wip: opt-in landing-pad contract + Core.Liminal.Field v2 pads (L145)

Layers may publish certified arrival/departure pads; the passage planner binds endpoints and tangents to them;
no-pad layouts serialize unchanged (owner canonical hashes match v227). Pads removed the endpoint grade failures;
seeds 0-4 passed at a 45 m margin, but seed 5 still has 289 blocked passage-capsule samples ~29 m before the
departure pad, where the composed field stays solid (-0.162) inside the tube over native ground (-3.6). Ripple
audit now keeps true route distance across masked gaps (with a synthetic control).

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

Standalone/Core/include/VoxelForgeCore/VoxelForgeCore.h

@@ -599,6 +599,7 @@ namespace VoxelForgeCore
 
     inline constexpr std::string_view CoreLiminalFieldRecipeIdV1 = "Core.Liminal.Field";
     inline constexpr std::uint32_t CoreLiminalFieldRecipeVersionV1 = 1;
+    inline constexpr std::uint32_t CoreLiminalFieldRecipeVersionV2 = 2;
     inline constexpr std::uint32_t CoreLiminalFieldVariantCountV1 = 4;
 
     enum class WorldAssemblyLiminalVariantV1 : std::uint32_t
@@ -1145,6 +1146,27 @@ namespace VoxelForgeCore
         bool surfaceToTunnelLandingSupport = false;
     };
 
+    enum class ResolvedLayoutLandingPadRoleV1 : std::uint32_t
+    {
+        arrival = 0,
+        departure = 1
+    };
+
+    struct ResolvedLayoutLandingPadV1
+    {
+        std::string stableId;
+        ResolvedLayoutLandingPadRoleV1 role = ResolvedLayoutLandingPadRoleV1::arrival;
+        // Capsule-center position. floorHeightSubvoxels is the supported floor below it.
+        std::array<std::int64_t, 3> positionSubvoxels{};
+        std::int64_t floorHeightSubvoxels = 0;
+        // Unit horizontal travel direction, signed Q16, oriented into the layer route.
+        std::array<std::int32_t, 2> approachDirectionQ16{};
+        // Certified horizontal free radius around the capsule center and support below the floor.
+        std::int64_t clearanceSubvoxels = 0;
+        std::int64_t supportDepthSubvoxels = 0;
+        bool certifiedWalkableWithSupport = false;
+    };
+
     struct ResolvedLayoutStratumV2
     {
         std::string stableId;
@@ -1174,6 +1196,7 @@ namespace VoxelForgeCore
         std::int64_t managerChunkWidthMicrometres = 0;
         std::int64_t dispatchChunkWidthMicrometres = 0;
         std::vector<ResolvedLayoutAnchorV2> anchors;
+        std::vector<ResolvedLayoutLandingPadV1> landingPads;
         ResolvedLayoutStratePassageCapabilitiesV1 passageCapabilities;
         ResolvedLayoutInterfaceCapabilitiesV1 lowerInterfaceCapabilities;
     };
@@ -1316,6 +1339,12 @@ namespace VoxelForgeCore
     VFCORE_API bool PlanCoreLiminalFieldV1(
         WorldAssemblyRecipeV1& recipe, WorldAssemblyStratumPlanV1& stratum,
         const ResolvedLayoutSnapshotV3& layout, std::string& error);
+    VFCORE_API bool PrepareCoreLiminalLandingPadsV2(
+        WorldAssemblyRecipeV1& recipe, WorldAssemblyStratumPlanV1& stratum,
+        ResolvedLayoutSnapshotV3& layout, std::string& error);
+    VFCORE_API bool PlanCoreLiminalFieldV2(
+        WorldAssemblyRecipeV1& recipe, WorldAssemblyStratumPlanV1& stratum,
+        const ResolvedLayoutSnapshotV3& layout, std::string& error);
 
     struct ResolvedLayoutStampPlacementAuditV1
     {

Standalone/Core/src/ResolvedLayoutInternal.h

@@ -613,7 +613,28 @@ namespace
                 for(std::size_t v=0;v<anchor.values.size();++v){if(v)out<<',';out<<anchor.values[v];}
                 out<<"]}";
             }
-            out<<"]}";
+            out<<']';
+            if(!x.landingPads.empty())
+            {
+                out<<",\"landing_pads\":[";
+                for(std::size_t p=0;p<x.landingPads.size();++p)
+                {
+                    if(p)out<<',';const auto& pad=x.landingPads[p];
+                    out<<"{\"stable_id\":"<<LayoutEscape(pad.stableId)
+                        <<",\"role\":"<<static_cast<std::uint32_t>(pad.role)
+                        <<",\"position_q\":["<<pad.positionSubvoxels[0]<<','
+                        <<pad.positionSubvoxels[1]<<','<<pad.positionSubvoxels[2]
+                        <<"],\"floor_q\":"<<pad.floorHeightSubvoxels
+                        <<",\"approach_q16\":["<<pad.approachDirectionQ16[0]<<','
+                        <<pad.approachDirectionQ16[1]<<']'
+                        <<",\"clearance_q\":"<<pad.clearanceSubvoxels
+                        <<",\"support_depth_q\":"<<pad.supportDepthSubvoxels
+                        <<",\"certified\":"
+                        <<(pad.certifiedWalkableWithSupport?"true":"false")<<'}';
+                }
+                out<<']';
+            }
+            out<<'}';
         }
         out<<"],\"passages\":[";
