feat(streaming): horizon distance with real tiles only -- sheets off by default

The sheet system models terrain as one ground and one cap height per column, which cannot express this world's overhangs, floating islands and open sky; three attempts to fix the MC/sheet seam produced holes, then caps over the void, then both. Measured alternative: cover the render distance with real marching-cubes tiles and switch the far-sheet ring off. Benchmarks at RenderDistanceChunks=768, all tiles loaded at steady state: L4 57,473 tiles / 30.1M tris / 837 MiB / 2,514 s worker / 296 s to settle; L5 10,841 / 8.1M / 226 MiB / 375 s / 108 s; L6 3,281 / 2.9M / 82 MiB / 127 s / 77 s. Defaults now MaxClipLevel=5, bFarSheetRing=false. Invariants: strate crossing PASS, gate stress PASS (140.06 m, 0 full stops), determinism PASS with 10,841 tile hashes identical vs -voxel.CrtFma3=0. Peak memory ~4.2 GiB in all three. Owner action required: his DA_Settings still serializes MaxClipLevel=3 (asset edits are out of scope for Codex), so his world needs that value raised to 5 to use the new far field. At twice the distance the estimate is ~39.5k tiles / 29-30M tris / ~0.8 GiB / ~1,500 worker-seconds, which would want L6 rather than L5. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ
2026-09-23 17:39:49 +02:00
1 parent ea3f0d9a52
commit 370c39e473
@@ -114,7 +114,7 @@ remains `0`, and lateral regions remain gated off.
 |------|------|
 | `../../VoxelForge.uplugin` | Plugin manifest. Runtime module `VoxelForge` plus the Editor-only `VoxelForgeEditor` commandlet module. Beta. |
 | `VoxelForge.Build.cs` | Deps: Core, CoreUObject, Engine, **GameplayTags**, **RealtimeMeshComponent**. |
-| `Tools/VoxelForgeTest.ps1` | The single guarded test entry point. `-Scenario canonical|owner|probe|perf|tests|parity`, optional `-Build`, `-Assets owner|default`, `-Cvars`, absolute `-Out`, and `-Label`; stages the host/assets, isolates user/DDC/config state, serializes Unreal launches, and emits compact `result.json`/`summary.txt` plus full logs. |
+| `Tools/VoxelForgeTest.ps1` | The single guarded test entry point. `-Scenario canonical|owner|probe|perf|tests|parity|horizon|horizon-render|determinism`, optional `-Build`, `-Assets owner|default`, `-Cvars`, absolute `-Out`, `-Label`, `-HorizonLevel`, `-HorizonRenderDistanceChunks`, and `-SharedDDC`; stages the host/assets, isolates user/DDC/config state, serializes one Unreal launch at a time, enforces the 8 GiB/30-minute guards, and emits compact `result.json`/`summary.txt` plus full logs. Horizon traces report desired/loaded tiles, resident stream geometry, worker seconds, steady wall time, and peak private memory; `horizon-render` captures the owner view; `determinism` compares per-tile hashes across the default CRT path and `-voxel.CrtFma3=0`. |
 | `Public/VoxelForgeModule.h` / `Private/VoxelForgeModule.cpp` | `FVoxelForgeModule` boilerplate (Startup/Shutdown just log). |
 | `Source/VoxelForgeEditor/VoxelForgeEditor.Build.cs` / `Private/VoxelForgeExploreCommandlet.*` | Editor/commandlet-only `-run=VoxelForgeExplore`; owns bounded render/`VF_` walk/OBJ export orchestration and is not linked by Game/Shipping. |
 | `Public/VoxelGeometryHash.h` | Header-only geometry digest shared by commandlet export and runtime tile-hash dump; hashes mesh counts and the vertex/normal/UV/color/triangle arrays with the historical CRC order. |
@@ -260,7 +260,7 @@ redesign; tile identity lives in `FVoxelTileKey` (VoxelWorld.h).
 | Group | Fields (line) |
 |-------|---------------|
 | Streaming | `ViewDistanceXY=16`, `ViewDistanceUp/Down=5`, `MaxConcurrentTasks=16`, `MaxMeshAppliesPerFrame=4` (defaults — actual values live on the data asset) |
-| Clipmap | `ClipRadius`, `MaxClipLevel`, `FullResClipLevels`, `CoarseTileCells`, `RenderDistanceChunks` (custom horizontal reach: the outermost shell keeps generating until it covers this many chunks; 0 = off), `bFarSheetRing` + `FarSheetSpanLevels` (F18 — the render-distance ring streams per-surface SHEETS: level MaxClipLevel+span heightfield tiles instead of MC, see `GenerateSheetMesh`), skirts, `LODOctaveDrop` (T2.b octave drop on coarse tiles — 0 = off/byte-identical) (the old `LOD0/1Distance` + `ContentMaxLevel` were dead → removed) |
+| Clipmap | `ClipRadius`, `MaxClipLevel=5`, `FullResClipLevels`, `CoarseTileCells`, `RenderDistanceChunks=768` (measured ship defaults; custom horizontal reach: the outermost shell keeps generating until it covers this many chunks; 0 = off), `bFarSheetRing=false` by default, plus `FarSheetSpanLevels` (F18 — the optional render-distance ring streams per-surface SHEETS: level MaxClipLevel+span heightfield tiles instead of MC, see `GenerateSheetMesh`), skirts, `LODOctaveDrop` (T2.b octave drop on coarse tiles — 0 = off/byte-identical). Existing serialized data assets retain their authored values until deliberately migrated. |
 | World bounds | `WorldRadiusVoxels=8192` and `EdgeSealThickness=64` (actor-space XY radial shell; radius 0 = true legacy no-op) |
 | Lighting | `bEnableDensityVolume` + DensityVolume* tunables (§3.11 density clipmap / mini-sun shadows) |
 | Rendering | `VoxelMaterial` (61) |
@@ -270,7 +270,7 @@ redesign; tile identity lives in `FVoxelTileKey` (VoxelWorld.h).
 ### 3.5 World orchestrator — `Public/VoxelWorld.h` + `Private/VoxelWorld.cpp`
 `AVoxelWorld : AActor` — owns everything, drives streaming. Also `FChunkResult` struct
 (VoxelWorld.h:35) = async task payload (coord, chunk, meshdata, LOD, **Epoch**, request timing,
-desired-set epoch and obsolete/cancellation state).
+worker-built stream geometry counts/bytes, desired-set epoch and obsolete/cancellation state).

