wip: L176 step 3 in progress (unverified, saved after machine crash)

Bore carves air only, stamp last, chambers/exemptions/plane fit removed.
Seed 0: seams 0, no solid over host air (control detected); pad audit 0/6
(surface landing lacks support - step 4). 16-seed sweep interrupted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011g9Ez42ZNqQGjigc4FWDih

Standalone/Core/src/ResolvedLayoutInternal.h

@@ -653,22 +653,7 @@ namespace
                 <<"],\"mouth_radius_q\":"<<p.mouthRadiusSubvoxels
                 <<",\"mid_radius_q\":"<<p.midRadiusSubvoxels
                 <<",\"end_run_q\":"<<p.endRunSubvoxels
-                <<",\"floor_profile_includes_landing_chambers\":"
-                <<(p.floorProfileIncludesLandingChambers?"true":"false");
-            const auto writeLandingChamber=[&](const char* name,
-                const ResolvedLayoutPassageLandingChamberV1& chamber)
-            {
-                out<<",\""<<name<<"\":{\"floor_center_q\":["
-                    <<chamber.floorCenterSubvoxels[0]<<','
-                    <<chamber.floorCenterSubvoxels[1]<<','
-                    <<chamber.floorCenterSubvoxels[2]<<"],\"floor_gradient_q16\":["
-                    <<chamber.floorGradientQ16[0]<<','<<chamber.floorGradientQ16[1]
-                    <<"],\"radius_q\":"<<chamber.radiusSubvoxels
-                    <<",\"clear_height_q\":"<<chamber.clearHeightSubvoxels<<'}';
-            };
-            writeLandingChamber("upper_landing_chamber",p.upperLandingChamber);
-            writeLandingChamber("lower_landing_chamber",p.lowerLandingChamber);
-            out<<",\"control_points\":[";
+                <<",\"control_points\":[";
             for(std::size_t j=0;j<p.controlPoints.size();++j)
             {
                 if(j)out<<',';const auto& point=p.controlPoints[j];
@@ -1269,62 +1254,6 @@ bool ResolvedLayoutSnapshotV3::validate(ResolvedLayoutValidationModeV3 mode,
         if(!insideContent(*upper,passage.upperMouthSubvoxels)
             ||!insideContent(*lower,passage.lowerMouthSubvoxels))
             add("passage_mouth_content",passage.stableId+" mouth is outside its owned content band");
-        const auto validateLandingChamber=[&](
-            const ResolvedLayoutPassageLandingChamberV1& chamber,
-            const ResolvedLayoutStratumV2& host,
-            const std::array<std::int64_t,3>& mouth,const char* side)
-        {
-            const double playerCenterHeight=(side==std::string_view("upper")
-                &&host.generatorKind=="SurfaceWorld")?0.98:1.13;
-            const std::int64_t playerCenterHeightQ=static_cast<std::int64_t>(
-                std::llround(playerCenterHeight*WorldAssemblySubvoxelsPerVoxel
-                    *1000000.0/std::max<std::uint32_t>(1,coreVoxelSizeMicrometres)));
-            if(chamber.floorCenterSubvoxels[0]!=mouth[0]
-                ||chamber.floorCenterSubvoxels[1]!=mouth[1]
-                ||chamber.floorCenterSubvoxels[2]+playerCenterHeightQ!=mouth[2]
-                ||chamber.radiusSubvoxels<=0
-                ||chamber.clearHeightSubvoxels<=0
-                ||chamber.radiusSubvoxels<passage.mouthRadiusSubvoxels
-                ||chamber.clearHeightSubvoxels<static_cast<std::int64_t>(
-                    std::llround(2.2*WorldAssemblySubvoxelsPerVoxel*1000000.0
-                        /std::max<std::uint32_t>(1,coreVoxelSizeMicrometres))))
-            {
-                add("passage_landing_chamber",passage.stableId+" "+side
-                    +" landing chamber has invalid floor, radius, or capsule clearance");
-                return;
-            }
-            const std::uint64_t gradientSquared=static_cast<std::uint64_t>(
-                chamber.floorGradientQ16[0]*chamber.floorGradientQ16[0]
-                +chamber.floorGradientQ16[1]*chamber.floorGradientQ16[1]);
-            const std::int64_t gradientMagnitude=static_cast<std::int64_t>(
-                PassageIsqrt(gradientSquared));
-            if(gradientMagnitude>17560)