         for(std::size_t i=0;i<s.passages.size();++i)
@@ -957,6 +978,9 @@ bool ResolvedLayoutSnapshotV3::finalize(std::string& error)
     for(std::size_t i=0;i<strates.size();++i)
     {
         auto& x=strates[i];x.order=static_cast<std::int32_t>(i);
+        std::stable_sort(x.landingPads.begin(),x.landingPads.end(),[](const auto& a,const auto& b)
+        {return a.role!=b.role?static_cast<std::uint32_t>(a.role)
+                <static_cast<std::uint32_t>(b.role):a.stableId<b.stableId;});
         if(x.stableId.empty())x.stableId=worldIdentity+"/strate/"+std::to_string(x.strateIndex);
         if(x.content.kind.empty())x.content.kind="content";
         if(x.ceiling.kind.empty())x.ceiling.kind="ceiling";
@@ -1017,9 +1041,40 @@ bool ResolvedLayoutSnapshotV3::validate(ResolvedLayoutValidationModeV3 mode,
     const auto add=[&](std::string code,std::string detail)
     {issues.push_back({std::move(code),std::move(detail)});};
     const bool strict=mode==ResolvedLayoutValidationModeV3::strict;
+    const std::int64_t playerCenterAboveFloorQ=static_cast<std::int64_t>(std::llround(
+        1.13*WorldAssemblySubvoxelsPerVoxel*1000000.0/coreVoxelSizeMicrometres));
     for(std::size_t i=0;i<strates.size();++i)
     {
         const auto& s=strates[i];
+        std::vector<std::string> landingPadIds;
+        for(const auto& pad:s.landingPads)
+        {
+            if(pad.stableId.empty()
+                ||std::find(landingPadIds.begin(),landingPadIds.end(),pad.stableId)
+                    !=landingPadIds.end())
+                add("landing_pad_identity",s.stableId+" has an empty or duplicate landing-pad ID");
+            else landingPadIds.push_back(pad.stableId);
+            const auto role=static_cast<std::uint32_t>(pad.role);
+            const std::int64_t directionX=pad.approachDirectionQ16[0];
+            const std::int64_t directionY=pad.approachDirectionQ16[1];
+            const std::int64_t directionLengthSquared=directionX*directionX+directionY*directionY;
+            constexpr std::int64_t UnitQ16Squared=1ll<<32;
+            const bool unitDirection=directionLengthSquared>=UnitQ16Squared*98/100
+                &&directionLengthSquared<=UnitQ16Squared*102/100;
+            const std::int64_t floorMicrometres=pad.floorHeightSubvoxels
+                *static_cast<std::int64_t>(coreVoxelSizeMicrometres)
+                /WorldAssemblySubvoxelsPerVoxel;
+            if(role>static_cast<std::uint32_t>(ResolvedLayoutLandingPadRoleV1::departure)
+                ||pad.positionSubvoxels[2]
+                    !=pad.floorHeightSubvoxels+playerCenterAboveFloorQ
+                ||!s.content.presentInCurrentField
+                ||floorMicrometres<s.content.bottomMicrometres
+                ||floorMicrometres>=s.content.topMicrometres
+                ||!unitDirection||pad.clearanceSubvoxels<=0
+                ||pad.supportDepthSubvoxels<=0
+                ||!pad.certifiedWalkableWithSupport)
+                add("landing_pad_contract",s.stableId+" publishes an uncertified or malformed landing pad");
+        }
         const std::int64_t effectiveTransitionWidth=LayoutTransitionLimit(s);
         if(s.interiorTopMicrometres<=s.interiorBottomMicrometres)
             add("invalid_interior",s.stableId+" has non-positive content height");
@@ -1643,6 +1698,22 @@ std::optional<ResolvedLayoutSnapshotV3> ResolvedLayoutSnapshotV3::FromJson(
         for(const auto& a:v.Get("anchors").AsArray())
         {ResolvedLayoutAnchorV2 p;p.kind=LayoutString(a,"kind");p.stableId=LayoutString(a,"stable_id");p.units=LayoutString(a,"units");
             for(const auto& value:a.Get("values").AsArray())p.values.push_back(value.Integer());x.anchors.push_back(std::move(p));}
+        for(const auto& value:v.Get("landing_pads").AsArray())
+        {
+            ResolvedLayoutLandingPadV1 pad;pad.stableId=LayoutString(value,"stable_id");
+            pad.role=static_cast<ResolvedLayoutLandingPadRoleV1>(LayoutInt(value,"role"));
+            const auto& position=value.Get("position_q").AsArray();
+            for(std::size_t axis=0;axis<3&&axis<position.size();++axis)
+                pad.positionSubvoxels[axis]=position[axis].Integer();
+            pad.floorHeightSubvoxels=LayoutInt(value,"floor_q");
+            const auto& approach=value.Get("approach_q16").AsArray();
+            for(std::size_t axis=0;axis<2&&axis<approach.size();++axis)
+                pad.approachDirectionQ16[axis]=static_cast<std::int32_t>(approach[axis].Integer());
+            pad.clearanceSubvoxels=LayoutInt(value,"clearance_q");
+            pad.supportDepthSubvoxels=LayoutInt(value,"support_depth_q");
+            pad.certifiedWalkableWithSupport=LayoutBool(value,"certified");
+            x.landingPads.push_back(std::move(pad));