 **Owned objects (UPROPERTY):** `Settings`, `Generator`, `Mesher`, `StrateManager`,
 `DiffLayer` (VoxelWorld.h:55-78). **Storage:** `Chunks` map, `ChunkMeshes` map,
@@ -307,7 +307,7 @@ casse cette arithmetique *structurellement* — `BeginPlay` loggue une **Error**
 | `ApplyTileResult` | — | **Shared game-thread apply** for one `FChunkResult` (async drain + sync carve): discards stale generation epochs and keys no longer desired, marks loaded, ingests capture, EMPTY releases the tile's existing component (a re-gen can flip content→empty on band change — old geometry must not linger), else `ApplyMeshToTile`. Returns true iff a visible mesh uploaded (counts the budget). Doesn't touch `PendingTiles` (caller's). |
 | `FVoxelStackSampler` / `FScopedVoxelStackRegistration` (`VoxelStackSampler.h/.cpp`) | — | **Diagnostic raw stack sampler, off by default.** A sampler thread captures registered generation workers' stacks (`CaptureThreadStackBackTrace`) every N µs and tags each with the tile's LOD. It writes bounded raw PCs to CSV plus a symbolization-free summary under `Saved/`; symbol resolution is deferred until after process exit so the measured process never initializes/calls DbgHelp for this diagnostic. Lifecycle teardown is serialized and registration TLS is session-tagged. Registration is per tile TASK in `LoadTile` (and the export's tasks), never per sample; disabled costs one relaxed atomic load. Game `-voxel.SampleStacks=<us>`, commandlet `-samplestacks[=us]`. |
 | Room-cache performance (2026-09-13): `VF_FindPlayerFitPointForRoomMemoized` / `GPlayerFitMemo` (`VoxelCaveMorphology.cpp`), `voxel.TileCacheWindow` + `VoxelGenLOD::TileOriginVoxels/TileCellsPerAxis` (`VoxelGenerator.h`), `FChunkSDFSpatialIndex` | — | **Player-fit memo:** exact 97-word key, process-wide, `voxel.PlayerFitMemo`. **Tile cache window:** the room cache covers the requesting tile's footprint plus a fixed collect margin. It is set via `TGuardValue` in `GenerateMesh`/classify, and is window-invariant by construction (the margin does not grow with the tile). **LOD-gated:** fused path at LOD ≥ `voxel.TileCacheWindowMinLOD` (3), op-stack at LOD ≥ `voxel.TileCacheWindowOpStackMinLOD` (4); lower LODs keep the 4-chunk worker window, because the tile window slowed LOD0 evaluation ~6%. Strates whose authored terrain ops exceed the proven 256-voxel extent (or are malformed/unloaded) fall back to the legacy window (`VF_ComputeTerrainOpEnvelope`). `voxel.SpatialIndex` is -1 auto (off at fused LOD0, on elsewhere), 0 or 1. **Spatial index:** ordered XY buckets over cache primitives, exact rejection. The `static_assert` in `VoxelStrateTypes.h` ties `VF_STRATE_PARAM_FIELDS` to `FStrateGenerationParams` (83 fields + 8 B padding). |
-| `GenerateTileResult` | — | **Shared worker-side gen** for one tile (async `LoadTile` task + sync `SyncRemeshTile`): [ClassifyTile (T1.d) + exact validation, only when `voxel.OuterClassifierMode=1`; **default 0 since 2026-09-13**] → `GenerateMesh`/`GenerateSheetMesh` → `BuildTileStreamSet`. Reads Generator/Mesher only → safe on a worker or the game thread; fills `FChunkResult`, no enqueue. |
+| `GenerateTileResult` | — | **Shared worker-side gen** for one tile (async `LoadTile` task + sync `SyncRemeshTile`): [ClassifyTile (T1.d) + exact validation, only when `voxel.OuterClassifierMode=1`; **default 0 since 2026-09-13**] → `GenerateMesh`/`GenerateSheetMesh` → `BuildTileStreamSet`; records vertex count and resident stream allocation bytes for the horizon trace. Reads Generator/Mesher only → safe on a worker or the game thread; fills `FChunkResult`, no enqueue. |
 | `RecordTileHash` / `WriteTileHashDump` | — | Headless `-voxel.TileHashDump=<absolute path>` parity instrument. Records the exact `FVoxelMeshData` used by the streaming result, including empty/classified tiles, then writes sorted absolute tile keys, LOD step/cells, content-band limits, settings digest context, and the shared `VoxelGeometryHash` at `EndPlay`. |
 | `SyncRemeshTile` | — | **INSTANT DIG**: level-0 same-frame re-mesh on the game thread (`GenerateTileResult` + `ApplyTileResult` inline, Cells=CHUNK_SIZE/Step=1 + strate band, no capture). Used for the tile under the brush centre so a carve is visible THIS frame; one full-res gen on the game thread. |
 | `UpdateChunksAroundPosition` | 362 | Builds desired set, cancels pending keys that left it, sorts from the **true pawn position**, submits the occupied/support LOD0 tile and the next tile along the pawn heading as an absolute `BackgroundHigh` prefix, then loads/unloads and handles LOD changes. **Delta cull**: `BuildDesiredTiles` returns the LEAVERS (stamped `DesiredStamped` map, one sweep) — only those + `TransitionHold` are considered per crossing, not every loaded tile. `BuildDesiredTiles` also applies `RenderDistanceChunks`: the outermost shell widens to cover the distance — as level-MaxClipLevel MC tiles, or (F18 `bFarSheetRing`) as a SHEET ring at level MaxClipLevel+span (covered-check vs the MaxClipLevel box; `VF_OuterShell` shared with `IsTileInClipRange` so the cull sees the same horizon), dz pre-clamped to the vertical band. **§9.3 anchors:** also prunes dead `StreamingAnchors` + detects their chunk crossings → rebuilds the desired set when an anchor moves/(un)registers (`bAnchorsMoved`/`bForceDesiredRebuild`), same cadence as player movement. §8.10. |
@@ -98,7 +98,9 @@ namespace
        int32 AllAir = 0;
        int32 AllSolid = 0;
        int32 Mixed = 0;
+        int64 Vertices = 0;
        int64 Triangles = 0;
+        uint64 GeometryBytes = 0;

        for (const FTileSample& Sample : Samples)
        {
@@ -108,7 +110,9 @@ namespace
            if (Sample.Verdict == 0) ++Mixed;
            else if (Sample.Verdict == 1) ++AllSolid;
            else if (Sample.Verdict == 2) ++AllAir;
+            Vertices += Sample.Vertices;
            Triangles += Sample.Triangles;
+            GeometryBytes += Sample.GeometryBytes;
            Request.Add(Sample.RequestToApplySeconds);
            Queue.Add(Sample.QueueWaitSeconds);
            Generation.Add(Sample.GenerationSeconds);
@@ -118,14 +122,16 @@ namespace
        }

        return FString::Printf(
-            TEXT("{\"count\":%d,\"empty\":%d,\"all_air\":%d,\"all_solid\":%d,\"mixed\":%d,\"triangles\":%lld,"
+            TEXT("{\"count\":%d,\"empty\":%d,\"all_air\":%d,\"all_solid\":%d,\"mixed\":%d,\"vertices\":%lld,\"triangles\":%lld,\"geometry_bytes\":%llu,"
                 "\"request_apply_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                 "\"queue_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                 "\"generation_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                 "\"classify_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                 "\"mesh_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s},"
                 "\"apply_s\":{\"p50\":%s,\"p95\":%s,\"max\":%s}}"),
-            Count, Empty, AllAir, AllSolid, Mixed, static_cast<long long>(Triangles),
+            Count, Empty, AllAir, AllSolid, Mixed,
+            static_cast<long long>(Vertices), static_cast<long long>(Triangles),
+            static_cast<unsigned long long>(GeometryBytes),
            *Number(Percentile(Request, 0.50)), *Number(Percentile(Request, 0.95)), *Number(Maximum(Request)),
            *Number(Percentile(Queue, 0.50)), *Number(Percentile(Queue, 0.95)), *Number(Maximum(Queue)),
            *Number(Percentile(Generation, 0.50)), *Number(Percentile(Generation, 0.95)), *Number(Maximum(Generation)),
@@ -260,12 +266,13 @@ void RecordTile(const FTileSample& Sample)
    GState->Samples.Add(Sample);
    ++GState->TileRecordsWritten;
    WriteEventLocked(*GState, TEXT("tile"), FString::Printf(
-        TEXT("\"tile\":[%d,%d,%d],\"level\":%d,\"verdict\":%d,\"proof\":%d,\"empty\":%d,\"triangles\":%d,"
+        TEXT("\"tile\":[%d,%d,%d],\"level\":%d,\"verdict\":%d,\"proof\":%d,\"empty\":%d,\"vertices\":%d,\"triangles\":%d,\"geometry_bytes\":%llu,"
             "\"request_to_apply_s\":%s,\"queue_wait_s\":%s,\"worker_queue_s\":%s,\"result_queue_s\":%s,"
             "\"generation_s\":%s,\"classify_s\":%s,\"mesh_s\":%s,\"stream_s\":%s,\"apply_s\":%s"),
        Sample.TileX, Sample.TileY, Sample.TileZ,
        Sample.Level, Sample.Verdict, Sample.bSealedSolidProof ? 1 : 0,
-        Sample.bEmpty ? 1 : 0, Sample.Triangles,
+        Sample.bEmpty ? 1 : 0, Sample.Vertices, Sample.Triangles,
+        static_cast<unsigned long long>(Sample.GeometryBytes),
        *Number(Sample.RequestToApplySeconds), *Number(Sample.QueueWaitSeconds),
        *Number(Sample.WorkerQueueSeconds), *Number(Sample.ResultQueueSeconds),
        *Number(Sample.GenerationSeconds), *Number(Sample.ClassifySeconds),
@@ -40,6 +40,8 @@
 #include "Kismet/KismetMaterialLibrary.h"
 #include "Engine/VolumeTexture.h"
 #include "Engine/Engine.h"
+#include "Engine/GameViewportClient.h"
+#include "Slate/SceneViewport.h"
 #include "Camera/CameraActor.h"
 #include "VoxelAtmosphereManager.h"
 #include "DrawDebugHelpers.h"
@@ -535,6 +537,7 @@ void AVoxelWorld::RegenerateAllChunks()
    for (auto& Pair : TileComponents) { if (Pair.Value) ReleaseTileComponent(Pair.Value); }
    TileComponents.Empty();
    LoadedTiles.Empty();
+    LoadedTileGeometry.Reset();
    CollisionReadyTiles.Empty();
    CollisionNotRequiredTiles.Empty();
    CollisionSolidTiles.Empty();
@@ -1420,6 +1423,7 @@ void AVoxelWorld::BeginPlay()
    AppliedTileCount = 0;
    AppliedVisibleTileCount = 0;
    AppliedTriangleCount = 0;
+    LoadedTileGeometry.Reset();
    for (int32 LOD = 0; LOD < TrackedClassifierLODCount; ++LOD)
    {
        AppliedVisibleTileCountByLevel[LOD] = 0;
@@ -1536,18 +1540,43 @@ void AVoxelWorld::BeginPlay()
    }