-                add("passage_landing_grade",passage.stableId+" "+side
-                    +" landing chamber floor exceeds 15 degrees");
-            const std::int64_t planeReachQ=static_cast<std::int64_t>(
-                (chamber.radiusSubvoxels*gradientMagnitude+65535)/65536);
-            const std::int64_t shellQ=static_cast<std::int64_t>(std::llround(
-                0.75*WorldAssemblySubvoxelsPerVoxel*1000000.0
-                    /std::max<std::uint32_t>(1,coreVoxelSizeMicrometres)));
-            const auto qToUm=[&](std::int64_t q)
-            {return q*static_cast<std::int64_t>(coreVoxelSizeMicrometres)
-                /WorldAssemblySubvoxelsPerVoxel;};
-            if(!host.content.presentInCurrentField
-                ||qToUm(chamber.floorCenterSubvoxels[2]-planeReachQ-shellQ)
-                    <host.content.bottomMicrometres
-                ||qToUm(chamber.floorCenterSubvoxels[2]+planeReachQ
-                    +chamber.clearHeightSubvoxels+shellQ)
-                    >host.content.topMicrometres)
-                add("passage_landing_content",passage.stableId+" "+side
-                    +" landing chamber or plain shell leaves its host content band");
-        };
-        if(upper&&lower)
-        {
-            validateLandingChamber(passage.upperLandingChamber,*upper,
-                passage.upperMouthSubvoxels,"upper");
-            validateLandingChamber(passage.lowerLandingChamber,*lower,
-                passage.lowerMouthSubvoxels,"lower");
-        }
         if(passage.controlPoints.size()<2)continue;
         const std::int64_t PlayerCenterAboveFloorQ=coreVoxelSizeMicrometres>0
             ?static_cast<std::int64_t>(std::llround(1.13*WorldAssemblySubvoxelsPerVoxel
@@ -2113,27 +2042,10 @@ std::optional<ResolvedLayoutSnapshotV3> ResolvedLayoutSnapshotV3::FromJson(
         p.placementRadiusSubvoxels=LayoutInt(v,"placement_radius_q");
         p.mouthRadiusSubvoxels=LayoutInt(v,"mouth_radius_q");p.midRadiusSubvoxels=LayoutInt(v,"mid_radius_q");
         p.endRunSubvoxels=LayoutInt(v,"end_run_q");
-        p.floorProfileIncludesLandingChambers=
-            LayoutBool(v,"floor_profile_includes_landing_chambers");
         const auto& upper=v.Get("upper_mouth_q").AsArray();
         const auto& lower=v.Get("lower_mouth_q").AsArray();
         for(std::size_t axis=0;axis<3&&axis<upper.size();++axis)p.upperMouthSubvoxels[axis]=upper[axis].Integer();
         for(std::size_t axis=0;axis<3&&axis<lower.size();++axis)p.lowerMouthSubvoxels[axis]=lower[axis].Integer();
-        const auto readLandingChamber=[&](const char* key,
-            ResolvedLayoutPassageLandingChamberV1& chamber)
-        {
-            const auto& value=v.Get(key);
-            const auto& center=value.Get("floor_center_q").AsArray();
-            const auto& gradient=value.Get("floor_gradient_q16").AsArray();
-            for(std::size_t axis=0;axis<3&&axis<center.size();++axis)
-                chamber.floorCenterSubvoxels[axis]=center[axis].Integer();
-            for(std::size_t axis=0;axis<2&&axis<gradient.size();++axis)
-                chamber.floorGradientQ16[axis]=gradient[axis].Integer();
-            chamber.radiusSubvoxels=LayoutInt(value,"radius_q");
-            chamber.clearHeightSubvoxels=LayoutInt(value,"clear_height_q");
-        };
-        readLandingChamber("upper_landing_chamber",p.upperLandingChamber);
-        readLandingChamber("lower_landing_chamber",p.lowerLandingChamber);
         for(const auto& q:v.Get("control_points").AsArray())
         {
             ResolvedLayoutPassagePointV1 point;const auto& position=q.Get("position_q").AsArray();
@@ -2940,7 +2852,7 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
         std::size_t mouthIndex,bool lowerSide,
         const std::array<std::int64_t,2>& authoredRouteTangentQ16,
         std::int64_t authoredFloorSlopeQ16,const FPoint& mouthFloorPoint,
-        std::int64_t chamberRadiusMicrometres)
+        std::int64_t landingRadiusMicrometres)
     {