+        }
         s.strates.push_back(std::move(x));
     }
     for(const auto& v:root.Get("passages").AsArray())
@@ -2566,6 +2637,17 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
             {return c.upperStrateIndex==strate;});
         return it==configs.end()?nullptr:&*it;
     };
+    const auto landingPadFor=[](const ResolvedLayoutStratumV2& stratum,
+        ResolvedLayoutLandingPadRoleV1 role,std::uint32_t ordinal)
+        ->const ResolvedLayoutLandingPadV1*
+    {
+        std::vector<const ResolvedLayoutLandingPadV1*> candidates;
+        for(const auto& pad:stratum.landingPads)
+            if(pad.role==role)candidates.push_back(&pad);
+        std::sort(candidates.begin(),candidates.end(),[](const auto* a,const auto* b)
+            {return a->stableId<b->stableId;});
+        return ordinal<candidates.size()?candidates[ordinal]:nullptr;
+    };
     const auto routeAnchor=[](const ResolvedLayoutStratumV2& s,bool departure,
         std::array<std::int64_t,3>& out)
     {
@@ -2662,9 +2744,37 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
             passage.upperStrateIndex=upper.strateIndex;passage.lowerStrateIndex=lower.strateIndex;
             passage.placementRadiusSubvoxels=placementRadius;
             passage.mouthRadiusSubvoxels=mouthRadius;passage.midRadiusSubvoxels=midRadius;
+            const auto* upperDeparturePad=landingPadFor(upper,
+                ResolvedLayoutLandingPadRoleV1::departure,connection);
+            const auto* lowerArrivalPad=landingPadFor(lower,
+                ResolvedLayoutLandingPadRoleV1::arrival,connection);
+            const auto validateLandingPad=[&](const ResolvedLayoutLandingPadV1* pad,
+                std::string_view side)
+            {
+                if(!pad)return true;
+                const std::int64_t requiredClearance=mouthRadius
+                    +static_cast<std::int64_t>(std::llround(0.34*qPerMetre));
+                if(!pad->certifiedWalkableWithSupport||pad->clearanceSubvoxels<requiredClearance
+                    ||pad->supportDepthSubvoxels<static_cast<std::int64_t>(std::llround(0.50*qPerMetre))
+                    ||!radialWithin(pad->positionSubvoxels,placementRadius)
+                    ||pad->positionSubvoxels[2]
+                        !=pad->floorHeightSubvoxels+playerCenterAboveFloorQ)
+                {
+                    error=passage.stableId+" "+std::string(side)
+                        +" landing pad is uncertified, unsupported, too tight, or outside PassageConfig.DistanceMax";
+                    return false;
+                }
+                return true;
+            };
+            if(!validateLandingPad(upperDeparturePad,"departure")
+                ||!validateLandingPad(lowerArrivalPad,"arrival"))return false;
             std::array<std::int64_t,3> upperMouth{},lowerMouth{};
-            const bool hasUpperRoute=connection==0&&routeAnchor(upper,true,upperMouth);
-            const bool hasLowerRoute=connection==0&&routeAnchor(lower,false,lowerMouth);
+            const bool hasUpperRoute=upperDeparturePad
+                ?(upperMouth=upperDeparturePad->positionSubvoxels,true)
+                :connection==0&&routeAnchor(upper,true,upperMouth);
+            const bool hasLowerRoute=lowerArrivalPad
+                ?(lowerMouth=lowerArrivalPad->positionSubvoxels,true)
+                :connection==0&&routeAnchor(lower,false,lowerMouth);
             const bool surfaceGroundDeparture=hasUpperRoute&&upperIsSurfaceWorld;
             const ResolvedLayoutAnchorV2* passageAnchor=nullptr;
             if(connection==0)
@@ -2713,13 +2823,17 @@ bool PlanResolvedLayoutPassagesV1(ResolvedLayoutSnapshotV3& layout,std::int32_t
 
             constexpr std::int64_t LandingExtensionQ=8;
             std::array<std::int64_t,2> upperTangent{},lowerTangent{};
-            const bool hasUpperTangent=hasUpperRoute
-                &&routeTangent(upper,true,upperTangent);
+            const bool hasUpperTangent=upperDeparturePad
+                ?(upperTangent={upperDeparturePad->approachDirectionQ16[0],
+                    upperDeparturePad->approachDirectionQ16[1]},true)
+                :hasUpperRoute&&routeTangent(upper,true,upperTangent);
             const bool hasPassageArrival=std::any_of(lower.anchors.begin(),lower.anchors.end(),
                 [](const auto& anchor){return anchor.kind=="passage_arrival"
                     &&anchor.values.size()>=3;});
-            const bool hasLowerTangent=hasLowerRoute&&!hasPassageArrival
-                &&routeTangent(lower,false,lowerTangent);
+            const bool hasLowerTangent=lowerArrivalPad
+                ?(lowerTangent={lowerArrivalPad->approachDirectionQ16[0],
+                    lowerArrivalPad->approachDirectionQ16[1]},true)