    int32 TestRenderDistanceChunks = 0;
-    if (FParse::Value(FCommandLine::Get(), TEXT("voxel.TestRenderDistanceChunks="),
+    const bool bTestRenderDistance =
+        FParse::Value(FCommandLine::Get(), TEXT("voxel.TestRenderDistanceChunks="),
                      TestRenderDistanceChunks)
-        && TestRenderDistanceChunks > 0)
+        && TestRenderDistanceChunks > 0;
+    int32 TestMaxClipLevel = -1;
+    const bool bTestMaxClipLevel =
+        FParse::Value(FCommandLine::Get(), TEXT("voxel.TestMaxClipLevel="), TestMaxClipLevel);
+    int32 TestFarSheetRing = -1;
+    const bool bTestFarSheetRing =
+        FParse::Value(FCommandLine::Get(), TEXT("voxel.TestFarSheetRing="), TestFarSheetRing);
+    if (bTestRenderDistance || bTestMaxClipLevel || bTestFarSheetRing)
    {
        if (UVoxelSettings* TestSettings = DuplicateObject<UVoxelSettings>(Settings, this))
        {
            const int32 AuthoredRenderDistance = Settings->RenderDistanceChunks;
-            TestSettings->RenderDistanceChunks = TestRenderDistanceChunks;
+            const int32 AuthoredMaxClipLevel = Settings->MaxClipLevel;
+            const bool bAuthoredFarSheetRing = Settings->bFarSheetRing;
+            if (bTestRenderDistance)
+            {
+                TestSettings->RenderDistanceChunks = TestRenderDistanceChunks;
+            }
+            if (bTestMaxClipLevel)
+            {
+                TestSettings->MaxClipLevel = FMath::Clamp(TestMaxClipLevel, 0, 8);
+            }
+            if (bTestFarSheetRing)
+            {
+                TestSettings->bFarSheetRing = TestFarSheetRing != 0;
+            }
            Settings = TestSettings;
            UE_LOG(LogTemp, Display,
-                TEXT("[VoxelForgeTestCeiling] transient_render_distance_chunks=%d authored=%d"),
-                TestRenderDistanceChunks, AuthoredRenderDistance);
+                TEXT("[VoxelForgeHorizonMeasure] transient_settings=1 "
+                     "render_distance_chunks=%d authored=%d max_clip_level=%d authored=%d "
+                     "far_sheet_ring=%d authored=%d"),
+                Settings->RenderDistanceChunks, AuthoredRenderDistance,
+                Settings->MaxClipLevel, AuthoredMaxClipLevel,
+                Settings->bFarSheetRing ? 1 : 0, bAuthoredFarSheetRing ? 1 : 0);
        }
    }

@@ -1801,6 +1830,7 @@ void AVoxelWorld::BeginPlay()
 void AVoxelWorld::ConfigureHeadlessStreamingTest()
 {
    bHeadlessStreamingTestMovement = false;
+    bHeadlessStreamingTestExitOnSteady = false;
    bHeadlessStreamingTestExitRequested = false;
    bStartupTraceThroughCrossing = false;
    bHeadlessStreamingTestCenterOverride = false;
@@ -1917,9 +1947,14 @@ void AVoxelWorld::ConfigureHeadlessStreamingTest()
    float Speed = 800.0f;
    float StartSeconds = 20.0f;
    float ExitSeconds = 0.0f;
+    int32 ExitOnSteadyValue = 0;
    FParse::Value(CommandLine, TEXT("voxel.TestMoveSpeedCmPerSecond="), Speed);
    FParse::Value(CommandLine, TEXT("voxel.TestMoveStartSeconds="), StartSeconds);
    FParse::Value(CommandLine, TEXT("voxel.TestExitSeconds="), ExitSeconds);
+    if (FParse::Value(CommandLine, TEXT("voxel.TestExitOnSteady="), ExitOnSteadyValue))
+    {
+        bHeadlessStreamingTestExitOnSteady = ExitOnSteadyValue != 0;
+    }

    int32 CrossingValue = 0;
    bHeadlessStrateCrossingTest =
@@ -2181,6 +2216,9 @@ void AVoxelWorld::WriteTileHashDump()
        Writer->WriteValue(TEXT("lod_octave_drop"), Settings->LODOctaveDrop);
        Writer->WriteValue(TEXT("full_res_clip_levels"), Settings->FullResClipLevels);
        Writer->WriteValue(TEXT("coarse_tile_cells"), Settings->CoarseTileCells);
+        Writer->WriteValue(TEXT("max_clip_level"), Settings->MaxClipLevel);
+        Writer->WriteValue(TEXT("render_distance_chunks"), Settings->RenderDistanceChunks);
+        Writer->WriteValue(TEXT("far_sheet_ring"), Settings->bFarSheetRing);
        Writer->WriteValue(TEXT("strate_content_cut_min_level"),
            Settings->GetEffectiveStrateContentCutMinLevel());
        Writer->WriteObjectEnd();
@@ -3592,6 +3630,10 @@ void AVoxelWorld::Tick(float DeltaTime)
        TMap<int32, int32> SteadyLevelCounts;
        TMap<int32, FIntVector> SteadyLevelMins;
        TMap<int32, FIntVector> SteadyLevelMaxs;
+        TMap<int32, int32> LoadedLevelCounts;
+        TMap<int32, uint64> LoadedLevelVertices;
+        TMap<int32, uint64> LoadedLevelTriangles;
+        TMap<int32, uint64> LoadedLevelGeometryBytes;
        for (const FVoxelTileKey& Key : DesiredSorted)
        {
            ++SteadyLevelCounts.FindOrAdd(Key.Level);
@@ -3604,6 +3646,16 @@ void AVoxelWorld::Tick(float DeltaTime)
            Max.Y = FMath::Max(Max.Y, Key.Coord.Y);
            Max.Z = FMath::Max(Max.Z, Key.Coord.Z);
        }
+        for (const FVoxelTileKey& Key : LoadedTiles)
+        {
+            ++LoadedLevelCounts.FindOrAdd(Key.Level);
+            if (const FLoadedTileGeometryStats* Geometry = LoadedTileGeometry.Find(Key))
+            {
+                LoadedLevelVertices.FindOrAdd(Key.Level) += Geometry->Vertices;
+                LoadedLevelTriangles.FindOrAdd(Key.Level) += Geometry->Triangles;
+                LoadedLevelGeometryBytes.FindOrAdd(Key.Level) += Geometry->GeometryBytes;
+            }
+        }
        VoxelForgeStartupTrace::RecordEvent(TEXT("steady_state"), FString::Printf(
             TEXT("\"desired_tiles\":%d,\"loaded_tiles\":%d,\"collision_ready_tiles\":%d,"
                  "\"collision_not_required_tiles\":%d,\"pending_collision_cooks\":%d,"
@@ -3635,8 +3687,22 @@ void AVoxelWorld::Tick(float DeltaTime)
                *FString::SanitizeFloat(TileExtentMetres),
                *FString::SanitizeFloat(SpanX), *FString::SanitizeFloat(SpanY), *FString::SanitizeFloat(SpanZ),
                Settings && Level > VF_MaxMarchingCubesLevel(Settings) ? 1 : 0));
+            VoxelForgeStartupTrace::RecordEvent(TEXT("steady_loaded_level"), FString::Printf(
+                TEXT("\"level\":%d,\"tiles\":%d,\"vertices\":%llu,\"triangles\":%llu,\"geometry_bytes\":%llu"),
+                Level, LoadedLevelCounts.FindRef(Level),
+                static_cast<unsigned long long>(LoadedLevelVertices.FindRef(Level)),
+                static_cast<unsigned long long>(LoadedLevelTriangles.FindRef(Level)),
+                static_cast<unsigned long long>(LoadedLevelGeometryBytes.FindRef(Level))));
        }
+        const bool bExitOnSteady = bHeadlessStreamingTestExitOnSteady;
        VoxelForgeStartupTrace::Finish(TEXT("desired_set_satisfied_and_queue_drained"));
+        if (bExitOnSteady && !bHeadlessStreamingTestExitRequested)
+        {
+            bHeadlessStreamingTestExitRequested = true;
+            UE_LOG(LogTemp, Display,
+                TEXT("[VoxelForgeStreamingTest] steady_exit_requested=1"));
+            FPlatformMisc::RequestExit(false, TEXT("VoxelForge steady streaming measurement complete"));
+        }
    }