         constexpr std::array<std::array<std::int64_t,2>,16> DirectionsQ16={{
             {{65536,0}},{{60547,25080}},{{46341,46341}},{{25080,60547}},
@@ -2959,7 +2871,7 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
                 /(65536ll*65536ll));
             constexpr std::int64_t MouthClearanceProbeExtent=48000000;
             const std::int64_t firstClearanceProbe=std::max<std::int64_t>(
-                2000000,chamberRadiusMicrometres+1000000);
+                2000000,landingRadiusMicrometres+1000000);
             for(std::int64_t distance=firstClearanceProbe;
                 distance<=MouthClearanceProbeExtent;distance+=2000000)
             {
@@ -3057,13 +2969,13 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
         bool lowerSide,FPoint& point,std::array<std::int64_t,2>& routeTangentQ16,
         std::int64_t& floorSlopeQ16)
     {
-        const auto& chamber=lowerSide?passage.lowerLandingChamber
-            :passage.upperLandingChamber;
-        for(std::size_t axis=0;axis<3;++axis)
-            point[axis]=qToMicrometres(chamber.floorCenterSubvoxels[axis]);
         if(passage.controlPoints.size()<2)return false;
         const std::size_t mouthIndex=lowerSide
             ?std::min(passage.lowerMouthControlIndex,passage.controlPoints.size()-1):0;
+        const auto& mouth=lowerSide?passage.lowerMouthSubvoxels
+            :passage.upperMouthSubvoxels;
+        point[0]=qToMicrometres(mouth[0]);
+        point[1]=qToMicrometres(mouth[1]);
         const std::size_t tangentIndex=lowerSide
             ?(mouthIndex>0?mouthIndex-1:1):1;
         // The lower arrival continues from the previous passage point through its
@@ -3080,26 +2992,23 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
         if(tangentLength<=0)return false;
         routeTangentQ16={tx*65536/tangentLength,ty*65536/tangentLength};
         const auto& mouthControl=passage.controlPoints[mouthIndex];
-        const std::int64_t mouthFloor=chamber.floorCenterSubvoxels[2];
+        const std::int64_t mouthFloor=mouthControl.positionSubvoxels[2]
+            -mouthControl.radiusSubvoxels;
         point[2]=qToMicrometres(mouthFloor);
-        floorSlopeQ16=(chamber.floorGradientQ16[0]*routeTangentQ16[0]
-            +chamber.floorGradientQ16[1]*routeTangentQ16[1])/65536;
+        floorSlopeQ16=0;
         const auto authoredRouteTangentQ16=routeTangentQ16;
         routeTangentQ16=chooseMouthRouteTangent(passage,mouthIndex,lowerSide,
             authoredRouteTangentQ16,floorSlopeQ16,point,
-            qToMicrometres(chamber.radiusSubvoxels));
-        floorSlopeQ16=(chamber.floorGradientQ16[0]*routeTangentQ16[0]
-            +chamber.floorGradientQ16[1]*routeTangentQ16[1])/65536;
+            qToMicrometres(ResolvedLayoutPassageLandingDiscRadiusSubvoxels(
+                passage.mouthRadiusSubvoxels,layout.coreVoxelSizeMicrometres)));
         const std::int64_t offsetDirection=lowerSide?1:-1;
         const std::int64_t portOffset=std::max<std::int64_t>(0,
-            qToMicrometres(chamber.radiusSubvoxels)-LandingConnectorBoreRadius);
+            qToMicrometres(ResolvedLayoutPassageLandingDiscRadiusSubvoxels(
+                passage.mouthRadiusSubvoxels,layout.coreVoxelSizeMicrometres))
+                -LandingConnectorBoreRadius);
         point[0]+=offsetDirection*routeTangentQ16[0]*portOffset/65536;
         point[1]+=offsetDirection*routeTangentQ16[1]*portOffset/65536;
-        point[2]=qToMicrometres(mouthFloor)
-            +(chamber.floorGradientQ16[0]*(point[0]
-                -qToMicrometres(chamber.floorCenterSubvoxels[0]))
-                +chamber.floorGradientQ16[1]*(point[1]
-                    -qToMicrometres(chamber.floorCenterSubvoxels[1])))/65536;
+        point[2]=qToMicrometres(mouthFloor);
         return true;
     };
     FPoint routeStart{},routeEnd{};
@@ -3932,7 +3841,7 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
     const auto arrivalPoint=routeStart;
     FPoint previousPoint=arrivalPoint;
     std::int64_t previousProfileDistance=0;