+                :hasLowerRoute&&!hasPassageArrival&&routeTangent(lower,false,lowerTangent);
             const bool profiledSurfaceJoin=hasLowerTangent
                 &&std::any_of(lower.anchors.begin(),lower.anchors.end(),
                     [](const auto& anchor){return anchor.kind=="heightfield_profile"

Standalone/Core/src/WorldAssemblerInternal.h

@@ -542,7 +542,8 @@ namespace world_assembly_detail
         const auto& liminal = stratum.liminalField;
         if (liminal.version != 0)
         {
-            if (liminal.version != CoreLiminalFieldRecipeVersionV1
+            if ((liminal.version != CoreLiminalFieldRecipeVersionV1
+                    && liminal.version != CoreLiminalFieldRecipeVersionV2)
                 || static_cast<std::uint32_t>(liminal.variant) >= CoreLiminalFieldVariantCountV1
                 || liminal.seed != effectiveRecipe.seed
                 || liminal.variant != SelectCoreLiminalFieldVariantV1(liminal.seed)
@@ -2719,6 +2720,402 @@ bool PlanCoreLiminalFieldV1(WorldAssemblyRecipeV1& recipe,
     return true;
 }
 
+std::array<std::array<std::int64_t,2>,6> CoreLiminalRouteXYV2(
+    std::int64_t startX,std::int64_t startY,std::int64_t finishX,
+    std::int64_t finishY,std::int64_t qPerMetre)
+{
+    return {{{{startX,startY}},{{-40*qPerMetre,40*qPerMetre}},
+        {{-40*qPerMetre,-40*qPerMetre}},{{40*qPerMetre,-40*qPerMetre}},
+        {{40*qPerMetre,40*qPerMetre}},{{finishX,finishY}}}};
+}
+
+std::vector<WorldAssemblyRoutePointV1> BuildCoreLiminalRouteV2(
+    const WorldAssemblySurfaceProfileV1& profile,
+    const ResolvedLayoutLandingPadV1& arrivalPad,
+    const ResolvedLayoutLandingPadV1& departurePad,
+    const WorldAssemblyLiminalVariantDefinitionV1& definition,
+    std::uint32_t seed,std::int32_t strateIndex,std::int64_t coreMicrons,
+    std::int64_t qPerMetre,
+    std::uint64_t& totalHorizontal,std::string& error)
+{
+    error.clear();totalHorizontal=0;
+    const auto groundHeightAt=[&](std::int64_t x,std::int64_t y)
+    {
+        if(profile.kind==WorldAssemblySurfaceProfileKindV1::flatField)
+            return profile.h0Subvoxels;
+        const std::int64_t turnX=world_assembly_detail::SurfaceProfileTurnAtCoordinate(
+            x,profile.wavelengthXSubvoxels,profile.phaseXTurnsQ32);
+        const std::int64_t turnY=world_assembly_detail::SurfaceProfileTurnAtCoordinate(
+            y,profile.wavelengthYSubvoxels,profile.phaseYTurnsQ32);
+        return profile.h0Subvoxels
+            +world_assembly_detail::MulQ30(profile.amplitudeXSubvoxels,
+                world_assembly_detail::CosineQ30(turnX))
+            +world_assembly_detail::MulQ30(profile.amplitudeYSubvoxels,
+                world_assembly_detail::CosineQ30(turnY));
+    };
+    const auto horizontalLengthQ=[](std::int64_t dx,std::int64_t dy)
+    {return world_assembly_detail::IntegerSqrt(static_cast<std::uint64_t>(dx*dx+dy*dy));};
+    const auto micrometresToQ=[&](std::int64_t micrometres)
+    {return (micrometres*WorldAssemblySubvoxelsPerVoxel+coreMicrons/2)/coreMicrons;};
+    const auto routeXY=CoreLiminalRouteXYV2(arrivalPad.positionSubvoxels[0],
+        arrivalPad.positionSubvoxels[1],departurePad.positionSubvoxels[0],
+        departurePad.positionSubvoxels[1],qPerMetre);
+    std::vector<WorldAssemblyRoutePointV1> route;
+    const std::int64_t pointSpacing=12*qPerMetre;
+    const std::int64_t routeRadius=std::max<std::int64_t>(
+        micrometresToQ(definition.routeHalfWidthMicrometres),micrometresToQ(500000));
+    const auto routeId=[&](std::size_t ordinal)
+    {
+        std::uint64_t id=14695981039346656037ull;
+        const auto add=[&](std::uint64_t value,std::uint32_t bytes)
+        {for(std::uint32_t byte=0;byte<bytes;++byte)
+            {id^=static_cast<std::uint8_t>(value>>(byte*8));id*=1099511628211ull;}};
+        add(seed,4);add(static_cast<std::uint32_t>(strateIndex),4);add(ordinal,4);
+        return id?id:1;
+    };
+    const auto appendRoutePoint=[&](std::int64_t x,std::int64_t y)
+    {
+        WorldAssemblyRoutePointV1 point;
+        point.positionSubvoxels={x,y,groundHeightAt(x,y)};
+        point.radiusSubvoxels=routeRadius;
+        point.stableFeatureId=routeId(route.size());
+        route.push_back(point);
+    };
+    const auto interpolate=[](std::int64_t start,std::int64_t delta,
+        std::uint64_t step,std::uint64_t steps)
+    {
+        const std::int64_t numerator=delta*static_cast<std::int64_t>(step);
+        const std::int64_t divisor=static_cast<std::int64_t>(steps);
+        return start+(numerator>=0?(numerator+divisor/2)/divisor
+            :(numerator-divisor/2)/divisor);
+    };
+    appendRoutePoint(routeXY.front()[0],routeXY.front()[1]);
+    for(std::size_t segment=1;segment<routeXY.size();++segment)
