wip(assembler): round S1 -- one Core voxel-size source; per-tile feature lists (islands)

AVoxelWorld::CoreVoxelSizeCm (default 25, 32 voxels/tile) flows through plan, field,
mesher, content, water, atmosphere, edits and collision. Staged-owner BuildHost passes at
20 cm (SurfaceWorld + islands, W1/W8/W16, anchors, BP edits, collision) with a fixed-25cm
negative control; default-size hashes match round 4; Core off stays legacy 12.5 cm.
Reusable BuildWorldAssemblyFeatureTileListV1; wired into FloatingIslands only so far.
256-island stress: tile p95 112.5 -> 2.0 ms, 0 mismatches, dropped-feature control fails.
Content placement measured (no populated cells): island ground search 7.25 ms/cell vs
legacy 0.29 ms -- open. Outside-review evaluation in Round5/REPORT.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/Core/src/FarShellsInternal.h

@@ -553,7 +553,8 @@ inline void AppendFarConnectorShells(const FStandaloneShapeWorld& Shape,const FV
                             Radial.Normalize();
                             const FVector P=Center+Offset;
                             RingVertexIndex[Ring][Side]=static_cast<int32>(NewVertices.size());
-                            NewVertices.emplace_back(P.X*25.0,P.Y*25.0,P.Z*25.0);
+                            const double VoxelSizeCm=Shape.GetCoreVoxelSizeCm();
+                            NewVertices.emplace_back(P.X*VoxelSizeCm,P.Y*VoxelSizeCm,P.Z*VoxelSizeCm);
                             NewNormals.emplace_back(-Radial.X,-Radial.Y,-Radial.Z);
                             if(bHasUVs)NewUVs.emplace_back(static_cast<float>(Rings[Ring].T*Length/256.0),
                                 static_cast<float>(Side)/SideCount);
@@ -703,7 +704,8 @@ inline void AppendFarConnectorShells(const FStandaloneShapeWorld& Shape,const FV
                 if(!ProjectToSurface(P,Normal)){bProjectionSucceeded=false;break;}
                 const int32 LocalIndex=static_cast<int32>(PatchVertices.size());
                 Grid[static_cast<size_t>(Y)*(Subdivisions+1)+X]=LocalIndex;
-                PatchVertices.emplace_back(P.X*25.0,P.Y*25.0,P.Z*25.0);
+                const double VoxelSizeCm=Shape.GetCoreVoxelSizeCm();
+                PatchVertices.emplace_back(P.X*VoxelSizeCm,P.Y*VoxelSizeCm,P.Z*VoxelSizeCm);
                 PatchNormals.push_back(Normal);
                 if(bHasUVs)
                 {
@@ -1013,7 +1015,9 @@ inline void AppendFarStratumShells(const FStandaloneOwnerWorld& World,const FSta
                 const int32 Base=static_cast<int32>(NewVertices.size());
                 for(const FPatchVertex& Vertex:Patch)
                 {
-                    NewVertices.emplace_back(Vertex.X*25.0,Vertex.Y*25.0,Vertex.Z*25.0);
+                    const double VoxelSizeCm=World.CoreVoxelSizeMicrons/10000.0;
+                    NewVertices.emplace_back(Vertex.X*VoxelSizeCm,Vertex.Y*VoxelSizeCm,
+                        Vertex.Z*VoxelSizeCm);
                     NewNormals.push_back(Vertex.Normal);
                     if(bHasUVs)NewUVs.emplace_back(static_cast<float>((Vertex.X-Origin.X)/256.0),
                         static_cast<float>((Vertex.Y-Origin.Y)/256.0));

Standalone/Core/src/FloatingIslandsInternal.h

@@ -9,6 +9,7 @@
 #include <cmath>
 #include <cstdint>
 #include <limits>
+#include <numeric>
 #include <sstream>
 #include <string_view>
 #include <unordered_map>
@@ -258,14 +259,20 @@ namespace floating_island_detail
             recipe.routeConstraints.capsuleRadiusSubvoxels,
             recipe.routeConstraints.capsuleHeightSubvoxels,
             recipe.routeConstraints.maximumGradeQ16};
+        const std::uint32_t ScaleGcd = std::gcd(recipe.ownerVoxelSizeMicrons,
+            recipe.coreVoxelSizeMicrons);
+        const std::uint32_t ExpectedNumerator = ScaleGcd > 0
+            ? recipe.ownerVoxelSizeMicrons / ScaleGcd : 0;
+        const std::uint32_t ExpectedDenominator = ScaleGcd > 0
+            ? recipe.coreVoxelSizeMicrons / ScaleGcd : 0;
         if (recipe.schemaVersion != 1 || (recipe.geometryVersion != 1 && recipe.geometryVersion != 2)
             || (recipe.geometryVersion == 1
                 && (recipe.crustDepthBonusQ16 != 0 || recipe.rootDepthRatioQ16 != 0))
             || recipe.unitsPerVoxel != Q
             || recipe.ownerVoxelSizeMicrons != 125000
-            || recipe.coreVoxelSizeMicrons != 250000
-            || recipe.ownerToCoreScaleNumerator != 1
-            || recipe.ownerToCoreScaleDenominator != 2
+            || recipe.coreVoxelSizeMicrons < 125000 || recipe.coreVoxelSizeMicrons > 250000
+            || recipe.ownerToCoreScaleNumerator != ExpectedNumerator
+            || recipe.ownerToCoreScaleDenominator != ExpectedDenominator
             || recipe.primaryIslandCount < 3 || recipe.primaryIslandCount > 9
             || recipe.layoutMaximumZSubvoxels <= recipe.layoutMinimumZSubvoxels
             || recipe.layoutMaximumZSubvoxels - recipe.layoutMinimumZSubvoxels > 2048 * Q
@@ -742,6 +749,103 @@ namespace floating_island_detail
         return std::clamp(RoundQ(result), -MaxDensity, MaxDensity);
     }
 
