+                const std::size_t endSample=cursor<samples.size()?cursor:samples.size()-1;
                 double gapLength=0.0;
-                for(std::size_t index=gapBegin;index<=gapEnd;++index)
+                for(std::size_t index=startSample+1;index<=endSample;++index)
                 {
                     const auto& a=samples[index-1].point;
                     const auto& b=samples[index].point;
@@ -1884,25 +2010,105 @@ private:
                     gapLength+=DeterministicSqrt(dx*dx+dy*dy+dz*dz)/qPerMetre;
                 }
                 if(gapLength<1.0)continue;
-                FStandalonePassageBridgeRange range;
-                range.passageIndex=passageIndex;
-                range.firstSegment=samples[gapBegin-1].segment;
-                range.lastSegment=samples[cursor].segment;
-                range.unsupportedSamples=gapEnd-gapBegin+1;
-                range.unsupportedLengthMetres=gapLength;
-                range.startPoint=samples[gapBegin-1].point;
-                range.endPoint=samples[cursor].point;
-                PassageBridgeRanges.push_back(range);
-                std::printf("[PassageRockBridgePlan] id=%s first_segment=%zu last_segment=%zu unsupported_samples=%llu gap_length_m=%.3f connected_start=1 connected_end=1 width_m=6.000 thickness_m=3.000..5.000 status=PLANNED\n",
-                    passage.stableId.c_str(),range.firstSegment,range.lastSegment,
-                    static_cast<unsigned long long>(range.unsupportedSamples),gapLength);
+                FStandalonePassageVoidCrossing crossing;
+                crossing.passageIndex=passageIndex;
+                crossing.firstSegment=samples[startSample].segment;
+                crossing.lastSegment=samples[endSample].segment;
+                crossing.unsupportedSamples=gapEnd-gapBegin+1;
+                crossing.unsupportedLengthMetres=gapLength;
+                crossing.startPoint=samples[startSample].point;
+                crossing.endPoint=samples[endSample].point;
+                crossing.connectedAtStart=gapBegin>0&&samples[startSample].nativeSupported;
+                crossing.connectedAtEnd=cursor<samples.size()&&samples[endSample].nativeSupported;
+                crossing.needsColumn=gapLength>shortSpanMaximumMetres;
+                if(crossing.needsColumn&&passage.controlPoints.size()>1)
+                    crossing.lastSegment=std::min(crossing.lastSegment+1,
+                        passage.controlPoints.size()-2);
+                if(crossing.needsColumn)
+                {
+                    std::int64_t sumX=0,sumY=0;
+                    std::uint64_t centerSamples=0;
+                    for(std::size_t index=gapBegin;index<=gapEnd;++index)
+                    {
+                        sumX+=static_cast<std::int64_t>(std::llround(samples[index].point[0]));
+                        sumY+=static_cast<std::int64_t>(std::llround(samples[index].point[1]));
+                        ++centerSamples;
+                    }
+                    crossing.centerXSubvoxels=centerSamples>0
+                        ?static_cast<std::int64_t>(std::llround(static_cast<double>(sumX)/centerSamples)):0;
+                    crossing.centerYSubvoxels=centerSamples>0
+                        ?static_cast<std::int64_t>(std::llround(static_cast<double>(sumY)/centerSamples)):0;
+                    for(const auto& stratum:ResolvedLayout->strates)
+                        if(stratum.strateIndex==passage.upperStrateIndex
+                            &&stratum.generatorKind=="FloatingIslands")
+                            for(const auto& anchor:stratum.anchors)
+                                if(anchor.kind=="passage_anchor"&&anchor.values.size()>=2)
+                                {
+                                    crossing.centerXSubvoxels=anchor.values[0];
+                                    crossing.centerYSubvoxels=anchor.values[1];
+                                    break;
+                                }
+                    double maximumOffsetSubvoxels=0.0;
+                    double maximumBoreSubvoxels=0.0;
+                    for(std::size_t index=startSample;index<=endSample;++index)
+                    {
+                        const auto& point=samples[index].point;
+                        const double dx=point[0]-crossing.centerXSubvoxels;
+                        const double dy=point[1]-crossing.centerYSubvoxels;
+                        maximumOffsetSubvoxels=std::max(maximumOffsetSubvoxels,
+                            DeterministicSqrt(dx*dx+dy*dy));
+                        maximumBoreSubvoxels=std::max(maximumBoreSubvoxels,point[3]);
+                    }
+                    const double maximumOffsetMetres=maximumOffsetSubvoxels/qPerMetre;
