diff --git a/RENDER.md b/RENDER.md
index ad4b608..e57fe40 100644
--- a/RENDER.md
+++ b/RENDER.md
@@ -1478,6 +1478,19 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
   1,000 simple group attachments. This extraction adds no asset-backed GPU,
   leak, p95/p99 or original-client visual-fidelity evidence.
 
+## 2026-08-01 WMO Runtime Scene Preparer Extraction
+
+- `WmoRuntimeScenePreparer` now owns cached WMO parent-before-children Mesh/
+  MultiMesh finalization and the shared cached/live render-policy preparation.
+- The historical path distinction is unchanged: live-built duplicates do not
+  cross the cached runtime Mesh finalizer boundary.
+- Disabled occlusion still removes only the direct child named `Occluders`;
+  enabled shadows still set descendant GeometryInstance3D nodes ON, while the
+  disabled shadow branch preserves existing values.
+- Instantiation, placement, attachment, registry lifetime, Editor ownership,
+  queues and permits remain loader-owned. Synthetic traversal timing is not
+  private-asset visual, leak, GPU or p95/p99 evidence.
+
 ## Practical Rule For Future Work
 
 If something improves quality but creates visible hitch, it is not done. Move it to bake/cache/background work, split finalization over frames, or prewarm it before the player can see it.
diff --git a/docs/modules/README.md b/docs/modules/README.md
index 7b09af8..918a793 100644
--- a/docs/modules/README.md
+++ b/docs/modules/README.md
@@ -51,6 +51,7 @@
 | WMO scene Resource finalizer | Implemented extraction | [`wmo-scene-resource-finalizer.md`](wmo-scene-resource-finalizer.md) |
 | WMO runtime Mesh finalizer | Implemented extraction | [`wmo-runtime-mesh-finalizer.md`](wmo-runtime-mesh-finalizer.md) |
 | WMO render group materializer | Implemented extraction | [`wmo-render-group-materializer.md`](wmo-render-group-materializer.md) |
+| WMO runtime scene preparer | Implemented extraction | [`wmo-runtime-scene-preparer.md`](wmo-runtime-scene-preparer.md) |
 | Third-person camera | Implemented | [`third-person-camera.md`](third-person-camera.md) |
 | Character presentation | Implemented boundary / Partial fidelity | [`character-presentation.md`](character-presentation.md) |
 | Renderer | Partial | [`world-renderer.md`](world-renderer.md), [`../../RENDER.md`](../../RENDER.md) |
diff --git a/docs/modules/wmo-runtime-mesh-finalizer.md b/docs/modules/wmo-runtime-mesh-finalizer.md
index 667b389..54c82ca 100644
--- a/docs/modules/wmo-runtime-mesh-finalizer.md
+++ b/docs/modules/wmo-runtime-mesh-finalizer.md
@@ -27,14 +27,17 @@ refresh version and reconstruct eligible surface materials through WMOBuilder.
 
 ```mermaid
 flowchart LR
-    Loader[StreamingWorldLoader traversal/build step] -->|Mesh plus extracted directory| Finalizer[WmoRuntimeMeshFinalizer]
+    Loader[StreamingWorldLoader render build step] -->|Mesh plus extracted directory| Finalizer[WmoRuntimeMeshFinalizer]
+    Preparer[WmoRuntimeScenePreparer cached traversal] -->|Mesh plus extracted directory| Finalizer
     Finalizer -->|material definition plus compact texture paths| Builder[WMOBuilder material boundary]
     Builder -->|rebuilt Material| Finalizer
     Finalizer -->|same Mesh identity| Loader
+    Finalizer -->|same Mesh identity| Preparer
 ```
 
-The loader owns scene traversal and composition. The finalizer owns only the
-in-place Resource operation and depends on an injected WMO material builder.
+The runtime scene preparer owns cached-scene traversal; the loader owns render
+build-step selection and composition. The finalizer owns only the in-place
+Resource operation and depends on an injected WMO material builder.
 