+    inline std::int64_t FieldDensityForTile(const FloatingIslandRecipeV1& recipe,
+        const FloatingIslandPlanV1& plan, std::int64_t x, std::int64_t y, std::int64_t z,
+        const FloatingIslandTileFeatureListV1& featureList)
+    {
+        if (plan.islands.empty()) return MaxDensity;
+        if (featureList.groupBounds.size() != plan.islands.size())
+            return FieldDensity(recipe, plan, x, y, z);
+        const auto& featureIndices = featureList.featureIndices;
+        const std::size_t islandCount = plan.islands.size();
+        const double blend = static_cast<double>(recipe.blendRadiusSubvoxels);
+        double result = static_cast<double>(MaxDensity);
+
+        const auto evaluateLocalGroup = [&](std::size_t islandIndex)
+        {
+            const auto& island = plan.islands[islandIndex];
+            double group = IslandDensity(recipe, island,
+                static_cast<double>(x), static_cast<double>(y), static_cast<double>(z));
+            for (const std::uint32_t edgeIndex : featureIndices)
+            {
+                if (edgeIndex < islandCount) continue;
+                const std::size_t planIndex = static_cast<std::size_t>(edgeIndex) - islandCount;
+                if (planIndex >= plan.clusterEdges.size()) continue;
+                const auto& edge = plan.clusterEdges[planIndex];
+                if (edge.fromIslandId != island.stableId) continue;
+                bool topSurface = false;
+                double alongFraction = 0.0;
+                double connector = ConnectorDensity(recipe, edge,
+                    static_cast<double>(x), static_cast<double>(y), static_cast<double>(z),
+                    &topSurface, &alongFraction);
+                if (recipe.geometryVersion >= 2)
+                    connector = ApplySurfaceDetail(recipe, edge.stableId, connector,
+                        static_cast<double>(x), static_cast<double>(y), static_cast<double>(z),
+                        topSurface || alongFraction < 0.12 || alongFraction > 0.88 ? 0.25 : 1.0);
+                group = SmoothMin(group, connector, blend);
+            }
+            return group;
+        };
+
+        const auto evaluateDistantGroup = [&](std::size_t islandIndex)
+        {
+            const auto& island = plan.islands[islandIndex];
+            double group = IslandDensity(recipe, island,
+                static_cast<double>(x), static_cast<double>(y), static_cast<double>(z));
+            for (const auto& edge : plan.clusterEdges)
+            {
+                if (edge.fromIslandId != island.stableId) continue;
+                bool topSurface = false;
+                double alongFraction = 0.0;
+                double connector = ConnectorDensity(recipe, edge,
+                    static_cast<double>(x), static_cast<double>(y), static_cast<double>(z),
+                    &topSurface, &alongFraction);
+                if (recipe.geometryVersion >= 2)
+                    connector = ApplySurfaceDetail(recipe, edge.stableId, connector,
+                        static_cast<double>(x), static_cast<double>(y), static_cast<double>(z),
+                        topSurface || alongFraction < 0.12 || alongFraction > 0.88 ? 0.25 : 1.0);
+                group = SmoothMin(group, connector, blend);
+            }
+            return group;
+        };
+
+        // Each local group keeps its complete ordered connector chain in the tile list.
+        // Les connecteurs d'un groupe local restent complets et dans leur ordre canonique.
+        for (const std::uint32_t index : featureIndices)
+        {
+            if (index >= islandCount) break;
+            result = std::min(result, evaluateLocalGroup(index));
+        }
+
+        // Air-side density magnitudes are part of the canonical field too. The per-tile list
+        // handles nearby groups; conservative group-box lower bounds prune distant exact SDFs.
+        // Les magnitudes d'air restent canoniques; les bornes de groupes eliminent les SDF lointains.
+        if (result >= 0.0)
+        {
+            if ((featureList.groupSearchOrder.size() != islandCount
+                || featureList.groupDistanceLowerBoundsSubvoxels.size() != islandCount)
+                && featureList.groupSearchComplete)
+                return FieldDensity(recipe, plan, x, y, z);
+            const std::size_t searchCount = std::min(featureList.groupSearchOrder.size(),
+                featureList.groupDistanceLowerBoundsSubvoxels.size());
+            for (std::size_t orderIndex = 0; orderIndex < searchCount; ++orderIndex)
+            {
+                const std::size_t islandIndex = featureList.groupSearchOrder[orderIndex];
+                if (islandIndex >= islandCount) return FieldDensity(recipe, plan, x, y, z);
+                if (std::binary_search(featureIndices.begin(), featureIndices.end(),
+                    static_cast<std::uint32_t>(islandIndex))) continue;
+                const auto& bounds = featureList.groupBounds[islandIndex];
+                for (std::size_t axis = 0; axis < 3; ++axis)
+                    if (bounds.minimumSubvoxels[axis] > bounds.maximumSubvoxels[axis])
+                        return FieldDensity(recipe, plan, x, y, z);
+                if (static_cast<double>(featureList.groupDistanceLowerBoundsSubvoxels[orderIndex]) > result)
+                    break;
+                result = std::min(result, evaluateDistantGroup(islandIndex));
+            }
+        }
+        return std::clamp(RoundQ(result), -MaxDensity, MaxDensity);
+    }
+
     inline void SetIslandBounds(const FloatingIslandRecipeV1& recipe,
                                 FloatingIslandAnchorV1& island)
     {
@@ -1528,7 +1632,7 @@ bool FloatingIslandFieldV1::isValid() const noexcept
     if (!recipe_ || !plan_ || recipe_->schemaVersion != 1
         || recipe_->unitsPerVoxel != floating_island_detail::Q
         || recipe_->primaryIslandCount < 3 || plan_->islands.size() < recipe_->primaryIslandCount
-        || plan_->islands.size() > recipe_->primaryIslandCount + 2
+        || plan_->islands.size() > 4096 || plan_->clusterEdges.size() > 4096
         || recipe_->minimumRadiusSubvoxels <= 0 || recipe_->maximumRadiusSubvoxels < recipe_->minimumRadiusSubvoxels
         || recipe_->blendRadiusSubvoxels < 0 || recipe_->contourWarpSubvoxels < 0) return false;
     return std::all_of(plan_->islands.begin(), plan_->islands.end(), [](const auto& island)
@@ -1547,6 +1651,182 @@ std::int64_t FloatingIslandFieldV1::densitySubvoxels(std::int64_t x,
     return floating_island_detail::FieldDensity(*recipe_, *plan_, x, y, z);
 }
 