-    std::string previousAnchor=arrivalPassage->stableId+"/lower-landing-chamber";
+    std::string previousAnchor=arrivalPassage->stableId+"/lower-landing-pad";
     for(std::size_t nodeIndex=0;nodeIndex<nodes.size();++nodeIndex)
     {
         const auto& node=nodes[nodeIndex];
@@ -3950,7 +3859,7 @@ bool PlanResolvedCavernNetworkV1(const ResolvedLayoutSnapshotV3& layout,
     {
         const std::string departureEdgeId=routePrefix+"departure-edge";
         auto edge=makeEdge(departureEdgeId,
-            departurePassage->stableId+"/upper-landing-chamber",
+            departurePassage->stableId+"/upper-landing-pad",
             routeEnd,nodes.back(),
             std::min(selectedBoreRadius(departureEdgeId),LandingConnectorBoreRadius),
             totalRouteLength,nodes.back().floorProfileDistanceMicrometres);
@@ -4375,17 +4284,21 @@ static FPassageTubeSelfOverlapCensus CensusPassageTubeSelfOverlaps(
             passage.mouthRadiusSubvoxels+qPerMetre)+qPerMetre);
     const std::int64_t landingDiscRadius=ResolvedLayoutPassageLandingDiscRadiusSubvoxels(
         passage.mouthRadiusSubvoxels,coreVoxelSizeMicrometres);
-    const auto overlapsLandingColumn=[&](
-        const ResolvedLayoutPassageLandingChamberV1& chamber,
-        const std::array<std::int64_t,3>& landingMouth,
-        const std::array<double,3>& center)
+    const std::int64_t landingHeadroom=static_cast<std::int64_t>(
+        std::llround(4.5*qPerMetre));
+    const auto overlapsLandingColumn=[&](bool upper,const std::array<double,3>& center)
     {
-        if(chamber.radiusSubvoxels<=0||chamber.clearHeightSubvoxels<=0)return false;
-        const double floor=static_cast<double>(chamber.floorCenterSubvoxels[2]);
-        const double ceiling=floor+static_cast<double>(chamber.clearHeightSubvoxels);
+        if(landingDiscRadius<=0||passage.controlPoints.size()<2)return false;
+        const std::size_t endpointIndex=upper?0:
+            std::min(passage.lowerMouthControlIndex,passage.controlPoints.size()-1);
+        const auto& endpoint=passage.controlPoints[endpointIndex];
+        const double floor=static_cast<double>(endpoint.positionSubvoxels[2]
+            -endpoint.radiusSubvoxels);
+        const double ceiling=floor+static_cast<double>(landingHeadroom);
         if(center[2]<floor||center[2]>ceiling)return false;
+        const auto& mouth=upper?passage.upperMouthSubvoxels:passage.lowerMouthSubvoxels;
         return IsInsideResolvedLayoutPassageLandingDiscV1(
-            {landingMouth[0],landingMouth[1]},landingDiscRadius,center[0],center[1]);
+            {mouth[0],mouth[1]},landingDiscRadius,center[0],center[1]);
     };
     for(std::size_t segment=0;segment+1<passage.controlPoints.size();++segment)
     {
@@ -4404,10 +4317,8 @@ static FPassageTubeSelfOverlapCensus CensusPassageTubeSelfOverlaps(
             if(routeDistance<=endRun||horizontalAlong.back()-routeDistance<=endRun)continue;
             const std::array<double,3> center={a[0]+t*(b[0]-a[0]),
                 a[1]+t*(b[1]-a[1]),a[2]+t*(b[2]-a[2])};
-            upperColumnViolation|=overlapsLandingColumn(passage.upperLandingChamber,
-                passage.upperMouthSubvoxels,center);
-            lowerColumnViolation|=overlapsLandingColumn(passage.lowerLandingChamber,
-                passage.lowerMouthSubvoxels,center);
+            upperColumnViolation|=overlapsLandingColumn(true,center);
+            lowerColumnViolation|=overlapsLandingColumn(false,center);
             if(upperColumnViolation&&lowerColumnViolation)break;
         }
         if((upperColumnViolation||lowerColumnViolation)
@@ -4867,72 +4778,6 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
                                 }
                 }
             }
-            // Reserve each landing envelope inside its host band before building h(s).
-            // SurfaceWorld can raise its floor by at most the 4.5 m headroom allowance,
-            // so include that bounded rise as well as the grade reach and floor shell.