+                    const double maximumBoreMetres=maximumBoreSubvoxels/qPerMetre;
+                    const double minimumRadiusMetres=maximumOffsetMetres+maximumBoreMetres+2.0;
+                    const double nominalRadiusMetres=minimumRadiusMetres+1.25;
+                    crossing.maximumRouteOffsetMetres=maximumOffsetMetres;
+                    crossing.maximumBoreRadiusMetres=maximumBoreMetres;
+                    crossing.minimumRadiusSubvoxels=static_cast<std::int64_t>(std::ceil(
+                        minimumRadiusMetres*qPerMetre));
+                    crossing.nominalRadiusSubvoxels=static_cast<std::int64_t>(std::llround(
+                        nominalRadiusMetres*qPerMetre));
+                    crossing.maximumRadiusSubvoxels=crossing.minimumRadiusSubvoxels
+                        +static_cast<std::int64_t>(std::ceil(11.25*qPerMetre));
+                    const double startZ=crossing.startPoint[2];
+                    const double endZ=crossing.endPoint[2];
+                    crossing.topZSubvoxels=static_cast<std::int64_t>(std::llround(
+                        std::max(startZ,endZ)+5.0*qPerMetre));
+                    crossing.bottomZSubvoxels=static_cast<std::int64_t>(std::llround(
+                        std::min(startZ,endZ)-6.0*qPerMetre));
+                }
+                PassageVoidCrossings.push_back(crossing);
+                if(crossing.needsColumn)
+                {
+                    const double coreRadius=crossing.nominalRadiusSubvoxels/qPerMetre;
+                    const double minimumWall=coreRadius-crossing.maximumRouteOffsetMetres
+                        -crossing.maximumBoreRadiusMetres;
+                    std::printf("[PassageVoidColumnPlan] id=%s segments=%zu..%zu unsupported_samples=%llu span_m=%.3f threshold_m=%.3f connected=%d/%d axis_m=(%.3f,%.3f) z_m=%.3f..%.3f route_radius_m=%.3f bore_radius_m=%.3f min_radius_m=%.3f nominal_radius_m=%.3f max_radius_m=%.3f nominal_wall_m=%.3f flare_m=6.000 status=%s\n",
+                        passage.stableId.c_str(),crossing.firstSegment,crossing.lastSegment,
+                        static_cast<unsigned long long>(crossing.unsupportedSamples),gapLength,
+                        shortSpanMaximumMetres,static_cast<int>(crossing.connectedAtStart),
+                        static_cast<int>(crossing.connectedAtEnd),
+                        crossing.centerXSubvoxels/qPerMetre,crossing.centerYSubvoxels/qPerMetre,
+                        crossing.topZSubvoxels/qPerMetre,crossing.bottomZSubvoxels/qPerMetre,
+                        crossing.maximumRouteOffsetMetres,crossing.maximumBoreRadiusMetres,
+                        crossing.minimumRadiusSubvoxels/qPerMetre,coreRadius,
+                        crossing.maximumRadiusSubvoxels/qPerMetre,minimumWall,
+                        crossing.connectedAtStart&&crossing.connectedAtEnd?"PLANNED":"UNATTACHED");
+                }
+                else
+                    std::printf("[PassageShortGroundedSpanPlan] id=%s segments=%zu..%zu span_m=%.3f threshold_m=%.3f connected=%d/%d width_m=6.000 thickness_m=3.000..5.000 status=%s\n",
+                        passage.stableId.c_str(),crossing.firstSegment,crossing.lastSegment,
+                        gapLength,shortSpanMaximumMetres,static_cast<int>(crossing.connectedAtStart),
+                        static_cast<int>(crossing.connectedAtEnd),
+                        crossing.connectedAtStart&&crossing.connectedAtEnd?"PLANNED":"UNATTACHED");
             }
-            if(std::none_of(PassageBridgeRanges.begin(),PassageBridgeRanges.end(),
+            if(std::none_of(PassageVoidCrossings.begin(),PassageVoidCrossings.end(),
                 [passageIndex](const auto& range){return range.passageIndex==passageIndex;}))
-                std::printf("[PassageRockBridgePlan] id=%s spans=0 status=NOT_REQUIRED\n",
+                std::printf("[PassageVoidColumnPlan] id=%s crossings=0 status=NOT_REQUIRED\n",
                     passage.stableId.c_str());
         }
-        cache.byLayout.emplace(ResolvedLayout->stableIdentity,PassageBridgeRanges);
+        cache.byLayout.emplace(cacheKey,PassageVoidCrossings);
     }
 
     static uint64 PackLatticeKey(int32 X,int32 Y,int32 Z)
@@ -6151,7 +6357,7 @@ private:
     std::vector<FFarConnectorSegment> FarConnectorSegments;
     std::unordered_map<FBinKey,std::vector<uint32>,FBinHash> FarConnectorSpatialBins;
     std::vector<FEditBrush> EditBrushes;
-    std::vector<FStandalonePassageBridgeRange> PassageBridgeRanges;
+    std::vector<FStandalonePassageVoidCrossing> PassageVoidCrossings;
     std::array<FAxisBins,3> AxisBins;
     std::unordered_map<FBinKey,FBinItems,FBinHash> SpatialBins;
     std::unordered_map<FBinKey,FBinItems,FBinHash> CriticalAirBins;