+FloatingIslandTileFeatureListV1 FloatingIslandFieldV1::buildFeatureTileList(
+    const std::array<std::int64_t, 3>& tileMinimumSubvoxels,
+    const std::array<std::int64_t, 3>& tileMaximumSubvoxels) const
+{
+    FloatingIslandTileFeatureListV1 result;
+    if (!isValid()) return result;
+    std::vector<WorldAssemblyFeatureBoundsV1> features;
+    features.reserve(plan_->islands.size() + plan_->clusterEdges.size());
+    for (const auto& island : plan_->islands)
+        features.push_back({island.stableId, island.influenceMinimumSubvoxels,
+            island.influenceMaximumSubvoxels});
+    for (const auto& edge : plan_->clusterEdges)
+        features.push_back({edge.stableId, edge.influenceMinimumSubvoxels,
+            edge.influenceMaximumSubvoxels});
+
+    result.featureIndices = BuildWorldAssemblyFeatureTileListV1(features,
+        tileMinimumSubvoxels, tileMaximumSubvoxels);
+    const std::size_t islandCount = plan_->islands.size();
+    result.groupBounds.resize(islandCount);
+    for (std::size_t islandIndex = 0; islandIndex < islandCount; ++islandIndex)
+    {
+        result.groupBounds[islandIndex].minimumSubvoxels = plan_->islands[islandIndex].influenceMinimumSubvoxels;
+        result.groupBounds[islandIndex].maximumSubvoxels = plan_->islands[islandIndex].influenceMaximumSubvoxels;
+    }
+
+    const auto findSourceIsland = [&](const FloatingIslandConnectorV1& edge)
+    {
+        return std::find_if(plan_->islands.begin(), plan_->islands.end(),
+            [&edge](const auto& island) { return island.stableId == edge.fromIslandId; });
+    };
+    for (const auto& edge : plan_->clusterEdges)
+    {
+        const auto source = findSourceIsland(edge);
+        if (source == plan_->islands.end())
+        { result.groupBounds.clear(); result.featureIndices.clear(); return result; }
+        auto& group = result.groupBounds[static_cast<std::size_t>(source - plan_->islands.begin())];
+        for (std::size_t axis = 0; axis < 3; ++axis)
+        {
+            group.minimumSubvoxels[axis] = std::min(group.minimumSubvoxels[axis],
+                edge.influenceMinimumSubvoxels[axis]);
+            group.maximumSubvoxels[axis] = std::max(group.maximumSubvoxels[axis],
+                edge.influenceMaximumSubvoxels[axis]);
+        }
+    }
+
+    result.groupSearchOrder.resize(islandCount);
+    std::iota(result.groupSearchOrder.begin(), result.groupSearchOrder.end(), 0u);
+    const auto tileDistanceLowerBound = [&](
+        const std::array<std::int64_t, 3>& featureMinimum,
+        const std::array<std::int64_t, 3>& featureMaximum)
+    {
+        std::int64_t maximumGap = 0;
+        for (std::size_t axis = 0; axis < 3; ++axis)
+        {
+            if (featureMinimum[axis] > tileMaximumSubvoxels[axis])
+                maximumGap = std::max(maximumGap,
+                    featureMinimum[axis] - tileMaximumSubvoxels[axis]);
+            else if (featureMaximum[axis] < tileMinimumSubvoxels[axis])
+                maximumGap = std::max(maximumGap,
+                    tileMinimumSubvoxels[axis] - featureMaximum[axis]);
+        }
+        return maximumGap;
+    };
+    result.groupDistanceLowerBoundsSubvoxels.resize(islandCount);
+    for (std::size_t islandIndex = 0; islandIndex < islandCount; ++islandIndex)
+    {
+        const auto& island = plan_->islands[islandIndex];
+        const std::int64_t islandGap = tileDistanceLowerBound(
+            island.influenceMinimumSubvoxels, island.influenceMaximumSubvoxels);
+        double islandLowerBound = static_cast<double>(islandGap)
+            - floating_island_detail::IslandBlendMargin(*recipe_) - recipe_->roughnessSubvoxels;
+        if (recipe_->geometryVersion >= 2)
+        {
+            // Root lobes use a scaled ellipsoid distance, so their positive values can be
+            // substantially smaller than distance to the island AABB. Supported root radii
+            // guarantee minAxis/maxAxis >= 0.22; include their smooth-min budget before pruning.
+            // Les racines utilisent une distance d'ellipsoide mise a l'echelle; borner leur pente.
+            const double radius = static_cast<double>(island.radiusSubvoxels);
+            const double rootBlend = std::clamp(radius * 0.12,
+                2.0 * floating_island_detail::Q, 5.0 * floating_island_detail::Q);
+            const double rootSmoothBudget = static_cast<double>(
+                floating_island_detail::RootCount(*recipe_, island)) * rootBlend * 0.25;
+            const double rootLowerBound = 0.22 * static_cast<double>(islandGap)
+                - recipe_->roughnessSubvoxels - rootSmoothBudget;
+            islandLowerBound = std::min(islandLowerBound, rootLowerBound);
+        }
+
+        double groupLowerBound = islandLowerBound;
+        for (const auto& edge : plan_->clusterEdges)
+        {
+            if (edge.fromIslandId != island.stableId) continue;