-            constexpr std::int64_t MaximumLandingGradeQ16=17560;
-            const std::int64_t landingRadius=mouthRadius+3*qPerMetre;
-            const std::int64_t landingClearHeight=static_cast<std::int64_t>(
-                std::llround(4.5*qPerMetre));
-            const std::int64_t landingShell=static_cast<std::int64_t>(
-                std::llround(0.75*qPerMetre));
-            const std::int64_t landingPlaneReach=(landingRadius
-                *MaximumLandingGradeQ16+65535)/65536;
-            const std::array<std::int64_t,3> upperMouthBeforeBandFit=upperMouth;
-            const std::array<std::int64_t,3> lowerMouthBeforeBandFit=lowerMouth;
-            const auto fitMouth=[&](std::array<std::int64_t,3>& mouth,
-                const ResolvedLayoutStratumV2& host,std::int64_t playerHeightQ,
-                const char* side)
-            {
-                if(!host.content.presentInCurrentField)return true;
-                const std::int64_t minimumFloor=contentZQ(host.content.bottomMicrometres)
-                    +landingPlaneReach+landingShell;
-                const std::int64_t nativeFloorRise=host.generatorKind=="SurfaceWorld"
-                    ?landingClearHeight:0;
-                const std::int64_t maximumFloor=contentZQ(host.content.topMicrometres)
-                    -landingPlaneReach-landingShell-landingClearHeight-nativeFloorRise;
-                if(maximumFloor<minimumFloor)
-                {error=passage.stableId+" "+side
-                    +" landing chamber envelope is taller than its host content band";return false;}
-                const std::int64_t requestedFloor=mouth[2]-playerHeightQ;
-                const std::int64_t fittedFloor=std::clamp(requestedFloor,
-                    minimumFloor,maximumFloor);
-                if(fittedFloor!=requestedFloor)
-                {
-                    mouth[2]=fittedFloor+playerHeightQ;
-                    std::printf("[PassageLandingChamberPlacement] id=%s side=%s floor_shift_m=%.3f grade_bound_deg=15.000 clear_height_m=4.500 shell_m=0.750 status=PASS\n",
-                        passage.stableId.c_str(),side,
-                        (fittedFloor-requestedFloor)/static_cast<double>(qPerMetre));
-                }
-                return true;
-            };
-            if(!fitMouth(upperMouth,upper,upperPlayerCenterAboveFloorQ,"upper")
-                ||!fitMouth(lowerMouth,lower,playerCenterAboveFloorQ,"lower"))return false;
-            const auto bindFittedMouthAnchor=[&](
-                const ResolvedLayoutStratumV2& host,
-                const std::array<std::int64_t,3>& before,
-                const std::array<std::int64_t,3>& after,const char* side)
-            {
-                if(before==after)return;
-                auto mutableHost=std::find_if(layout.strates.begin(),layout.strates.end(),
-                    [&](const auto& stratum)
-                    {return stratum.strateIndex==host.strateIndex;});
-                if(mutableHost!=layout.strates.end())
-                    for(auto& anchor:mutableHost->anchors)
-                        if((anchor.kind=="passage_arrival"
-                                ||anchor.kind=="passage_departure")
-                            &&anchor.values.size()>=3
-                            &&anchor.values[0]==after[0]
-                            &&anchor.values[1]==after[1])
-                        {
-                            anchor.values[2]=after[2];
-                            std::printf("[PassageLandingChamberArrivalBinding] id=%s side=%s anchor=%s status=PASS\n",
-                                passage.stableId.c_str(),side,anchor.stableId.c_str());
-                            break;
-                        }
-            };
-            bindFittedMouthAnchor(upper,upperMouthBeforeBandFit,upperMouth,"upper");
-            bindFittedMouthAnchor(lower,lowerMouthBeforeBandFit,lowerMouth,"lower");
             if(!radialWithin(upperMouth,placementRadius)||!radialWithin(lowerMouth,placementRadius))
             {error=passage.stableId+" route mouth is outside the resolved PassageConfig.DistanceMax radius";return false;}
             passage.upperMouthSubvoxels=upperMouth;passage.lowerMouthSubvoxels=lowerMouth;
@@ -6007,18 +5852,18 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
             passage.controlPoints[lowerMouthIndex].positionSubvoxels[2]=lowerMouth[2]
                 +passage.controlPoints[lowerMouthIndex].radiusSubvoxels
                     -playerCenterAboveFloorQ;
-            std::vector<VoxelForgeCore::PassageSpline::FPoint> chamberFloorControls;
-            std::vector<double> chamberFloorProfile;