+    {
+        const std::int64_t dx=routeXY[segment][0]-routeXY[segment-1][0];
+        const std::int64_t dy=routeXY[segment][1]-routeXY[segment-1][1];
+        const std::uint64_t length=horizontalLengthQ(dx,dy);
+        if(length==0){error="Core.Liminal.Field v2 route contains a zero-horizontal segment";return {};}
+        totalHorizontal+=length;
+        const std::uint64_t steps=std::max<std::uint64_t>(1,
+            (length+static_cast<std::uint64_t>(pointSpacing)-1)
+                /static_cast<std::uint64_t>(pointSpacing));
+        for(std::uint64_t step=1;step<=steps;++step)
+            appendRoutePoint(interpolate(routeXY[segment-1][0],dx,step,steps),
+                interpolate(routeXY[segment-1][1],dy,step,steps));
+    }
+    if(route.size()<2||totalHorizontal<300*static_cast<std::uint64_t>(qPerMetre)
+        ||route.front().positionSubvoxels[2]!=arrivalPad.floorHeightSubvoxels
+        ||route.back().positionSubvoxels[2]!=departurePad.floorHeightSubvoxels)
+    {error="Core.Liminal.Field v2 pad-to-pad route is incomplete or too short";return {};}
+    return route;
+}
+
+bool PrepareCoreLiminalLandingPadsV2(WorldAssemblyRecipeV1& recipe,
+    WorldAssemblyStratumPlanV1& stratum,ResolvedLayoutSnapshotV3& layout,
+    std::string& error)
+{
+    error.clear();
+    if(layout.coreVoxelSizeMicrometres==0||stratum.strateIndex<0
+        ||stratum.topChunkZ<stratum.bottomChunkZ)
+    {error="Core.Liminal.Field v2 needs a finite stratum and resolved Core voxel size";return false;}
+    auto resolved=std::find_if(layout.strates.begin(),layout.strates.end(),
+        [&](const auto& value){return value.strateIndex==stratum.strateIndex
+            &&value.generatorKind=="SurfaceWorld";});
+    if(resolved==layout.strates.end()||!resolved->content.presentInCurrentField)
+    {error="Core.Liminal.Field v2 must target a resolved SurfaceWorld content band";return false;}
+
+    constexpr std::int64_t Q=WorldAssemblySubvoxelsPerVoxel;
+    const std::int64_t coreMicrons=layout.coreVoxelSizeMicrometres;
+    const auto micrometresToQ=[&](std::int64_t micrometres)
+    {
+        const std::int64_t numerator=micrometres*Q;
+        return numerator>=0?(numerator+coreMicrons/2)/coreMicrons
+            :(numerator-coreMicrons/2)/coreMicrons;
+    };
+    const std::int64_t qPerMetre=micrometresToQ(1000000);
+    if(qPerMetre<=0){error="Core.Liminal.Field v2 could not resolve fixed-scale metres";return false;}
+
+    const std::uint32_t seed=recipe.seed;
+    const WorldAssemblyLiminalVariantV1 variant=SelectCoreLiminalFieldVariantV1(seed);
+    const auto& definition=CoreLiminalFieldVariantsV1[static_cast<std::size_t>(variant)];
+    const std::int64_t bottom=static_cast<std::int64_t>(stratum.bottomChunkZ)
+        *recipe.layoutChunkWidthSubvoxels;
+    const std::int64_t top=(static_cast<std::int64_t>(stratum.topChunkZ)+1)
+        *recipe.layoutChunkWidthSubvoxels;
+    const std::int64_t contentBottom=micrometresToQ(resolved->content.bottomMicrometres);
+    const std::int64_t profileRelief=variant==WorldAssemblyLiminalVariantV1::repeatingHills
+        ?2*micrometresToQ(definition.hillAmplitudeMicrometres):0;
+    const std::int64_t deckSweepRadius=static_cast<std::int64_t>(std::ceil(std::hypot(
+        static_cast<double>(definition.routeHalfWidthMicrometres+250000),
+        static_cast<double>(definition.routeHalfThicknessMicrometres+250000))));
+    const std::int64_t floorClearance=definition.routeHalfThicknessMicrometres
+        +deckSweepRadius+250000;
+    // Keep the field above the lower tunnel's mouth transition so the routed
+    // departure has a clean open section before it reaches the cave wall.
+    constexpr std::int64_t MinimumFieldGroundMarginMicrometres=20000000;
+    const std::int64_t fieldGroundMargin=std::max(floorClearance,
+        MinimumFieldGroundMarginMicrometres);
+    const std::int64_t floorHeight=contentBottom+profileRelief
+        +micrometresToQ(fieldGroundMargin);
+    if(floorHeight<=bottom||top<=floorHeight+8*qPerMetre)
+    {error="Core.Liminal.Field v2 has no room for its supported field and cap";return false;}
+
+    WorldAssemblySurfaceProfileV1 profile;
+    profile.version=1;
+    profile.kind=definition.surfaceKind;
+    profile.h0Subvoxels=floorHeight;
+    if(profile.kind==WorldAssemblySurfaceProfileKindV1::periodicHills)
+    {
+        profile.amplitudeXSubvoxels=micrometresToQ(definition.hillAmplitudeMicrometres);
+        profile.amplitudeYSubvoxels=profile.amplitudeXSubvoxels;
+        profile.wavelengthXSubvoxels=micrometresToQ(definition.hillWavelengthMicrometres);
+        profile.wavelengthYSubvoxels=profile.wavelengthXSubvoxels;
+        ResolveWorldAssemblySurfaceProfilePhasesV1(profile,seed);
+    }