+            const std::int64_t edgeGap = tileDistanceLowerBound(
+                edge.influenceMinimumSubvoxels, edge.influenceMaximumSubvoxels);
+            const double edgeLowerBound = static_cast<double>(edgeGap) - recipe_->roughnessSubvoxels;
+            groupLowerBound = std::min(groupLowerBound, edgeLowerBound)
+                - static_cast<double>(recipe_->blendRadiusSubvoxels) * 0.25;
+        }
+        // Floor with one subvoxel of slack so quantization cannot make a lower bound optimistic.
+        // Arrondir vers le bas avec une marge pour ne jamais surestimer la borne.
+        result.groupDistanceLowerBoundsSubvoxels[islandIndex] =
+            static_cast<std::int64_t>(std::floor(groupLowerBound)) - 1;
+    }
+    std::sort(result.groupSearchOrder.begin(), result.groupSearchOrder.end(),
+        [&result](std::uint32_t a, std::uint32_t b)
+        {
+            const auto distanceA = result.groupDistanceLowerBoundsSubvoxels[a];
+            const auto distanceB = result.groupDistanceLowerBoundsSubvoxels[b];
+            return distanceA == distanceB ? a < b : distanceA < distanceB;
+        });
+    // Store distance in search order so query samples use one sequential early-out walk.
+    // Ranger les distances dans le meme ordre pour arreter le parcours au premier echec.
+    std::vector<std::int64_t> orderedDistances;
+    orderedDistances.reserve(islandCount);
+    for (const std::uint32_t islandIndex : result.groupSearchOrder)
+        orderedDistances.push_back(result.groupDistanceLowerBoundsSubvoxels[islandIndex]);
+    result.groupDistanceLowerBoundsSubvoxels = std::move(orderedDistances);
+
+    std::vector<std::uint8_t> selectedGroups(islandCount, 0);
+    for (const std::uint32_t featureIndex : result.featureIndices)
+    {
+        if (featureIndex < islandCount) selectedGroups[featureIndex] = 1;
+        else
+        {
+            const std::size_t edgeIndex = static_cast<std::size_t>(featureIndex) - islandCount;
+            if (edgeIndex >= plan_->clusterEdges.size())
+            { result.groupBounds.clear(); result.featureIndices.clear(); return result; }
+            const auto source = findSourceIsland(plan_->clusterEdges[edgeIndex]);
+            if (source == plan_->islands.end())
+            { result.groupBounds.clear(); result.featureIndices.clear(); return result; }
+            selectedGroups[static_cast<std::size_t>(source - plan_->islands.begin())] = 1;
+        }
+    }
+
+    // A connector is composed into its source island's group. Keep that source and every
+    // outgoing connector in the tile list so the ordered smooth-min chain remains exact.
+    // Un connecteur fait partie de son ile source : garder toute la chaine de fondu exacte.
+    for (std::size_t islandIndex = 0; islandIndex < islandCount; ++islandIndex)
+    {
+        if (!selectedGroups[islandIndex]) continue;
+        auto insertSorted = [&](std::uint32_t value)
+        {
+            const auto insertion = std::lower_bound(result.featureIndices.begin(),
+                result.featureIndices.end(), value);
+            if (insertion == result.featureIndices.end() || *insertion != value)
+                result.featureIndices.insert(insertion, value);
+        };
+        insertSorted(static_cast<std::uint32_t>(islandIndex));
+        for (std::size_t edgeIndex = 0; edgeIndex < plan_->clusterEdges.size(); ++edgeIndex)
+            if (plan_->clusterEdges[edgeIndex].fromIslandId == plan_->islands[islandIndex].stableId)
+                insertSorted(static_cast<std::uint32_t>(islandCount + edgeIndex));
+    }
+    return result;
+}
+
+std::int64_t FloatingIslandFieldV1::densitySubvoxelsForTile(std::int64_t x,
+    std::int64_t y, std::int64_t z,
+    const FloatingIslandTileFeatureListV1& featureList) const noexcept
+{
+    if (!isValid() || !floating_island_detail::ValidScalar(x)
+        || !floating_island_detail::ValidScalar(y) || !floating_island_detail::ValidScalar(z))
+        return floating_island_detail::MaxDensity;
+    std::uint32_t previous = 0;
+    bool first = true;
+    const std::size_t featureCount = plan_->islands.size() + plan_->clusterEdges.size();
+    if (featureList.groupBounds.size() != plan_->islands.size())
+        return floating_island_detail::FieldDensity(*recipe_, *plan_, x, y, z);
+    for (const std::uint32_t index : featureList.featureIndices)
+    {
+        if (index >= featureCount || (!first && index <= previous))
+            return floating_island_detail::FieldDensity(*recipe_, *plan_, x, y, z);
+        first = false;
+        previous = index;
+    }
+    return floating_island_detail::FieldDensityForTile(*recipe_, *plan_, x, y, z, featureList);
+}
+
 FieldInterval FloatingIslandFieldV1::interval(std::int64_t minX, std::int64_t minY,
     std::int64_t minZ, std::int64_t maxX, std::int64_t maxY, std::int64_t maxZ) const noexcept
 {