-            chamberFloorControls.reserve(passage.controlPoints.size());
-            chamberFloorProfile.reserve(passage.controlPoints.size());
+            std::vector<VoxelForgeCore::PassageSpline::FPoint> endpointFloorControls;
+            std::vector<double> endpointFloorProfile;
+            endpointFloorControls.reserve(passage.controlPoints.size());
+            endpointFloorProfile.reserve(passage.controlPoints.size());
             for(const auto& point:passage.controlPoints)
             {
-                chamberFloorControls.push_back({
+                endpointFloorControls.push_back({
                     static_cast<double>(point.positionSubvoxels[0]),
                     static_cast<double>(point.positionSubvoxels[1]),
                     static_cast<double>(point.positionSubvoxels[2]),
                     static_cast<double>(point.radiusSubvoxels)});
-                chamberFloorProfile.push_back(static_cast<double>(
+                endpointFloorProfile.push_back(static_cast<double>(
                     point.positionSubvoxels[2]-point.radiusSubvoxels));
             }
             const auto routePoints=[&](const ResolvedLayoutStratumV2& host)
@@ -6039,12 +5884,12 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
                     route.erase(route.begin(),route.end()-2);
                 double routeHeight=0.0,distanceSquared=0.0;
                 if(VoxelForgeCore::PassageSpline::ClosestRouteHeightAtXY(route,
-                        chamberFloorControls.front()[0],chamberFloorControls.front()[1],
+                        endpointFloorControls.front()[0],endpointFloorControls.front()[1],
                         routeHeight,distanceSquared)
-                    &&distanceSquared<=std::pow(chamberFloorControls.front()[3]
+                    &&distanceSquared<=std::pow(endpointFloorControls.front()[3]
                         +2.0*qPerMetre,2.0))
                     VoxelForgeCore::PassageSpline::BlendEndpointFloorToRoute(
-                        chamberFloorControls,chamberFloorProfile,0,route,qPerMetre,
+                        endpointFloorControls,endpointFloorProfile,0,route,qPerMetre,
                         upper.generatorKind=="SurfaceWorld"?0.98:1.13);
             }
             if(lower.generatorKind=="TunnelNetwork"
@@ -6054,31 +5899,30 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
                 if(route.size()>2)route.resize(2);
                 double routeHeight=0.0,distanceSquared=0.0;
                 if(VoxelForgeCore::PassageSpline::ClosestRouteHeightAtXY(route,
-                        chamberFloorControls[lowerMouthIndex][0],
-                        chamberFloorControls[lowerMouthIndex][1],
+                        endpointFloorControls[lowerMouthIndex][0],
+                        endpointFloorControls[lowerMouthIndex][1],
                         routeHeight,distanceSquared)
                     &&distanceSquared<=std::pow(
-                        chamberFloorControls[lowerMouthIndex][3]
+                        endpointFloorControls[lowerMouthIndex][3]
                             +2.0*qPerMetre,2.0))
                     VoxelForgeCore::PassageSpline::BlendEndpointFloorToRoute(
-                        chamberFloorControls,chamberFloorProfile,
+                        endpointFloorControls,endpointFloorProfile,
                         lowerMouthIndex,route,qPerMetre);
             }
-            const double upperEndRunFloor=chamberFloorProfile.front();
-            const double lowerEndRunFloor=chamberFloorProfile[lowerMouthIndex];
-            for(std::size_t i=0;i<chamberFloorProfile.size();++i)
+            const double upperEndRunFloor=endpointFloorProfile.front();
+            const double lowerEndRunFloor=endpointFloorProfile[lowerMouthIndex];
+            for(std::size_t i=0;i<endpointFloorProfile.size();++i)
             {
                 if(cumulative[i]<=upperFlatEndDistance)
-                    chamberFloorProfile[i]=upperEndRunFloor;
+                    endpointFloorProfile[i]=upperEndRunFloor;
                 else if(cumulative[i]>=lowerFlatStartDistance)
-                    chamberFloorProfile[i]=lowerEndRunFloor;
+                    endpointFloorProfile[i]=lowerEndRunFloor;
             }
-            // Commit the endpoint route fit into h(s) before chamber records are
-            // resolved. The passage field and both landing planes then consume the
-            // same deterministic profile instead of blending the chamber in later.
+            // Store route binding and level end runs in h(s), then use that profile
+            // directly for the bore and its landing-pad stamp.