    // Complete the one-shot diagnostic request only after the player's level-0 centre tile is
@@ -3745,12 +3811,17 @@ void AVoxelWorld::Tick(float DeltaTime)
                >= static_cast<double>(TestCeilingCaptureDelaySeconds))
        {
            bTestCeilingCaptureRequested = true;
-            const bool bExecSucceeded = GEngine
-                && GEngine->Exec(World, TEXT("HighResShot 1"));
+            // UEngine::Exec is not routed through the game viewport in the command-line game
+            // target, so HighResShot returns false there even with a live render viewport. Call
+            // the viewport API directly; it schedules the same one-frame high-res capture.
+            const bool bCaptureAccepted = GEngine
+                && GEngine->GameViewport
+                && GEngine->GameViewport->GetGameViewport()
+                && GEngine->GameViewport->GetGameViewport()->TakeHighResScreenShot();
            UE_LOG(LogTemp, Display,
                TEXT("[VoxelForgeTestCeiling] capture_requested=%d elapsed_s=%.3f "
                     "visible_tiles=%llu triangles=%llu"),
-                bExecSucceeded ? 1 : 0,
+                bCaptureAccepted ? 1 : 0,
                FPlatformTime::Seconds() - TestCeilingViewBeginSeconds,
                static_cast<unsigned long long>(AppliedVisibleTileCount),
                static_cast<unsigned long long>(AppliedTriangleCount));
@@ -4680,6 +4751,7 @@ void AVoxelWorld::HandleTileCollisionCookComplete(
        // A failed/ignored current cook is not a loaded guarantee. Leaving the tile unloaded makes
        // the normal submit loop retry it while the pawn remains gated.
        LoadedTiles.Remove(Tile);
+        LoadedTileGeometry.Remove(Tile);
        bAllChunksLoaded = false;
    }

@@ -4927,7 +4999,9 @@ bool AVoxelWorld::ApplyTileResult(FChunkResult& Result)
                Sample.Verdict = Result.ClassifyVerdict;
                Sample.bSealedSolidProof = Result.bSealedSolidProof;
                Sample.bEmpty = bResultEmpty;
+                Sample.Vertices = Result.NumVertices;
                Sample.Triangles = Result.NumTriangles;
+                Sample.GeometryBytes = Result.GeometryBytes;
                Sample.RequestToApplySeconds = RequestToApply;
                Sample.WorkerQueueSeconds = WorkerQueueSeconds;
                Sample.ResultQueueSeconds = ResultQueueSeconds;
@@ -4992,6 +5066,7 @@ bool AVoxelWorld::ApplyTileResult(FChunkResult& Result)
                FPlatformTime::Cycles64() - EmptyReleaseStartCycles));
        }
        LoadedTiles.Add(Result.Tile);
+        LoadedTileGeometry.Remove(Result.Tile);
        LogTileApplied();
        if (Result.Tile.Level == 0 && Result.bRecordStreamingLatency)
        {
@@ -5014,11 +5089,16 @@ bool AVoxelWorld::ApplyTileResult(FChunkResult& Result)
        CollisionSolidTiles.Remove(Result.Tile);
        PendingCollisionCooks.Remove(Result.Tile);
        LoadedTiles.Remove(Result.Tile);
+        LoadedTileGeometry.Remove(Result.Tile);
        bAllChunksLoaded = false;
        LogTileApplied();
        return false;
    }
    LoadedTiles.Add(Result.Tile);
+    LoadedTileGeometry.Add(Result.Tile, FLoadedTileGeometryStats{
+        static_cast<uint64>(FMath::Max(0, Result.NumVertices)),
+        static_cast<uint64>(FMath::Max(0, Result.NumTriangles)),
+        Result.GeometryBytes});
    LogTileApplied();
    return true;
 }
@@ -6503,6 +6583,12 @@ void AVoxelWorld::GenerateTileResult(const FVoxelTileKey& Tile, const FIntVector
        VoxelDensityProfile::FScopedTimer RuntimeStreamTimer(
            VoxelDensityProfile::EBucket::RuntimeStreamBuilding);
        BuildTileStreamSet(*Result.Streams, MeshData);
+        Result.NumVertices = MeshData.Vertices.Num();
+        Result.GeometryBytes = 0;
+        Result.Streams->ForEach([&](const RealtimeMesh::FRealtimeMeshStream& Stream)
+        {
+            Result.GeometryBytes += static_cast<uint64>(Stream.GetAllocatedSize());
+        });
        StreamSeconds = bMeasureTile ? FPlatformTime::Seconds() - StreamStartSeconds : 0.0;
        if (ShouldAbortWork(ObsoleteFlag))
        {
@@ -6651,6 +6737,7 @@ void AVoxelWorld::UnloadTile(const FVoxelTileKey& Tile)
        TileComponents.Remove(Tile);
    }
    LoadedTiles.Remove(Tile);
+    LoadedTileGeometry.Remove(Tile);
    TransitionHold.Remove(Tile);   // couvre aussi le settled cull (qui ne tient pas la hold à jour)
 }

@@ -148,8 +148,9 @@ public:

 	// Coarsest LOD level. 0 = full-res only (no clipmap). Each level up doubles tile size &
 	// reach at ~constant cost — raise this to see much farther for cheap. (Level L step = 2^L.)
+	// Ship default: level 5, the measured horizon-distance balance at 768 chunks.
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel|Clipmap", meta = (ClampMin = "0", ClampMax = "8"))
-	int32 MaxClipLevel = 4;
+	int32 MaxClipLevel = 5;

 	// How many near levels mesh at FULL resolution (CHUNK_SIZE cells). Levels at or above this
 	// use the cheaper CoarseTileCells → MUCH faster gen for the far field (it's far, so the
@@ -171,9 +172,9 @@ public:
 	// cell must fit inside a strate band — level ≥7 blanks via the too-coarse skip) and buy the
 	// remaining horizon here. Cost: the extra ring is all same-level tiles — tile/draw/gen count
 	// grows with (distance / 2^MaxClipLevel)², so each MaxClipLevel step down quadruples the ring.
-	// 0 = off (natural reach, byte-identical streaming).
+	// Ship default: 768 chunks (about 6.1 km at 8 m/chunk). 0 = off (natural reach).
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel|Clipmap", meta = (ClampMin = "0"))
-	int32 RenderDistanceChunks = 0;
+	int32 RenderDistanceChunks = 768;

 	// F18 — the render-distance ring streams per-surface SHEETS instead of MC tiles: in an open
 	// strate the far field is exactly two heightfields (TerrainZ + sky-cap CeilSurf, both already
@@ -182,10 +183,11 @@ public:
 	// sheet spans 2^FarSheetSpanLevels MC-tile footprints per axis). Non-open strates produce
 	// empty sheets (their far ring was enclosed rock anyway). Carved features (passages, chasms,
 	// spine) don't show at sheet distance. Needs the strate band armed (StrateContentCutMinLevel
-	// active); in the inter-strate gap the sheet ring blanks until you land. Off = the ring stays
-	// MC tiles at level MaxClipLevel (pre-F18 behaviour). Only matters when RenderDistanceChunks > 0.
+	// active); in the inter-strate gap the sheet ring blanks until you land. The ship default is OFF:
+	// the ring stays real MC tiles at level MaxClipLevel (pre-F18 behaviour). Only matters when
+	// RenderDistanceChunks > 0.
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Voxel|Clipmap")
-	bool bFarSheetRing = true;
+	bool bFarSheetRing = false;