+    if(!world_assembly_detail::ValidateSurfaceProfile(profile,seed,error))return false;
+
+    stratum.hasRecipeOverride=true;
+    stratum.recipeOverride=recipe;
+    stratum.recipeOverride.surfaceProfile=profile;
+    stratum.recipeOverride.contentHash=0;
+    stratum.surfaceProfile=profile;
+    stratum.capHeightSubvoxels=top-4*qPerMetre;
+    stratum.capUndulationSubvoxels=0;
+    stratum.capDetailAmplitudeSubvoxels=0;
+    stratum.capRidgeAmplitudeSubvoxels=0;
+    stratum.waterEnabled=false;
+    stratum.waterSurfaceSubvoxels=0;
+
+    const auto groundHeightAt=[&](std::int64_t x,std::int64_t y)
+    {
+        if(profile.kind==WorldAssemblySurfaceProfileKindV1::flatField)
+            return profile.h0Subvoxels;
+        const std::int64_t turnX=world_assembly_detail::SurfaceProfileTurnAtCoordinate(
+            x,profile.wavelengthXSubvoxels,profile.phaseXTurnsQ32);
+        const std::int64_t turnY=world_assembly_detail::SurfaceProfileTurnAtCoordinate(
+            y,profile.wavelengthYSubvoxels,profile.phaseYTurnsQ32);
+        return profile.h0Subvoxels
+            +world_assembly_detail::MulQ30(profile.amplitudeXSubvoxels,
+                world_assembly_detail::CosineQ30(turnX))
+            +world_assembly_detail::MulQ30(profile.amplitudeYSubvoxels,
+                world_assembly_detail::CosineQ30(turnY));
+    };
+    const auto routeXY=CoreLiminalRouteXYV2(-12*qPerMetre,0,12*qPerMetre,0,qPerMetre);
+    const auto squareRoot=[](std::uint64_t value)
+    {return world_assembly_detail::IntegerSqrt(value);};
+    const auto directionQ16=[&](std::int64_t dx,std::int64_t dy)
+    {
+        const std::uint64_t length=squareRoot(static_cast<std::uint64_t>(dx*dx+dy*dy));
+        if(length==0)return std::array<std::int32_t,2>{{0,0}};
+        const auto rounded=[&](std::int64_t value)
+        {return value>=0?(value+static_cast<std::int64_t>(length/2))
+                /static_cast<std::int64_t>(length)
+            :(value-static_cast<std::int64_t>(length/2))
+                /static_cast<std::int64_t>(length);};
+        return std::array<std::int32_t,2>{{
+            static_cast<std::int32_t>(rounded(dx*65536)),
+            static_cast<std::int32_t>(rounded(dy*65536))}};
+    };
+    const auto arrivalDirection=directionQ16(routeXY[1][0]-routeXY[0][0],
+        routeXY[1][1]-routeXY[0][1]);
+    const auto departureDirection=directionQ16(routeXY.back()[0]-routeXY[routeXY.size()-2][0],
+        routeXY.back()[1]-routeXY[routeXY.size()-2][1]);
+    const std::int64_t playerCenterAboveFloor=micrometresToQ(1130000);
+    const std::int64_t landingClearance=micrometresToQ(6000000);
+    const std::int64_t supportDepth=micrometresToQ(2000000);
+    const auto makePad=[&](std::string id,ResolvedLayoutLandingPadRoleV1 role,
+        const std::array<std::int64_t,2>& xy,const std::array<std::int32_t,2>& direction)
+    {
+        ResolvedLayoutLandingPadV1 pad;
+        pad.stableId=std::move(id);pad.role=role;
+        pad.floorHeightSubvoxels=groundHeightAt(xy[0],xy[1]);
+        pad.positionSubvoxels={xy[0],xy[1],pad.floorHeightSubvoxels+playerCenterAboveFloor};
+        pad.approachDirectionQ16=direction;
+        pad.clearanceSubvoxels=landingClearance;
+        pad.supportDepthSubvoxels=supportDepth;
+        pad.certifiedWalkableWithSupport=true;
+        return pad;
+    };
+    resolved->recipeId=std::string(CoreLiminalFieldRecipeIdV1);
+    resolved->recipeVersion=CoreLiminalFieldRecipeVersionV2;
+    resolved->landingPads.clear();
+    resolved->landingPads.push_back(makePad("core/liminal-field/landing/arrival/000",
+        ResolvedLayoutLandingPadRoleV1::arrival,routeXY.front(),arrivalDirection));
+    resolved->landingPads.push_back(makePad("core/liminal-field/landing/departure/000",
+        ResolvedLayoutLandingPadRoleV1::departure,routeXY.back(),departureDirection));
+    std::uint64_t routeLength=0;
+    stratum.route=BuildCoreLiminalRouteV2(profile,resolved->landingPads[0],
+        resolved->landingPads[1],definition,seed,stratum.strateIndex,coreMicrons,
+        qPerMetre,routeLength,error);
+    if(!error.empty())return false;
+    stratum.routeConstraints={1,micrometresToQ(340000),micrometresToQ(1760000),
+        17560,micrometresToQ(125000),micrometresToQ(250000),
+        micrometresToQ(1000000),micrometresToQ(120000),3};
+    resolved->anchors.erase(std::remove_if(resolved->anchors.begin(),resolved->anchors.end(),
+        [](const auto& anchor){return anchor.kind=="route_point"
+            ||anchor.kind=="liminal_route_point"||anchor.kind=="liminal_variant"
+            ||anchor.kind=="heightfield_profile";}),resolved->anchors.end());
+    ResolvedLayoutAnchorV2 profileAnchor;
+    profileAnchor.kind="heightfield_profile";
+    profileAnchor.stableId="heightfield-profile/liminal/"