             for(std::size_t i=0;i<passage.controlPoints.size();++i)
                 passage.controlPoints[i].positionSubvoxels[2]=static_cast<std::int64_t>(
-                    std::llround(chamberFloorProfile[i]))
+                    std::llround(endpointFloorProfile[i]))
                     +passage.controlPoints[i].radiusSubvoxels;
             const auto endRunAudit=AuditResolvedLayoutPassageEndRunsV1(
                 passage,layout.coreVoxelSizeMicrometres,endRunLength);
@@ -6090,117 +5934,6 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
                 endRunAudit.startMaximumGradeDegrees,
                 endRunAudit.endMaximumGradeDegrees,
                 endRunAudit.passed?"PASS":"FAIL");
-            const auto resolveLandingChamber=[&](
-                ResolvedLayoutPassageLandingChamberV1& chamber,
-                const std::array<std::int64_t,3>& mouth,std::size_t endpointIndex,
-                std::size_t neighborIndex,const ResolvedLayoutStratumV2& host,
-                const char* side)
-            {
-                chamber.floorCenterSubvoxels=mouth;
-                chamber.radiusSubvoxels=mouthRadius+3*qPerMetre;
-                chamber.clearHeightSubvoxels=static_cast<std::int64_t>(
-                    std::llround(4.5*qPerMetre));
-                const auto& endpoint=passage.controlPoints[endpointIndex];
-                const auto& neighbor=passage.controlPoints[neighborIndex];
-                const std::int64_t endpointFloor=static_cast<std::int64_t>(
-                    std::llround(chamberFloorProfile[endpointIndex]));
-                const std::int64_t neighborFloor=static_cast<std::int64_t>(
-                    std::llround(chamberFloorProfile[neighborIndex]));
-                chamber.floorCenterSubvoxels[2]=endpointFloor;
-                const std::int64_t dx=endpoint.positionSubvoxels[0]
-                    -neighbor.positionSubvoxels[0];
-                const std::int64_t dy=endpoint.positionSubvoxels[1]
-                    -neighbor.positionSubvoxels[1];
-                const std::int64_t dz=endpointFloor-neighborFloor;
-                const std::int64_t horizontalSquared=dx*dx+dy*dy;
-                if(horizontalSquared<=0)
-                {error=passage.stableId+" "+side+" landing chamber has no endpoint tangent";return false;}
-                chamber.floorGradientQ16={
-                    PassageRoundRatio(dx<0?-dz:dz,std::abs(dx)*65536,
-                        horizontalSquared),
-                    PassageRoundRatio(dy<0?-dz:dz,std::abs(dy)*65536,
-                        horizontalSquared)};
-                if(host.generatorKind=="SurfaceWorld"&&side[0]=='u')
-                {
-                    // The surface route enters the outer half of this chamber. Fit
-                    // its landing plane to that receiving route, while keeping its
-                    // center height equal to the passage's planned h(s) endpoint.
-                    const auto surfaceRoute=routePoints(host);
-                    const double radiusSquared=static_cast<double>(
-                        chamber.radiusSubvoxels)*chamber.radiusSubvoxels;
-                    double farthestDistanceSquared=0.0;
-                    std::array<double,3> farthestPoint{};
-                    for(const auto& routePoint:surfaceRoute)
-                    {
-                        const double routeDx=routePoint[0]-mouth[0];
-                        const double routeDy=routePoint[1]-mouth[1];
-                        const double distanceSquared=routeDx*routeDx+routeDy*routeDy;
-                        if(distanceSquared<=radiusSquared
-                            &&distanceSquared>farthestDistanceSquared)
-                        {
-                            farthestDistanceSquared=distanceSquared;
-                            farthestPoint=routePoint;
-                        }
-                    }
-                    double mouthRouteHeight=0.0,mouthRouteDistanceSquared=0.0;
-                    if(farthestDistanceSquared>0.0
-                        &&VoxelForgeCore::PassageSpline::ClosestRouteHeightAtXY(
-                            surfaceRoute,static_cast<double>(mouth[0]),
-                            static_cast<double>(mouth[1]),mouthRouteHeight,
-                            mouthRouteDistanceSquared))
-                    {
-                        const std::int64_t surfaceDx=static_cast<std::int64_t>(
-                            std::llround(farthestPoint[0]-mouth[0]));
-                        const std::int64_t surfaceDy=static_cast<std::int64_t>(
-                            std::llround(farthestPoint[1]-mouth[1]));
-                        const std::int64_t surfaceDz=static_cast<std::int64_t>(
-                            std::llround(farthestPoint[2]-mouthRouteHeight));
-                        const std::int64_t surfaceHorizontalSquared=surfaceDx*surfaceDx
-                            +surfaceDy*surfaceDy;
-                        if(surfaceHorizontalSquared>0)
-                            chamber.floorGradientQ16={