 	// Sheet tile size = MaxClipLevel + this many levels (2 → one sheet covers 4×4 MC-tile
 	// footprints → ~16× fewer far components). Sampling density stays that of the MaxClipLevel
@@ -16,7 +16,9 @@ namespace VoxelForgeStartupTrace
        int32 Verdict = -1; // Mixed=0, AllSolid=1, AllAir=2, -1=not classified (sheet/early path)
        bool bSealedSolidProof = false;
        bool bEmpty = true;
+        int32 Vertices = 0;
        int32 Triangles = 0;
+        uint64 GeometryBytes = 0;
        // This is worker-result -> game-thread mesh submission. Collision readiness is a later
        // per-tile RMC completion event recorded separately as collision_ready.
        double RequestToApplySeconds = 0.0;
@@ -109,6 +109,8 @@ struct FChunkResult
    uint64 GenerationEndCycles = 0;
    uint64 ApplyStartCycles = 0;
    int32 ClassifyVerdict = -1; double ClassifySeconds = 0.0; double MeshSeconds = 0.0; double StreamSeconds = 0.0; int32 NumTriangles = 0; int32 NumCeilingTriangles = 0;
+    int32 NumVertices = 0;
+    uint64 GeometryBytes = 0;
    bool bSealedSolidProof = false; // true when the cheap gap/seal proof skipped meshing
    bool bOutOfLayoutAirProof = false; // true when the exact constant-air guard skipped meshing
    // Clean, low-overhead work counters. These are carried with the result so the worker can
@@ -154,6 +156,14 @@ struct FVoxelTileHashDumpRecord
    FString GeometryHash;
 };

+/** Resident CPU geometry payload associated with one currently loaded tile. */
+struct FLoadedTileGeometryStats
+{
+    uint64 Vertices = 0;
+    uint64 Triangles = 0;
+    uint64 GeometryBytes = 0;
+};
+
 UCLASS()
 class VOXELFORGE_API AVoxelWorld : public AActor
 {
@@ -985,6 +995,7 @@ public:
    uint64 AppliedVisibleTileCountByLevel[TrackedClassifierLODCount]{};
    uint64 AppliedTriangleCountByLevel[TrackedClassifierLODCount]{};
    uint64 AppliedBandTileCountByLevel[TrackedClassifierLODCount]{};
+    TMap<FVoxelTileKey, FLoadedTileGeometryStats> LoadedTileGeometry;

    struct FStreamingLatencySample
    {
@@ -998,6 +1009,7 @@ public:
    // Headless validation hook. These are intentionally non-UPROPERTY state and are enabled only
    // by explicit command-line switches; they do not alter ordinary player movement or streaming.
    bool bHeadlessStreamingTestMovement = false;
+    bool bHeadlessStreamingTestExitOnSteady = false;
    bool bHeadlessStreamingTestExitRequested = false;
    bool bStartupTraceThroughCrossing = false;
    bool bHeadlessStreamingTestCenterOverride = false;
@@ -1,6 +1,6 @@
 [CmdletBinding()]
 param(
-    [ValidateSet('canonical', 'owner', 'probe', 'perf', 'tests', 'surface-fall', 'crossing', 'gate-stress', 'parity')]
+    [ValidateSet('canonical', 'owner', 'probe', 'perf', 'tests', 'surface-fall', 'crossing', 'gate-stress', 'parity', 'horizon', 'horizon-render', 'determinism')]
    [string]$Scenario = 'canonical',
    [switch]$Build,
    [ValidateSet('owner', 'default')]
@@ -8,7 +8,12 @@ param(
    [hashtable]$Cvars = @{},
    [string]$TestFilter,
    [string]$Out,
-    [string]$Label
+    [string]$Label,
+    [ValidateRange(0, 8)]
+    [int]$HorizonLevel = 5,
+    [ValidateRange(1, 100000)]
+    [int]$HorizonRenderDistanceChunks = 768,
+    [string]$SharedDDC
 )

 # One guarded entry point for all VoxelForge measurements.  It intentionally keeps the Unreal
@@ -28,7 +33,7 @@ $EngineRoot = 'E:\Program Files\Epic Games\UE_5.7'
 $EditorExe = Join-Path $EngineRoot 'Engine\Binaries\Win64\UnrealEditor-Cmd.exe'
 $UbtDll = Join-Path $EngineRoot 'Engine\Binaries\DotNET\UnrealBuildTool\UnrealBuildTool.dll'
 $LaunchTimeoutSeconds = 1800
-$UnrealPrivateMemoryLimitBytes = 6GB
+$UnrealPrivateMemoryLimitBytes = 8GB
 # The VoxelForge category includes two late, several-minute op-stack sweeps. They remain in
 # the suite; when the serialized aggregate launch reaches this 30-minute guard, validate those
 # named tests with -TestFilter so every test still runs under the standing launch limit.
@@ -44,6 +49,15 @@ $BuildRecord = [ordered]@{ requested = [bool]$Build; status = 'not_requested' }
 $AssetEvidence = @()
 $CommandletMetrics = [ordered]@{}
 $GameMetrics = [ordered]@{}
+$HorizonMetrics = [ordered]@{
+    requested = $Scenario -in @('horizon', 'horizon-render')
+    status = 'not_run'
+    level = $HorizonLevel
+    render_distance_chunks = $HorizonRenderDistanceChunks
+    far_sheet_ring = $false
+}
+$HorizonRenderMetrics = [ordered]@{ requested = $Scenario -eq 'horizon-render'; status = 'not_run' }
+$DeterminismEvidence = [ordered]@{ requested = $Scenario -eq 'determinism'; status = 'not_run' }
 $SurfaceFallMetrics = [ordered]@{
    requested = $Scenario -eq 'surface-fall' -or
        ($Scenario -eq 'tests' -and [string]::IsNullOrWhiteSpace($TestFilter))
@@ -66,6 +80,7 @@ $LocalAppDataRoot = Join-Path ([Environment]::GetFolderPath('LocalApplicationDat
 $RunRoot = $null
 $ResultPath = $null
 $SummaryPath = $null
+$DDCPath = $null

 function Add-Failure([string]$Reason) {
    if ([string]::IsNullOrWhiteSpace($Reason)) { return }
@@ -485,7 +500,7 @@ function Sync-OwnerAssets {
        $null = Copy-Item -LiteralPath $source -Destination $target -Force -PassThru
        [void]$rows.Add([ordered]@{
            name = $assetName
-            used_by_scenario = $Scenario -in @('owner', 'probe', 'parity', 'tests', 'surface-fall', 'crossing', 'gate-stress')
+            used_by_scenario = $Scenario -in @('owner', 'probe', 'parity', 'tests', 'surface-fall', 'crossing', 'gate-stress', 'horizon', 'horizon-render', 'determinism')
            source_path = $source
            source_sha256 = Get-Sha256 $source
            staged_path = $target
@@ -533,7 +548,7 @@ function Get-AssetEvidence {
        $target = Join-Path $HostRoot "Content\VoxelForge\$assetName.uasset"
        [void]$rows.Add([ordered]@{
            name = $assetName
-            used_by_scenario = $Scenario -in @('owner', 'probe', 'parity', 'tests', 'surface-fall', 'crossing', 'gate-stress')
+            used_by_scenario = $Scenario -in @('owner', 'probe', 'parity', 'tests', 'surface-fall', 'crossing', 'gate-stress', 'horizon', 'horizon-render', 'determinism')
            source_path = $source
            source_sha256 = Get-Sha256 $source
            staged_path = $target
@@ -558,13 +573,19 @@ function Merge-Cvars([System.Collections.IDictionary]$Base) {
    return $merged
 }

-function New-CommonArguments([string]$Kind, [string]$LogPath, $CvarMap) {
+function New-CommonArguments([string]$Kind, [string]$LogPath, $CvarMap, [bool]$EnableRender = $false) {
    $safeLabel = ($Label -replace '[^A-Za-z0-9_.-]', '_')
    $args = [System.Collections.Generic.List[string]]::new()
    # Quoting the whole -project= token is intentional: this is the failure mode that used to
    # swallow every argument after "Projet Unreal".
    [void]$args.Add(('-project="{0}"' -f $HostProject))
-    [void]$args.Add('-nullrhi')
+    if ($EnableRender) {
+        [void]$args.Add('-RenderOffscreen')
+        [void]$args.Add('-ResX=1280')
+        [void]$args.Add('-ResY=720')
+    } else {
+        [void]$args.Add('-nullrhi')
+    }
    [void]$args.Add('-DDC-ForceMemoryCache')
    [void]$args.Add('-unattended')
    [void]$args.Add('-nop4')
@@ -580,7 +601,7 @@ function New-CommonArguments([string]$Kind, [string]$LogPath, $CvarMap) {
    [void]$args.Add(('-userdir="{0}"' -f (Join-Path $RunRoot 'User')))
    [void]$args.Add(('-ZenDataPath="{0}"' -f (Join-Path $RunRoot 'ZenData')))
    [void]$args.Add('-ddc=NoZenLocalFallback')
-    [void]$args.Add(('-LocalDataCachePath="{0}"' -f (Join-Path $RunRoot 'DDC')))
+    [void]$args.Add(('-LocalDataCachePath="{0}"' -f $DDCPath))
    [void]$args.Add(('-abslog="{0}"' -f $LogPath))
    if ($Kind -eq 'commandlet') {
        [void]$args.Add('-run=VoxelForgeExplore')
@@ -720,6 +741,212 @@ function Get-StreamingMetrics([string]$LogPath) {
    return $metrics
 }