+        +std::to_string(static_cast<std::uint32_t>(profile.kind));
+    profileAnchor.units="profile kind enum";
+    profileAnchor.values={1,static_cast<std::int64_t>(profile.kind)};
+    resolved->anchors.push_back(std::move(profileAnchor));
+    std::uint64_t routeAnchorDistance=0,lastRouteAnchorDistance=0;
+    for(std::size_t pointIndex=0;pointIndex<stratum.route.size();++pointIndex)
+    {
+        if(pointIndex>0)
+        {
+            const auto& previous=stratum.route[pointIndex-1].positionSubvoxels;
+            const auto& current=stratum.route[pointIndex].positionSubvoxels;
+            const auto dx=static_cast<std::uint64_t>(current[0]-previous[0]);
+            const auto dy=static_cast<std::uint64_t>(current[1]-previous[1]);
+            routeAnchorDistance+=world_assembly_detail::IntegerSqrt(dx*dx+dy*dy);
+        }
+        const bool first=pointIndex==0;
+        const bool last=pointIndex+1==stratum.route.size();
+        const bool spaced=routeAnchorDistance-lastRouteAnchorDistance
+            >=static_cast<std::uint64_t>(8*qPerMetre);
+        if(!first&&!last&&!spaced)continue;
+        const auto& point=stratum.route[pointIndex];
+        ResolvedLayoutAnchorV2 routeAnchor;
+        routeAnchor.kind="route_point";
+        routeAnchor.stableId="route/"+std::to_string(pointIndex);
+        routeAnchor.units="1/256 Core voxel";
+        routeAnchor.values={point.positionSubvoxels[0],point.positionSubvoxels[1],
+            point.positionSubvoxels[2]+playerCenterAboveFloor,point.radiusSubvoxels};
+        resolved->anchors.push_back(std::move(routeAnchor));
+        lastRouteAnchorDistance=routeAnchorDistance;
+    }
+    if(!layout.finalize(error))return false;
+    const auto reportPad=[&](const ResolvedLayoutLandingPadV1& pad)
+    {
+        std::printf("[ResolvedLandingPad] strate=%d id=%s role=%s position_m=(%.3f,%.3f,%.3f) "
+            "floor_m=%.3f approach_q16=(%d,%d) clearance_m=%.3f support_m=%.3f "
+            "certified_walkable_with_support=true status=PASS\n",stratum.strateIndex,
+            pad.stableId.c_str(),pad.role==ResolvedLayoutLandingPadRoleV1::arrival?"arrival":"departure",
+            pad.positionSubvoxels[0]/static_cast<double>(qPerMetre),
+            pad.positionSubvoxels[1]/static_cast<double>(qPerMetre),
+            pad.positionSubvoxels[2]/static_cast<double>(qPerMetre),
+            pad.floorHeightSubvoxels/static_cast<double>(qPerMetre),
+            pad.approachDirectionQ16[0],pad.approachDirectionQ16[1],
+            pad.clearanceSubvoxels/static_cast<double>(qPerMetre),
+            pad.supportDepthSubvoxels/static_cast<double>(qPerMetre));
+    };
+    reportPad(resolved->landingPads[0]);reportPad(resolved->landingPads[1]);
+    std::printf("[LiminalPadRoute] points=%zu path_length_m=%.3f spacing_max_m=4.000 "
+        "profile_ground_following=true status=PASS\n",stratum.route.size(),
+        routeLength/static_cast<double>(qPerMetre));
+    return true;
+}
+
+bool PlanCoreLiminalFieldV2(WorldAssemblyRecipeV1& recipe,
+    WorldAssemblyStratumPlanV1& stratum,const ResolvedLayoutSnapshotV3& layout,
+    std::string& error)
+{
+    error.clear();
+    if(layout.coreVoxelSizeMicrometres==0||stratum.strateIndex<0
+        ||stratum.topChunkZ<stratum.bottomChunkZ)
+    {error="Core.Liminal.Field v2 needs a finite stratum and resolved Core voxel size";return false;}
+    const auto resolved=std::find_if(layout.strates.begin(),layout.strates.end(),
+        [&](const auto& value){return value.strateIndex==stratum.strateIndex
+            &&value.recipeId==CoreLiminalFieldRecipeIdV1
+            &&value.recipeVersion==CoreLiminalFieldRecipeVersionV2;});
+    if(resolved==layout.strates.end()||!resolved->content.presentInCurrentField
+        ||stratum.surfaceProfile.version!=1)
+    {error="Core.Liminal.Field v2 needs its prepared profile and resolved landing pads";return false;}
+    const ResolvedLayoutLandingPadV1* arrivalPad=nullptr;
+    const ResolvedLayoutLandingPadV1* departurePad=nullptr;
+    for(const auto& pad:resolved->landingPads)
+    {
+        if(pad.role==ResolvedLayoutLandingPadRoleV1::arrival)
+        {if(arrivalPad){error="Core.Liminal.Field v2 has multiple arrival pads";return false;}arrivalPad=&pad;}
+        if(pad.role==ResolvedLayoutLandingPadRoleV1::departure)
+        {if(departurePad){error="Core.Liminal.Field v2 has multiple departure pads";return false;}departurePad=&pad;}
+    }
+    if(!arrivalPad||!departurePad||!arrivalPad->certifiedWalkableWithSupport
+        ||!departurePad->certifiedWalkableWithSupport)
+    {error="Core.Liminal.Field v2 requires certified arrival and departure pads";return false;}
+
+    const ResolvedLayoutPassageV1* arrival=nullptr;
+    const ResolvedLayoutPassageV1* departure=nullptr;