-                                PassageRoundRatio(surfaceDx<0?-surfaceDz:surfaceDz,
-                                    std::abs(surfaceDx)*65536,
-                                    surfaceHorizontalSquared),
-                                PassageRoundRatio(surfaceDy<0?-surfaceDz:surfaceDz,
-                                    std::abs(surfaceDy)*65536,
-                                    surfaceHorizontalSquared)};
-                    }
-                }
-                const std::uint64_t gradientSquared=static_cast<std::uint64_t>(
-                    chamber.floorGradientQ16[0]*chamber.floorGradientQ16[0]
-                    +chamber.floorGradientQ16[1]*chamber.floorGradientQ16[1]);
-                const std::int64_t gradientMagnitude=static_cast<std::int64_t>(
-                    PassageIsqrt(gradientSquared));
-                constexpr std::int64_t MaximumLandingGradeQ16=17560;
-                if(gradientMagnitude>MaximumLandingGradeQ16)
-                {error=passage.stableId+" "+side+" landing chamber floor exceeds 15 degrees";return false;}
-                const std::int64_t planeReachQ=PassageRoundRatio(
-                    chamber.radiusSubvoxels,gradientMagnitude,65536);
-                const std::int64_t shellQ=static_cast<std::int64_t>(
-                    std::llround(0.75*qPerMetre));
-                const auto qToUm=[&](std::int64_t q)
-                {return q*static_cast<std::int64_t>(layout.coreVoxelSizeMicrometres)
-                    /WorldAssemblySubvoxelsPerVoxel;};
-                if(!host.content.presentInCurrentField
-                    ||qToUm(chamber.floorCenterSubvoxels[2]-planeReachQ-shellQ)
-                        <host.content.bottomMicrometres
-                    ||qToUm(chamber.floorCenterSubvoxels[2]+planeReachQ
-                        +chamber.clearHeightSubvoxels+shellQ)
-                        >host.content.topMicrometres)
-                {
-                    error=passage.stableId+" "+side
-                        +" landing chamber does not fit inside its host content band";
-                    return false;
-                }
-                return true;
-            };
-            if(!resolveLandingChamber(passage.upperLandingChamber,upperMouth,0,1,
-                    upper,"upper")
-                ||!resolveLandingChamber(passage.lowerLandingChamber,lowerMouth,
-                    lowerMouthIndex,lowerMouthIndex-1,lower,"lower"))
-                return false;
-            passage.floorProfileIncludesLandingChambers=true;
             const auto overlapCensus=AuditResolvedLayoutPassageSelfOverlapV1(
                 passage,layout.coreVoxelSizeMicrometres);
             std::printf("[PassageTubeSelfOverlapCensus] id=%s segment_pairs=%llu measured_pairs=%llu local_exempt_pairs=%llu overlap_pairs=%llu first_overlap_segments=(%llu,%llu) end_turn_max_deg=%.3f end_turn_violations=%u landing_column_violations=%llu minimum_clearance_m=%.6f status=%s\n",
@@ -6256,14 +5989,20 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
                         endRunLength/static_cast<double>(qPerMetre));
                 }
             }
-            std::printf("[PassageLandingChamberPlan] id=%s upper_radius_m=%.3f lower_radius_m=%.3f clear_height_m=4.500 upper_floor_grade_q16=(%lld,%lld) lower_floor_grade_q16=(%lld,%lld) status=PASS\n",
+            std::printf("[PassageLandingPadPlan] id=%s upper_radius_m=%.3f lower_radius_m=%.3f upper_floor_z_m=%.3f lower_floor_z_m=%.3f source=h(s) status=PASS\n",
                 passage.stableId.c_str(),
-                passage.upperLandingChamber.radiusSubvoxels/static_cast<double>(qPerMetre),
-                passage.lowerLandingChamber.radiusSubvoxels/static_cast<double>(qPerMetre),
-                static_cast<long long>(passage.upperLandingChamber.floorGradientQ16[0]),
-                static_cast<long long>(passage.upperLandingChamber.floorGradientQ16[1]),
-                static_cast<long long>(passage.lowerLandingChamber.floorGradientQ16[0]),
-                static_cast<long long>(passage.lowerLandingChamber.floorGradientQ16[1]));
+                ResolvedLayoutPassageLandingDiscRadiusSubvoxels(
+                    passage.mouthRadiusSubvoxels,layout.coreVoxelSizeMicrometres)
+                    /static_cast<double>(qPerMetre),
+                ResolvedLayoutPassageLandingDiscRadiusSubvoxels(
+                    passage.mouthRadiusSubvoxels,layout.coreVoxelSizeMicrometres)
+                    /static_cast<double>(qPerMetre),
+                (passage.controlPoints.front().positionSubvoxels[2]
+                    -passage.controlPoints.front().radiusSubvoxels)
+                    /static_cast<double>(qPerMetre),
+                (passage.controlPoints[passage.lowerMouthControlIndex].positionSubvoxels[2]
+                    -passage.controlPoints[passage.lowerMouthControlIndex].radiusSubvoxels)
+                    /static_cast<double>(qPerMetre));
             layout.passages.push_back(std::move(passage));
         }
     }