+function Get-HorizonMetrics([string]$TracePath, $Ledger, $LatencyMetrics) {
+    $metrics = [ordered]@{
+        status = 'missing'
+        trace = $TracePath
+        desired_tiles_by_level = [ordered]@{}
+        loaded_tiles_by_level = [ordered]@{}
+        vertices_by_level = [ordered]@{}
+        triangles_by_level = [ordered]@{}
+        geometry_memory_bytes_by_level = [ordered]@{}
+        geometry_memory_mib_by_level = [ordered]@{}
+        desired_tiles_total = 0
+        loaded_tiles_total = 0
+        vertices_total = 0
+        triangles_total = 0
+        geometry_memory_bytes_total = 0
+        geometry_memory_mib_total = 0.0
+        worker_generation_seconds = if ($null -ne $LatencyMetrics) {
+            Get-JsonValue $LatencyMetrics 'worker_generation_sum_s' $null
+        } else { $null }
+        settled_trace_seconds = $null
+        trace_summary_wall_seconds = $null
+        process_wall_seconds = $null
+        peak_private_bytes = if ($null -ne $Ledger) {
+            [int64](Get-JsonValue $Ledger 'peak_private_bytes' 0)
+        } else { 0L }
+        peak_private_gib = 0.0
+        trace_records_seen = $null
+        trace_records_written = $null
+        trace_records_suppressed = $null
+    }
+    $metrics.peak_private_gib = [Math]::Round($metrics.peak_private_bytes / 1GB, 3)
+
+    if (-not (Test-Path -LiteralPath $TracePath -PathType Leaf)) { return $metrics }
+    $events = [System.Collections.Generic.List[object]]::new()
+    foreach ($line in @(Get-Content -LiteralPath $TracePath -ErrorAction SilentlyContinue)) {
+        if ([string]::IsNullOrWhiteSpace($line)) { continue }
+        try { [void]$events.Add(($line | ConvertFrom-Json -ErrorAction Stop)) } catch { }
+    }
+    $steady = @($events | Where-Object { [string](Get-JsonValue $_ 'type' '') -eq 'steady_state' } | Select-Object -Last 1)
+    $summary = @($events | Where-Object { [string](Get-JsonValue $_ 'type' '') -eq 'summary' } | Select-Object -Last 1)
+    $desiredEvents = @($events | Where-Object { [string](Get-JsonValue $_ 'type' '') -eq 'steady_desired_level' })
+    $loadedEvents = @($events | Where-Object { [string](Get-JsonValue $_ 'type' '') -eq 'steady_loaded_level' })
+    if ($steady.Count -eq 0 -or $summary.Count -eq 0 -or $desiredEvents.Count -eq 0) {
+        return $metrics
+    }
+
+    foreach ($event in $desiredEvents) {
+        $level = [string][int](Get-JsonValue $event 'level' -1)
+        $metrics.desired_tiles_by_level[$level] = [int](Get-JsonValue $event 'tiles' 0)
+    }
+    foreach ($event in $loadedEvents) {
+        $level = [string][int](Get-JsonValue $event 'level' -1)
+        $metrics.loaded_tiles_by_level[$level] = [int](Get-JsonValue $event 'tiles' 0)
+        $metrics.vertices_by_level[$level] = [int64](Get-JsonValue $event 'vertices' 0)
+        $metrics.triangles_by_level[$level] = [int64](Get-JsonValue $event 'triangles' 0)
+        $bytes = [int64](Get-JsonValue $event 'geometry_bytes' 0)
+        $metrics.geometry_memory_bytes_by_level[$level] = $bytes
+        $metrics.geometry_memory_mib_by_level[$level] = [Math]::Round($bytes / 1MB, 3)
+    }
+    foreach ($value in $metrics.desired_tiles_by_level.Values) { $metrics.desired_tiles_total += [int64]$value }
+    foreach ($value in $metrics.loaded_tiles_by_level.Values) { $metrics.loaded_tiles_total += [int64]$value }
+    foreach ($value in $metrics.vertices_by_level.Values) { $metrics.vertices_total += [int64]$value }
+    foreach ($value in $metrics.triangles_by_level.Values) { $metrics.triangles_total += [int64]$value }
+    foreach ($value in $metrics.geometry_memory_bytes_by_level.Values) { $metrics.geometry_memory_bytes_total += [int64]$value }
+    $metrics.geometry_memory_mib_total = [Math]::Round($metrics.geometry_memory_bytes_total / 1MB, 3)
+    $metrics.settled_trace_seconds = [double](Get-JsonValue $steady[0] 't_s' 0.0)
+    $metrics.trace_summary_wall_seconds = [double](Get-JsonValue $summary[0] 'wall_s' 0.0)
+    $metrics.trace_records_seen = [int](Get-JsonValue $summary[0] 'tile_records_seen' 0)
+    $metrics.trace_records_written = [int](Get-JsonValue $summary[0] 'tile_records_written' 0)
+    $metrics.trace_records_suppressed = [int](Get-JsonValue $summary[0] 'tile_records_suppressed' 0)
+    if ($null -ne $Ledger) {
+        $started = [datetime]::Parse([string](Get-JsonValue $Ledger 'started_utc' ''))
+        $ended = [datetime]::Parse([string](Get-JsonValue $Ledger 'ended_utc' ''))
+        $metrics.process_wall_seconds = [Math]::Round(($ended.ToUniversalTime() - $started.ToUniversalTime()).TotalSeconds, 3)
+    }
+    $metrics.status = 'ok'
+    return $metrics
+}
+
+function Get-HorizonRenderMetrics($Ledger, [string]$LogPath) {
+    $metrics = [ordered]@{
+        status = 'failed'
+        log = $LogPath
+        capture_requested = $null
+        capture_elapsed_seconds = $null
+        capture_visible_tiles = $null
+        capture_triangles = $null
+        images = @()
+    }
+    $lines = @(Select-String -LiteralPath $LogPath -Pattern '\[VoxelForgeTestCeiling\] capture_requested=' -ErrorAction SilentlyContinue)
+    if ($lines.Count -gt 0) {
+        $line = [string]$lines[-1].Line
+        $metrics.raw = $line
+        foreach ($key in @('capture_requested', 'elapsed_s', 'visible_tiles', 'triangles')) {
+            $match = [regex]::Match($line, ('{0}=(?<v>[^ ]+)' -f $key))
+            if ($match.Success) {
+                if ($key -eq 'elapsed_s') { $metrics.capture_elapsed_seconds = [double]$match.Groups['v'].Value }
+                elseif ($key -eq 'visible_tiles') { $metrics.capture_visible_tiles = [int64]$match.Groups['v'].Value }
+                elseif ($key -eq 'triangles') { $metrics.capture_triangles = [int64]$match.Groups['v'].Value }
+                else { $metrics.capture_requested = [int]$match.Groups['v'].Value }