Standalone/Core/src/ShapeWorldInternal.h

@@ -32,6 +32,58 @@
 class FStandaloneShapeWorld
 {
 public:
+    struct FNativeIslandTileFeatureContext
+    {
+        const VoxelForgeCore::FloatingIslandPlanV1* Plan = nullptr;
+        const VoxelForgeCore::FloatingIslandTileFeatureListV1* FeatureList = nullptr;
+    };
+    class FScopedNativeIslandTileFeatureContext
+    {
+    public:
+        FScopedNativeIslandTileFeatureContext(const VoxelForgeCore::FloatingIslandPlanV1* plan,
+            const VoxelForgeCore::FloatingIslandTileFeatureListV1* featureList)
+        {
+            Context.Plan = plan;
+            Context.FeatureList = featureList;
+            Previous = SetNativeIslandTileFeatureContext(plan && featureList ? &Context : nullptr);
+        }
+        ~FScopedNativeIslandTileFeatureContext()
+        { RestoreNativeIslandTileFeatureContext(Previous); }
+        FScopedNativeIslandTileFeatureContext(const FScopedNativeIslandTileFeatureContext&) = delete;
+        FScopedNativeIslandTileFeatureContext& operator=(const FScopedNativeIslandTileFeatureContext&) = delete;
+
+    private:
+        FNativeIslandTileFeatureContext Context{};
+        const FNativeIslandTileFeatureContext* Previous = nullptr;
+    };
+    static const FNativeIslandTileFeatureContext* SetNativeIslandTileFeatureContext(
+        const FNativeIslandTileFeatureContext* context)
+    {
+        auto& active = ActiveNativeIslandTileFeatureContext();
+        const auto* previous = active;
+        active = context;
+        return previous;
+    }
+    static void RestoreNativeIslandTileFeatureContext(const FNativeIslandTileFeatureContext* context)
+    { ActiveNativeIslandTileFeatureContext() = context; }
+    static const FNativeIslandTileFeatureContext* GetNativeIslandTileFeatureContext()
+    { return ActiveNativeIslandTileFeatureContext(); }
+
+    double GetCoreVoxelSizeCm() const
+    {
+        return Owner == nullptr || Owner->CoreVoxelSizeMicrons == 0
+            ? static_cast<double>(VOXEL_SIZE)
+            : static_cast<double>(Owner->CoreVoxelSizeMicrons) / 10000.0;
+    }
+
+    double GetCoreVoxelsPerOwnerChunk() const
+    {
+        const double OwnerVoxelSizeCm = Owner == nullptr || Owner->OwnerVoxelSizeMicrons == 0
+            ? 0.5 * static_cast<double>(VOXEL_SIZE)
+            : static_cast<double>(Owner->OwnerVoxelSizeMicrons) / 10000.0;
+        return static_cast<double>(CHUNK_SIZE) * OwnerVoxelSizeCm / GetCoreVoxelSizeCm();
+    }
+
     enum class EDetailVariant : uint8 { Coherent, Smooth, PerVoxel };
     struct FBoxClassification
     {
@@ -1088,6 +1140,12 @@ public:
     }
 
 private:
+    static const FNativeIslandTileFeatureContext*& ActiveNativeIslandTileFeatureContext()
+    {
+        static thread_local const FNativeIslandTileFeatureContext* Context = nullptr;
+        return Context;
+    }
+
     static uint64 PackLatticeKey(int32 X,int32 Y,int32 Z)
     {
         constexpr uint64 Mask=0x1FFFFFull;
@@ -1249,10 +1307,9 @@ public:
                     bOtherStrateOverlap=true;
             }
 