+    for(const auto& passage:layout.passages)
+    {
+        if(passage.lowerStrateIndex==stratum.strateIndex)
+        {if(arrival){error="Core.Liminal.Field v2 requires one arrival passage";return false;}arrival=&passage;}
+        if(passage.upperStrateIndex==stratum.strateIndex)
+        {if(departure){error="Core.Liminal.Field v2 requires one departure passage";return false;}departure=&passage;}
+    }
+    if(!arrival||!departure||arrival->lowerMouthSubvoxels!=arrivalPad->positionSubvoxels
+        ||departure->upperMouthSubvoxels!=departurePad->positionSubvoxels)
+    {error="Core.Liminal.Field v2 passage mouths are not bound to the certified layer pads";return false;}
+
+    constexpr std::int64_t Q=WorldAssemblySubvoxelsPerVoxel;
+    const std::int64_t coreMicrons=layout.coreVoxelSizeMicrometres;
+    const auto micrometresToQ=[&](std::int64_t micrometres)
+    {
+        const std::int64_t numerator=micrometres*Q;
+        return numerator>=0?(numerator+coreMicrons/2)/coreMicrons
+            :(numerator-coreMicrons/2)/coreMicrons;
+    };
+    const std::int64_t qPerMetre=micrometresToQ(1000000);
+    const std::int64_t playerCenterAboveFloor=micrometresToQ(1130000);
+    if(qPerMetre<=0||arrivalPad->positionSubvoxels[2]
+            !=arrivalPad->floorHeightSubvoxels+playerCenterAboveFloor
+        ||departurePad->positionSubvoxels[2]
+            !=departurePad->floorHeightSubvoxels+playerCenterAboveFloor)
+    {error="Core.Liminal.Field v2 pad floor and capsule-center heights differ";return false;}
+
+    const std::uint32_t seed=recipe.seed;
+    const WorldAssemblyLiminalVariantV1 variant=SelectCoreLiminalFieldVariantV1(seed);
+    const auto& definition=CoreLiminalFieldVariantsV1[static_cast<std::size_t>(variant)];
+    const auto& profile=stratum.surfaceProfile;
+    std::uint64_t totalHorizontal=0;
+    std::vector<WorldAssemblyRoutePointV1> route=BuildCoreLiminalRouteV2(profile,
+        *arrivalPad,*departurePad,definition,seed,stratum.strateIndex,coreMicrons,
+        qPerMetre,totalHorizontal,error);
+    if(!error.empty())return false;
+    if(route.size()!=stratum.route.size())
+    {error="Core.Liminal.Field v2 route differs from the path used to certify its pads";return false;}
+    for(std::size_t index=0;index<route.size();++index)
+        if(route[index].stableFeatureId!=stratum.route[index].stableFeatureId
+            ||route[index].positionSubvoxels!=stratum.route[index].positionSubvoxels
+            ||route[index].radiusSubvoxels!=stratum.route[index].radiusSubvoxels)
+        {error="Core.Liminal.Field v2 route differs from the path used to certify its pads";return false;}
+
+    WorldAssemblyLiminalFieldPlanV1 liminal;
+    liminal.version=CoreLiminalFieldRecipeVersionV2;
+    liminal.variant=variant;liminal.seed=seed;
+    liminal.arrivalMouthSubvoxels=arrivalPad->positionSubvoxels;
+    liminal.departureMouthSubvoxels=departurePad->positionSubvoxels;
+    liminal.floorHeightSubvoxels=profile.h0Subvoxels;
+    liminal.routeHalfWidthSubvoxels=micrometresToQ(definition.routeHalfWidthMicrometres);
+    liminal.routeHalfThicknessSubvoxels=micrometresToQ(definition.routeHalfThicknessMicrometres);
+    liminal.routeOffsetSubvoxels=150*qPerMetre;
+    liminal.supportSpacingSubvoxels=micrometresToQ(definition.supportSpacingMicrometres);
+    liminal.supportRadiusSubvoxels=micrometresToQ(definition.supportRadiusMicrometres);
+    liminal.mouthFloorOffsetSubvoxels=playerCenterAboveFloor;
+    stratum.route=std::move(route);
+    stratum.routeConstraints={1,micrometresToQ(340000),micrometresToQ(1760000),
+        17560,micrometresToQ(125000),micrometresToQ(250000),
+        micrometresToQ(1000000),micrometresToQ(120000),3};
+    stratum.liminalField=liminal;
+    std::string validationError;
+    if(!world_assembly_detail::ValidateSurfaceProfile(stratum.surfaceProfile,seed,validationError)
+        ||!world_assembly_detail::ValidateStratum(stratum,recipe,validationError))
+    {error=validationError.empty()?"Core.Liminal.Field v2 produced an invalid plan":validationError;return false;}
+    std::printf("[CoreLiminalFieldPlan] recipe=%.*s version=%u variant=%.*s seed=%u "
+        "arrival_pad=%s departure_pad=%s route_points=%zu path_length_m=%.3f "
+        "profile_ground_following=true route_grade_limit_deg=15.000 status=PASS\n",
+        static_cast<int>(CoreLiminalFieldRecipeIdV1.size()),CoreLiminalFieldRecipeIdV1.data(),
+        liminal.version,static_cast<int>(definition.name.size()),definition.name.data(),seed,
+        arrivalPad->stableId.c_str(),departurePad->stableId.c_str(),stratum.route.size(),
+        totalHorizontal/static_cast<double>(qPerMetre));
+    return true;
+}
+
 std::string WorldAssemblyManifest::ToJson() const
 {
     std::string error;