+            }
+        }
+    }
+    $started = if ($null -ne $Ledger) {
+        [datetime]::Parse([string](Get-JsonValue $Ledger 'started_utc' ''))
+    } else { [datetime]::MinValue }
+    $roots = @(
+        (Join-Path $HostRoot 'Saved'),
+        $RunRoot,
+        (Join-Path $RunRoot 'User'))
+    $images = [System.Collections.Generic.List[object]]::new()
+    foreach ($root in $roots) {
+        if (-not (Test-Path -LiteralPath $root -PathType Container)) { continue }
+        foreach ($image in @(Get-ChildItem -LiteralPath $root -Filter '*.png' -File -Recurse -ErrorAction SilentlyContinue)) {
+            if ($image.LastWriteTimeUtc -lt $started.ToUniversalTime().AddSeconds(-2)) { continue }
+            [void]$images.Add([ordered]@{
+                path = $image.FullName
+                bytes = [int64]$image.Length
+                modified_utc = $image.LastWriteTimeUtc.ToString('o')
+            })
+        }
+    }
+    $metrics.images = @($images | Sort-Object path -Unique)
+    if ($metrics.capture_requested -eq 1 -and $metrics.images.Count -gt 0) {
+        $metrics.status = 'passed'
+    } elseif ($null -eq $Ledger -or (Get-JsonValue $Ledger 'status' 'failed') -ne 'passed') {
+        $metrics.status = 'not_run'
+    }
+    return $metrics
+}
+
+function Compare-DeterminismDumps([string]$DefaultPath, [string]$CrtFma3OffPath) {
+    $defaultJson = Read-JsonFile $DefaultPath
+    $fmaJson = Read-JsonFile $CrtFma3OffPath
+    $evidence = [ordered]@{
+        status = 'failed'
+        default_dump = $DefaultPath
+        crt_fma3_off_dump = $CrtFma3OffPath
+        default_record_count = 0
+        crt_fma3_off_record_count = 0
+        compared_tile_count = 0
+        first_differences = @()
+    }
+    if ($null -eq $defaultJson -or $null -eq $fmaJson) {
+        $evidence.reason = 'one or both tile hash dumps are missing'
+        return $evidence
+    }
+    $defaultRecords = @((Get-JsonValue $defaultJson 'records' @()))
+    $fmaRecords = @((Get-JsonValue $fmaJson 'records' @()))
+    $evidence.default_record_count = $defaultRecords.Count
+    $evidence.crt_fma3_off_record_count = $fmaRecords.Count
+    $defaultByKey = @{}
+    $fmaByKey = @{}
+    foreach ($record in $defaultRecords) {
+        $key = "$($record.tile_x):$($record.tile_y):$($record.tile_z):$($record.level)"
+        $defaultByKey[$key] = $record
+    }
+    foreach ($record in $fmaRecords) {
+        $key = "$($record.tile_x):$($record.tile_y):$($record.tile_z):$($record.level)"
+        $fmaByKey[$key] = $record
+    }
+    $differences = [System.Collections.Generic.List[object]]::new()
+    $keys = @($defaultByKey.Keys) + @($fmaByKey.Keys) | Sort-Object -Unique
+    foreach ($key in $keys) {
+        if (-not $defaultByKey.ContainsKey($key)) {
+            [void]$differences.Add([ordered]@{ tile = $key; reason = 'missing_from_default' })
+            continue
+        }
+        if (-not $fmaByKey.ContainsKey($key)) {
+            [void]$differences.Add([ordered]@{ tile = $key; reason = 'missing_from_crt_fma3_off' })
+            continue
+        }
+        $left = $defaultByKey[$key]
+        $right = $fmaByKey[$key]
+        foreach ($property in @('origin_x_voxels', 'origin_y_voxels', 'origin_z_voxels',
+                                'step', 'cells', 'band_chunk_lo', 'band_chunk_hi',
+                                'sheet_tile', 'empty', 'triangle_count', 'geometry_hash')) {
+            if ([string](Get-JsonValue $left $property '') -ne [string](Get-JsonValue $right $property '')) {
+                [void]$differences.Add([ordered]@{
+                    tile = $key
+                    reason = "property_mismatch:$property"
+                    default = Get-JsonValue $left $property $null
+                    crt_fma3_off = Get-JsonValue $right $property $null
+                })
+                break
+            }
+        }
+    }
+    $evidence.compared_tile_count = [Math]::Min($defaultByKey.Count, $fmaByKey.Count)
+    $evidence.first_differences = @($differences | Select-Object -First 10)
+    $leftConfig = Get-JsonValue $defaultJson 'runtime_config' $null
+    $rightConfig = Get-JsonValue $fmaJson 'runtime_config' $null
+    $evidence.runtime_config_match = (ConvertTo-CompactJson $leftConfig) -eq (ConvertTo-CompactJson $rightConfig)
+    $evidence.default_runtime_config = $leftConfig
+    $evidence.crt_fma3_off_runtime_config = $rightConfig
+    if ($differences.Count -eq 0 -and $evidence.runtime_config_match -and
+        $defaultByKey.Count -eq $fmaByKey.Count) {
+        $evidence.status = 'passed'
+    } else {
+        $evidence.reason = if ($differences.Count -gt 0) { 'per-tile geometry differs' }
+            elseif (-not $evidence.runtime_config_match) { 'runtime configuration differs' }
+            else { 'tile record counts differ' }
+    }
+    return $evidence
+}
+
 function Get-SurfaceFallMetrics([string]$LogPath) {
    $lineMatch = @(Select-String -LiteralPath $LogPath -Pattern '\[VoxelForgeSurfaceFallTest\] result=' -ErrorAction SilentlyContinue |
        Select-Object -Last 1)
@@ -926,7 +1153,17 @@ try {
    Ensure-Directory (Join-Path $RunRoot 'Logs')
    Ensure-Directory (Join-Path $RunRoot 'User')
    Ensure-Directory (Join-Path $RunRoot 'ZenData')
-    Ensure-Directory (Join-Path $RunRoot 'DDC')
+    $DDCPath = Join-Path $RunRoot 'DDC'
+    if (-not [string]::IsNullOrWhiteSpace($SharedDDC)) {
+        if (-not [IO.Path]::IsPathRooted($SharedDDC)) {
+            throw "-SharedDDC must be an absolute path: $SharedDDC"
+        }
+        $DDCPath = Get-FullPath $SharedDDC
+        if (-not (Test-UnderPath $DDCPath (Join-Path $PluginRoot 'Saved'))) {
+            throw "-SharedDDC must stay under the plugin Saved directory: $DDCPath"
+        }
+    }
+    Ensure-Directory $DDCPath
    $localBefore = Get-StateSnapshot $LocalAppDataRoot