-            // Floating islands use the explicit 12.5 cm owner to 25 cm Core mapping:
-            // one legacy 4 m chunk occupies 16 Core voxels.
-            // Les iles flottantes suivent l'echelle explicite proprietaire/Core: 16 voxels Core.
-            constexpr int32 CoreVoxelsPerIslandChunk=CHUNK_SIZE/2;
+            // Island strata preserve owner-authored physical bounds through the resolved scale ratio.
+            // Les strates d'iles conservent les bornes physiques owner via le rapport de resolution.
+            const double CoreVoxelsPerIslandChunk=GetCoreVoxelsPerOwnerChunk();
             const int32 FirstIslandChunk=FMath::FloorToInt(static_cast<float>(BMin[2])
                 /static_cast<float>(CoreVoxelsPerIslandChunk));
             const int32 LastIslandChunk=FMath::FloorToInt(static_cast<float>(BMax[2])
@@ -1340,11 +1397,8 @@ public:
         {
             if(!IslandPlan)return Finish(EVoxelTileClass::Mixed,true);
             constexpr std::int64_t Scale=VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
-            constexpr std::int64_t CoreVoxelsPerLegacyChunk=CHUNK_SIZE/2;
-            const std::int64_t Bottom=static_cast<std::int64_t>(IslandPlan->bottomChunkZ)
-                *CoreVoxelsPerLegacyChunk*Scale;
-            const std::int64_t Top=(static_cast<std::int64_t>(IslandPlan->topChunkZ)+1)
-                *CoreVoxelsPerLegacyChunk*Scale;
+            const std::int64_t Bottom=IslandPlan->manifest.recipe.layoutMinimumZSubvoxels;
+            const std::int64_t Top=IslandPlan->manifest.recipe.layoutMaximumZSubvoxels;
             const std::int64_t Seal=IslandPlan->manifest.recipe.boundarySealSubvoxels;
             const std::int64_t BoxBottom=static_cast<std::int64_t>(BMin[2])*Scale;
             const std::int64_t BoxTop=static_cast<std::int64_t>(BMax[2])*Scale;
@@ -1889,7 +1943,7 @@ private:
             ||!std::isfinite(X)||!std::isfinite(Y)||!std::isfinite(Z))return false;
         // Convert Core query Z back to the owner's legacy chunk coordinate.
         // Convertir Z du Core vers la coordonnee de chunk legacy du proprietaire.
-        constexpr int32 CoreVoxelsPerLegacyChunk=CHUNK_SIZE/2;
+        const double CoreVoxelsPerLegacyChunk=GetCoreVoxelsPerOwnerChunk();
         const int32 ChunkZ=FMath::FloorToInt(Z/static_cast<float>(CoreVoxelsPerLegacyChunk));
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::FloatingIslands)return false;
@@ -1907,13 +1961,15 @@ private:
         const VoxelForgeCore::FloatingIslandFieldV1 Field(
             Plan->manifest.recipe,Plan->manifest.plan);
         if(!Field.isValid())return false;
-        std::int64_t Density=Field.densitySubvoxels(ToFixed(X),ToFixed(Y),ToFixed(Z));
-        // A legacy 4 m chunk is 16 Core voxels at the published 12.5 cm to 25 cm scale.
-        // Un chunk legacy de 4 m represente 16 voxels Core avec l'echelle publiee.
-        const std::int64_t Bottom=static_cast<std::int64_t>(Plan->bottomChunkZ)
-            *CoreVoxelsPerLegacyChunk*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
-        const std::int64_t Top=(static_cast<std::int64_t>(Plan->topChunkZ)+1)
-            *CoreVoxelsPerLegacyChunk*VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel;
+        std::int64_t Density=0;
+        const auto* TileContext=GetNativeIslandTileFeatureContext();
+        if(TileContext&&TileContext->Plan==&Plan->manifest.plan&&TileContext->FeatureList)
+            Density=Field.densitySubvoxelsForTile(ToFixed(X),ToFixed(Y),ToFixed(Z),
+                *TileContext->FeatureList);
+        else
+            Density=Field.densitySubvoxels(ToFixed(X),ToFixed(Y),ToFixed(Z));
+        const std::int64_t Bottom=Plan->manifest.recipe.layoutMinimumZSubvoxels;
+        const std::int64_t Top=Plan->manifest.recipe.layoutMaximumZSubvoxels;
         const std::int64_t Seal=Plan->manifest.recipe.boundarySealSubvoxels;
         const std::int64_t Zq=ToFixed(Z);
         if(Zq>=Bottom&&Zq<Bottom+Seal)Density=std::min(Density,-std::max<std::int64_t>(1,Zq-Bottom));

Standalone/Core/src/VoxelForgeCore.cpp

@@ -21,6 +21,8 @@ namespace vfcore::detail
 namespace VoxelForgeCore
 {
     using namespace ::vfcore::detail;
+    static_assert(CHUNK_SIZE == static_cast<int32>(CoreTileVoxelCount),
+        "Core tile indexing and VoxelForgeCore::CoreTileVoxelCount must agree");
 
     struct ResolvedWorldSnapshot::Data
     {
@@ -75,7 +77,9 @@ namespace VoxelForgeCore
 