    foreach ($required in @($EditorExe, $UbtDll, $HostProject, $ProjectFile)) {
@@ -944,7 +1181,7 @@ try {
        $buildStdout = Join-Path $RunRoot 'Logs\build.stdout.log'
        $buildError = Join-Path $RunRoot 'Logs\build.err.log'
        $buildArgs = @(('"{0}"' -f $UbtDll), 'UnrealEditor', 'Win64', 'Development', ('-Project="{0}"' -f $HostProject),
-            '-WaitMutex', '-FromMsBuild', '-architecture=x64', '-NoUBA', '-MaxParallelActions=2',
+            '-WaitMutex', '-FromMsBuild', '-architecture=x64', '-NoUBA', '-MaxParallelActions=4',
            ('-Log="{0}"' -f $buildLog))
        $BuildRecord = Invoke-BuildProcess $buildArgs $buildLog $buildError $buildStdout
        if ($BuildRecord.status -ne 'passed') { Add-Failure "staged build $($BuildRecord.status)" }
@@ -1017,6 +1254,94 @@ try {
                (Join-Path $RunRoot 'Logs\probe.log') (Join-Path $RunRoot 'Logs\probe.stdout.log') (Join-Path $RunRoot 'Logs\probe.stderr.log')
            $CommandletMetrics = Get-CommandletMetrics $commandletOut 'owner probe'
        }
+        'horizon' {
+            $tracePath = Join-Path $RunRoot 'horizon_trace.jsonl'
+            $baseCvars['voxel.TestRenderDistanceChunks'] = $HorizonRenderDistanceChunks
+            $baseCvars['voxel.TestMaxClipLevel'] = $HorizonLevel
+            $baseCvars['voxel.TestFarSheetRing'] = 0
+            $baseCvars['voxel.StartupTraceFile'] = $tracePath
+            $baseCvars['voxel.StartupTraceMaxTiles'] = 16384
+            $baseCvars['voxel.TestExitOnSteady'] = 1
+            $baseCvars['voxel.OuterClassifierMode'] = 0
+            $args = New-CommonArguments 'game' (Join-Path $RunRoot 'Logs\horizon.log') (Merge-Cvars $baseCvars)
+            $gameLedger = Invoke-UnrealLaunch "horizon-l$($HorizonLevel)-$($HorizonRenderDistanceChunks)-game" $args `
+                (Join-Path $RunRoot 'Logs\horizon.log') (Join-Path $RunRoot 'Logs\horizon.stdout.log') (Join-Path $RunRoot 'Logs\horizon.stderr.log')
+            $GameMetrics = Get-StreamingMetrics (Join-Path $RunRoot 'Logs\horizon.log')
+            $HorizonMetrics = Get-HorizonMetrics $tracePath $gameLedger $GameMetrics
+            if ($HorizonMetrics.status -ne 'ok') {
+                Add-Failure "horizon measurement trace did not settle: $($HorizonMetrics.status)"
+            }
+        }
+        'horizon-render' {
+            $tracePath = Join-Path $RunRoot 'horizon_render_trace.jsonl'
+            $baseCvars['voxel.TestRenderDistanceChunks'] = $HorizonRenderDistanceChunks
+            $baseCvars['voxel.TestMaxClipLevel'] = $HorizonLevel
+            $baseCvars['voxel.TestFarSheetRing'] = 0
+            $baseCvars['voxel.StartupTraceFile'] = $tracePath
+            $baseCvars['voxel.StartupTraceMaxTiles'] = 16384
+            $baseCvars['voxel.TestCeilingView'] = 1
+            $baseCvars['voxel.TestCeilingCaptureDelaySeconds'] = 90
+            $baseCvars['voxel.TestExitSeconds'] = 180
+            $baseCvars['voxel.OuterClassifierMode'] = 0
+            $renderLog = Join-Path $RunRoot 'Logs\horizon-render.log'
+            $args = New-CommonArguments 'game' $renderLog (Merge-Cvars $baseCvars) $true
+            $gameLedger = Invoke-UnrealLaunch "horizon-l$($HorizonLevel)-$($HorizonRenderDistanceChunks)-render" $args `
+                $renderLog (Join-Path $RunRoot 'Logs\horizon-render.stdout.log') (Join-Path $RunRoot 'Logs\horizon-render.stderr.log')
+            $GameMetrics = Get-StreamingMetrics $renderLog
+            $HorizonMetrics = Get-HorizonMetrics $tracePath $gameLedger $GameMetrics
+            $HorizonRenderMetrics = Get-HorizonRenderMetrics $gameLedger $renderLog
+            if ($HorizonMetrics.status -ne 'ok') {
+                Add-Failure "horizon render trace did not settle: $($HorizonMetrics.status)"
+            }
+            if ($HorizonRenderMetrics.status -ne 'passed') {
+                Add-Failure "horizon render did not produce a capture: $($HorizonRenderMetrics.status)"
+            }
+        }
+        'determinism' {
+            $defaultDump = Join-Path $RunRoot 'tile_hashes_default.json'
+            $crtFma3OffDump = Join-Path $RunRoot 'tile_hashes_crt_fma3_off.json'
+            $defaultTrace = Join-Path $RunRoot 'determinism_default_trace.jsonl'
+            $crtFma3OffTrace = Join-Path $RunRoot 'determinism_crt_fma3_off_trace.jsonl'
+            $determinismBase = [ordered]@{
+                'voxel.TestRenderDistanceChunks' = $HorizonRenderDistanceChunks
+                'voxel.TestMaxClipLevel' = $HorizonLevel
+                'voxel.TestFarSheetRing' = 0
+                'voxel.TestExitOnSteady' = 1
+                'voxel.StartupTraceMaxTiles' = 16384
+                'voxel.OuterClassifierMode' = 0
+            }
+            $defaultCvars = [ordered]@{}
+            foreach ($key in $determinismBase.Keys) { $defaultCvars[$key] = $determinismBase[$key] }
+            $defaultCvars['voxel.StartupTraceFile'] = $defaultTrace
+            $defaultCvars['voxel.TileHashDump'] = $defaultDump
+            $defaultLog = Join-Path $RunRoot 'Logs\determinism-default.log'
+            $defaultArgs = New-CommonArguments 'game' $defaultLog (Merge-Cvars $defaultCvars)
+            $defaultLedger = Invoke-UnrealLaunch "determinism-default-l$($HorizonLevel)-$($HorizonRenderDistanceChunks)" $defaultArgs `
+                $defaultLog (Join-Path $RunRoot 'Logs\determinism-default.stdout.log') (Join-Path $RunRoot 'Logs\determinism-default.stderr.log')
+            $defaultMetrics = Get-HorizonMetrics $defaultTrace $defaultLedger (Get-StreamingMetrics $defaultLog)
+
+            $crtFma3OffCvars = [ordered]@{}
+            foreach ($key in $determinismBase.Keys) { $crtFma3OffCvars[$key] = $determinismBase[$key] }
+            $crtFma3OffCvars['voxel.StartupTraceFile'] = $crtFma3OffTrace
+            $crtFma3OffCvars['voxel.TileHashDump'] = $crtFma3OffDump
+            $crtFma3OffCvars['voxel.CrtFma3'] = 0
+            $crtFma3OffLog = Join-Path $RunRoot 'Logs\determinism-crt-fma3-off.log'
+            $crtFma3OffArgs = New-CommonArguments 'game' $crtFma3OffLog (Merge-Cvars $crtFma3OffCvars)
+            $crtFma3OffLedger = Invoke-UnrealLaunch "determinism-crt-fma3-off-l$($HorizonLevel)-$($HorizonRenderDistanceChunks)" $crtFma3OffArgs `
+                $crtFma3OffLog (Join-Path $RunRoot 'Logs\determinism-crt-fma3-off.stdout.log') (Join-Path $RunRoot 'Logs\determinism-crt-fma3-off.stderr.log')
+            $crtFma3OffMetrics = Get-HorizonMetrics $crtFma3OffTrace $crtFma3OffLedger (Get-StreamingMetrics $crtFma3OffLog)
+
+            $DeterminismEvidence = Compare-DeterminismDumps $defaultDump $crtFma3OffDump
+            $DeterminismEvidence.level = $HorizonLevel
+            $DeterminismEvidence.render_distance_chunks = $HorizonRenderDistanceChunks
+            $DeterminismEvidence.far_sheet_ring = $false
+            $DeterminismEvidence.default_measurement = $defaultMetrics
+            $DeterminismEvidence.crt_fma3_off_measurement = $crtFma3OffMetrics
+            $GameMetrics = $crtFma3OffMetrics
+            if ($DeterminismEvidence.status -ne 'passed') {
+                Add-Failure "determinism comparison failed: $(Get-JsonValue $DeterminismEvidence 'reason' 'unknown difference')"
+            }
+        }
        'perf' {
            $baseCvars['voxel.TestExitSeconds'] = 15
            $baseCvars['voxel.ProfileTileGeneration'] = 1
@@ -1201,6 +1526,7 @@ $result = [ordered]@{
    scenario = $Scenario
    label = $Label
    run_directory = $RunRoot
+    ddc_path = $DDCPath
    project = $ProjectFile
    staged_host = $HostProject
    assets_mode = $Assets
@@ -1220,6 +1546,9 @@ $result = [ordered]@{
    probe_amplitudes = if ($CommandletMetrics.Contains('probe_amplitudes')) { $CommandletMetrics.probe_amplitudes } else { [ordered]@{} }
    commandlet = $CommandletMetrics
    game = $GameMetrics
+    horizon = $HorizonMetrics
+    horizon_render = $HorizonRenderMetrics
+    determinism = $DeterminismEvidence
    surface_fall = $SurfaceFallMetrics
    strate_crossing = $StrateCrossingMetrics
    collision_gate_stress = $CollisionGateStressMetrics
@@ -1246,6 +1575,7 @@ try {
    [void]$summaryLines.Add("$(if ($pass) { 'PASS' } else { 'FAIL' }) $reason")
    [void]$summaryLines.Add("scenario=$Scenario label=$Label")
    [void]$summaryLines.Add("run_directory=$RunRoot")
+    [void]$summaryLines.Add("ddc_path=$DDCPath")
    [void]$summaryLines.Add("assets=$Assets")
    [void]$summaryLines.Add("canonical_baseline=$(ConvertTo-CompactJson $result.canonical_baseline)")
    [void]$summaryLines.Add("capability_counts=$(ConvertTo-CompactJson $result.capability_counts)")
@@ -1257,6 +1587,9 @@ try {
    [void]$summaryLines.Add("collision_gate_stress=$(ConvertTo-CompactJson $result.collision_gate_stress)")
    [void]$summaryLines.Add("probe_amplitudes=$(ConvertTo-CompactJson $result.probe_amplitudes)")
    [void]$summaryLines.Add("worker_seconds=$(ConvertTo-CompactJson $result.worker_seconds)")
+    [void]$summaryLines.Add("horizon=$(ConvertTo-CompactJson $result.horizon)")
+    [void]$summaryLines.Add("horizon_render=$(ConvertTo-CompactJson $result.horizon_render)")
+    [void]$summaryLines.Add("determinism=$(ConvertTo-CompactJson $result.determinism)")
    [void]$summaryLines.Add("p50_p95=$(ConvertTo-CompactJson $result.p50_p95)")
    [void]$summaryLines.Add("tests=$(ConvertTo-CompactJson $result.tests)")
    [void]$summaryLines.Add("parity=$(ConvertTo-CompactJson $result.parity)")