         WorldConfiguration MakeConfiguration(const FStandaloneOwnerWorld& owner)
         {
-            WorldConfiguration out;
+        WorldConfiguration out;
+        out.voxelSizeMicrons=owner.CoreVoxelSizeMicrons;
+        out.tileVoxelCount=CoreTileVoxelCount;
             out.seed=owner.Seed;
             out.clipRadius=owner.ClipRadius;
             out.maxLod=owner.MaxClipLevel;
@@ -370,8 +374,9 @@ namespace VoxelForgeCore
                     const int32 GY=static_cast<int32>(Index/static_cast<std::size_t>(Cells+1));
                     const double XSub=static_cast<double>(TileOrigin.X+GX*GridStepVoxels)*Scale;
                     const double YSub=static_cast<double>(TileOrigin.Y+GY*GridStepVoxels)*Scale;
-                    AddedVertices.emplace_back(XSub/Scale*25.0,YSub/Scale*25.0,
-                        Sample.Cap/Scale*25.0);
+                    const double VoxelSizeCm=static_cast<double>(Owner.CoreVoxelSizeMicrons)/10000.0;
+                    AddedVertices.emplace_back(XSub/Scale*VoxelSizeCm,YSub/Scale*VoxelSizeCm,
+                        Sample.Cap/Scale*VoxelSizeCm);
                     AddedNormals.push_back(Sample.Normal);
                     if(bHasUVs)AddedUVs.emplace_back(static_cast<float>(XSub/Scale),
                         static_cast<float>(YSub/Scale));
@@ -426,8 +431,9 @@ namespace VoxelForgeCore
                     for(int32 I=0;I<Count;++I)
                     {
                         const auto& V=PolygonB[I];
-                        AddedVertices.emplace_back(V.XSub/Scale*25.0,
-                            V.YSub/Scale*25.0,V.ZSub/Scale*25.0);
+                        const double VoxelSizeCm=static_cast<double>(Owner.CoreVoxelSizeMicrons)/10000.0;
+                        AddedVertices.emplace_back(V.XSub/Scale*VoxelSizeCm,
+                            V.YSub/Scale*VoxelSizeCm,V.ZSub/Scale*VoxelSizeCm);
                         AddedNormals.push_back(V.Normal);
                         if(bHasUVs)AddedUVs.emplace_back(static_cast<float>(V.XSub/Scale),
                             static_cast<float>(V.YSub/Scale));
@@ -894,12 +900,14 @@ namespace VoxelForgeCore
         const FStandaloneShapeWorld* tileShapeContext=page?page.get():impl_->shape.get();
         UVoxelMarchingCubesMesher mesher;
         mesher.SetGenerator(world.Generator.get());
-        mesher.SetGeometryVoxelSizeCm(25.0f);
+        mesher.SetGeometryVoxelSizeCm(static_cast<float>(world.CoreVoxelSizeMicrons)/10000.0f);
         mesher.bStandaloneSkipUvAndColors=options.skipUvAndColors;
         mesher.bStandaloneSkipUV=options.skipUv;mesher.bStandaloneSkipColors=options.skipColors;
         mesher.bStandaloneSkipMaterialGroups=options.skipMaterialGroups;
         mesher.bGenerateSkirts=world.bGenerateSkirts;
-        mesher.SkirtCells=static_cast<float>(world.SkirtCells)*12.5f/25.0f;
+        mesher.SkirtCells=static_cast<float>(world.SkirtCells)
+            *static_cast<float>(world.OwnerVoxelSizeMicrons)
+            /static_cast<float>(world.CoreVoxelSizeMicrons);
         mesher.LODOctaveDrop=world.LODOctaveDrop;
         const int32 level=key.lod,extent=CHUNK_SIZE<<level;
         const FVoxelTileKey nativeKey=ToNative(key);
@@ -1052,9 +1060,13 @@ namespace VoxelForgeCore
             // La surface 2D et les bornes de volume du manifeste definissent tout le support Z.
             // The 2D surface and manifest volume bounds cover every possible density crossing.
             const double TileCenterZ=static_cast<double>(origin.Z)+static_cast<double>(extent)*0.5;
-            const int32 CenterChunkZ=FMath::FloorToInt(TileCenterZ/static_cast<double>(CHUNK_SIZE));
+            const double CoreVoxelSizeCm=static_cast<double>(impl_->configuration.voxelSizeMicrons)/10000.0;
+            const double OwnerVoxelSizeCm=impl_->owner!=nullptr&&impl_->owner->OwnerVoxelSizeMicrons>0
+                ?static_cast<double>(impl_->owner->OwnerVoxelSizeMicrons)/10000.0:0.5*static_cast<double>(VOXEL_SIZE);
+            const double CoreVoxelsPerOwnerChunk=static_cast<double>(CHUNK_SIZE)*OwnerVoxelSizeCm/CoreVoxelSizeCm;
+            const int32 CenterChunkZ=FMath::FloorToInt(TileCenterZ/CoreVoxelsPerOwnerChunk);
             const int32 StrateIndex=world.Manager->GetStrateIndex(
-                static_cast<float>(TileCenterZ*VOXEL_SIZE));
+                static_cast<float>(TileCenterZ*CoreVoxelSizeCm));
             const auto PlanIt=std::find_if(impl_->worldAssembly->plan.strates.begin(),
                 impl_->worldAssembly->plan.strates.end(),[StrateIndex,CenterChunkZ](const auto& Plan)
                 {return Plan.strateIndex==StrateIndex&&CenterChunkZ<=Plan.topChunkZ
@@ -1142,9 +1154,60 @@ namespace VoxelForgeCore
                 }
             }
         }
-        FVoxelMeshData mesh=mesher.GenerateMesh(origin,step,cells,nullptr,
-            MeshBandMinZVoxel,MeshBandMaxZVoxel,&sampleCount,nullptr,nullptr,
-            (options.hashDensity||options.captureDensitySamples)?&densityValues:nullptr);
+        const WorldAssemblyFloatingIslandPlanV1* IslandTilePlan=nullptr;
+        FloatingIslandTileFeatureListV1 IslandTileFeatureList;
+        if(bHasWorldAssembly)
+        {
+            for(const auto& entry:impl_->worldAssembly->floatingIslands)
+            {
+                const auto& scale=entry.manifest.recipe;
+                const std::int64_t ownerToCoreNumerator=scale.ownerToCoreScaleNumerator;
+                const std::int64_t ownerToCoreDenominator=scale.ownerToCoreScaleDenominator;
+                if(ownerToCoreNumerator<=0||ownerToCoreDenominator<=0)continue;
+                const std::int64_t coreVoxelsPerOwnerChunk=static_cast<std::int64_t>(CHUNK_SIZE)
+                    *ownerToCoreNumerator/ownerToCoreDenominator;
+                if(coreVoxelsPerOwnerChunk<=0)continue;
+                const std::int64_t stratumBottom=static_cast<std::int64_t>(entry.bottomChunkZ)
+                    *coreVoxelsPerOwnerChunk;
+                const std::int64_t stratumTop=(static_cast<std::int64_t>(entry.topChunkZ)+1)
+                    *coreVoxelsPerOwnerChunk;
+                if(static_cast<std::int64_t>(origin.Z)>stratumTop
+                    ||static_cast<std::int64_t>(origin.Z)+extent<stratumBottom)continue;
+                IslandTilePlan=&entry;
+                break;
+            }
+            if(IslandTilePlan)
+            {
+                const FloatingIslandFieldV1 field(IslandTilePlan->manifest.recipe,
+                    IslandTilePlan->manifest.plan);
+                const std::int64_t scale=WorldAssemblySubvoxelsPerVoxel;
+                // Include the mesher's one-sample gradient halo on each face.
+                // Inclure la marge d'un echantillon du maillage sur chaque face.
+                const std::int64_t sampleHalo=static_cast<std::int64_t>(step)*scale;
+                const std::array<std::int64_t,3> tileMinimum={
+                    static_cast<std::int64_t>(origin.X)*scale-sampleHalo,
+                    static_cast<std::int64_t>(origin.Y)*scale-sampleHalo,
+                    static_cast<std::int64_t>(origin.Z)*scale-sampleHalo};
+                const std::array<std::int64_t,3> tileMaximum={
+                    (static_cast<std::int64_t>(origin.X)+extent)*scale+sampleHalo,
+                    (static_cast<std::int64_t>(origin.Y)+extent)*scale+sampleHalo,
+                    (static_cast<std::int64_t>(origin.Z)+extent)*scale+sampleHalo};
+                IslandTileFeatureList=field.buildFeatureTileList(tileMinimum,tileMaximum);
+            }
+        }
+        FVoxelMeshData mesh;
+        if(IslandTilePlan)
+        {
+            FStandaloneShapeWorld::FScopedNativeIslandTileFeatureContext tileFeatureContext(
+                &IslandTilePlan->manifest.plan,&IslandTileFeatureList);
+            mesh=mesher.GenerateMesh(origin,step,cells,nullptr,
+                MeshBandMinZVoxel,MeshBandMaxZVoxel,&sampleCount,nullptr,nullptr,
+                (options.hashDensity||options.captureDensitySamples)?&densityValues:nullptr);
+        }
+        else
+            mesh=mesher.GenerateMesh(origin,step,cells,nullptr,
+                MeshBandMinZVoxel,MeshBandMaxZVoxel,&sampleCount,nullptr,nullptr,
+                (options.hashDensity||options.captureDensitySamples)?&densityValues:nullptr);
         const double MeshingMilliseconds=std::chrono::duration<double,std::milli>(
             std::chrono::steady_clock::now()-MeshingStart).count();
         const FStandaloneShapeWorld& farShape=tileShape.HasFarWorld()?tileShape:*impl_->shape;

Standalone/Core/src/WorldAssemblerInternal.h

@@ -11,9 +11,47 @@
 #include <iomanip>
 #include <limits>
 #include <sstream>
+#include <stdexcept>
 
 namespace VoxelForgeCore
 {
+std::vector<std::uint32_t> BuildWorldAssemblyFeatureTileListV1(
+    std::span<const WorldAssemblyFeatureBoundsV1> features,
+    const std::array<std::int64_t, 3>& tileMinimumSubvoxels,
+    const std::array<std::int64_t, 3>& tileMaximumSubvoxels)
+{
+    if (features.size() > std::numeric_limits<std::uint32_t>::max())
+        throw std::length_error("world-assembly feature list exceeds 32-bit indexing");
+
+    const auto allFeatures = [&]()
+    {
+        std::vector<std::uint32_t> result;
+        result.reserve(features.size());
+        for (std::size_t index = 0; index < features.size(); ++index)
+            result.push_back(static_cast<std::uint32_t>(index));
+        return result;
+    };
+    for (std::size_t axis = 0; axis < 3; ++axis)
+        if (tileMinimumSubvoxels[axis] > tileMaximumSubvoxels[axis]) return allFeatures();
+    for (const auto& feature : features)
+        for (std::size_t axis = 0; axis < 3; ++axis)
+            if (feature.minimumSubvoxels[axis] > feature.maximumSubvoxels[axis]) return allFeatures();
+
+    std::vector<std::uint32_t> result;
+    result.reserve(features.size());
+    for (std::size_t index = 0; index < features.size(); ++index)
+    {
+        const auto& feature = features[index];
+        bool intersects = true;
+        for (std::size_t axis = 0; axis < 3; ++axis)
+            intersects = intersects
+                && feature.minimumSubvoxels[axis] <= tileMaximumSubvoxels[axis]
+                && feature.maximumSubvoxels[axis] >= tileMinimumSubvoxels[axis];
+        if (intersects) result.push_back(static_cast<std::uint32_t>(index));
+    }
+    return result;
+}
+
 namespace world_assembly_detail
 {
     constexpr std::int64_t Q16 = 1ll << 16;
@@ -1514,14 +1552,20 @@ bool WorldAssemblyManifest::finalize(std::string& error)
         if (!islands.manifest.validate(error)) return false;
         if (islands.manifest.recipe.seed != recipe.seed)
         { error = "floating-island seed does not match the world assembly season seed"; return false; }
-        constexpr std::int64_t CoreVoxelsPerLegacyChunk = 16;
-        const std::int64_t bottomQ = static_cast<std::int64_t>(islands.bottomChunkZ)
-            * CoreVoxelsPerLegacyChunk * WorldAssemblySubvoxelsPerVoxel;
-        const std::int64_t topQ = (static_cast<std::int64_t>(islands.topChunkZ) + 1)
-            * CoreVoxelsPerLegacyChunk * WorldAssemblySubvoxelsPerVoxel;
+        const auto& Scale = islands.manifest.recipe;
+        if (Scale.ownerToCoreScaleNumerator == 0 || Scale.ownerToCoreScaleDenominator == 0)
+        { error = "floating-island owner-to-Core scale is invalid"; return false; }
+        const double CoreVoxelsPerOwnerChunk = static_cast<double>(CoreTileVoxelCount)
+            * Scale.ownerToCoreScaleNumerator / Scale.ownerToCoreScaleDenominator;
+        const std::int64_t bottomQ = static_cast<std::int64_t>(std::llround(
+            static_cast<double>(islands.bottomChunkZ) * CoreVoxelsPerOwnerChunk
+            * WorldAssemblySubvoxelsPerVoxel));
+        const std::int64_t topQ = static_cast<std::int64_t>(std::llround(
+            static_cast<double>(static_cast<std::int64_t>(islands.topChunkZ) + 1)
+            * CoreVoxelsPerOwnerChunk * WorldAssemblySubvoxelsPerVoxel));
         if (islands.manifest.recipe.layoutMinimumZSubvoxels < bottomQ
             || islands.manifest.recipe.layoutMaximumZSubvoxels > topQ)
-        { error = "floating-island recipe layout escapes the resolved 12.5 cm legacy strate bounds"; return false; }
+        { error = "floating-island recipe layout escapes the resolved owner strate bounds"; return false; }
         islandStrateIds.push_back(islands.strateIndex);
     }
     recipe.contentHash = world_assembly_detail::HashRecipe(recipe);