 ## Public API
 
@@ -52,7 +55,7 @@ in-place Resource operation and depends on an injected WMO material builder.
 | Input | Texture paths, WMO flags/shader/blend and cached colors | Surface Material metadata/parameters | Finalizer | Borrowed values | One surface rebuild |
 | Output | Compact texture-path array and material definition | Finalizer | WMOBuilder | Detached values | One builder call |
 | Output | Rebuilt Material | WMOBuilder | ArrayMesh surface | Surface adopts exact Resource | Mesh lifetime |
-| Output | Exact input Mesh | Finalizer | Loader traversal/build step | Caller retains ownership | Existing cache/scene lifetime |
+| Output | Exact input Mesh | Finalizer | Runtime scene preparer or loader build step | Caller retains ownership | Existing cache/scene lifetime |
 
 ## Data flow
 
@@ -96,10 +99,15 @@ in the extracted loader behavior. The finalizer retains no Mesh or Material.
 ```mermaid
 sequenceDiagram
     participant Loader as StreamingWorldLoader
+    participant Preparer as WmoRuntimeScenePreparer
     participant Finalizer as WmoRuntimeMeshFinalizer
     participant Mesh as ArrayMesh
     participant Builder as WMOBuilder
-    Loader->>Finalizer: finalize_mesh(mesh, extracted_directory)
+    alt lightweight render build step
+        Loader->>Finalizer: finalize_mesh(mesh, extracted_directory)
+    else cached scene traversal
+        Preparer->>Finalizer: finalize_mesh(mesh, extracted_directory)
+    end
     Finalizer->>Mesh: read/stamp refresh metadata
     loop each stale ArrayMesh surface
         Finalizer->>Mesh: surface_get_material(index)
@@ -109,7 +117,8 @@ sequenceDiagram
             Finalizer->>Mesh: surface_set_material when non-null
         end
     end
-    Finalizer-->>Loader: exact Mesh identity
+    Finalizer-->>Loader: exact Mesh identity for build path
+    Finalizer-->>Preparer: exact Mesh identity for cached traversal path
 ```
 
 ## Dependency diagram
@@ -117,6 +126,7 @@ sequenceDiagram
 ```mermaid
 flowchart TB
     Loader[StreamingWorldLoader] --> Finalizer[WmoRuntimeMeshFinalizer]
+    Preparer[WmoRuntimeScenePreparer] --> Finalizer
     Finalizer --> Engine[Mesh / ArrayMesh / Material]
     Finalizer --> Builder[Injected WMO material builder]
     Finalizer -. no dependency .-> Nodes[Node traversal/lifetime]
@@ -184,7 +194,8 @@ metrics and loader diagnostics remain the operational correlation surface.
 |---|---|---|---|
 | Runtime refresh admission | Implemented extraction | Identity/version/type contracts | Serialized cache fixture pending |
 | Cached material definition reconstruction | Implemented extraction | Path/metadata/color contracts | Asset-backed visual comparison pending |
-| Scene traversal/materialization | Loader-owned | Existing WMO regressions | Further safe extraction pending |
+| Scene traversal | Runtime scene preparer-owned | Cached/live traversal regressions | Asset-backed traversal pending |
+| Node materialization | Loader/group-materializer-owned | Existing WMO regressions | Further safe extraction pending |
 
 ## Known gaps and risks
 
@@ -199,7 +210,8 @@ metrics and loader diagnostics remain the operational correlation surface.
 |---|---|
 | `src/render/wmo/wmo_runtime_mesh_finalizer.gd` | Refresh admission, surface iteration and material definition reconstruction |
 | `addons/mpq_extractor/loaders/wmo_builder.gd` | WMO shader/material construction semantics |
-| `src/scenes/streaming/streaming_world_loader.gd` | Composition, Node traversal, build jobs and lifetime |
+| `src/render/wmo/wmo_runtime_scene_preparer.gd` | Cached scene traversal and finalizer delegation |
+| `src/scenes/streaming/streaming_world_loader.gd` | Composition, build jobs, placement and lifetime |
 | `src/tools/verify_wmo_runtime_mesh_finalizer.gd` | Identity/version/material/source/timing regression |
 
 ## Related decisions and references
diff --git a/docs/modules/wmo-runtime-scene-preparer.md b/docs/modules/wmo-runtime-scene-preparer.md
new file mode 100644
index 0000000..2bb8080
--- /dev/null
+++ b/docs/modules/wmo-runtime-scene-preparer.md
@@ -0,0 +1,211 @@
+# WMO Runtime Scene Preparer
+
+## Metadata
+
+| Field | Value |
+|---|---|
+| Status | Implemented |
+| Target | M03 Renderer Facade and Safe Extraction |
+| Work package | `M03-RND-WMO-RUNTIME-SCENE-PREPARER-001` |
+| Owner | Render |
+| Last verified | 2026-08-01 |
+
+## Purpose
+
+`WmoRuntimeScenePreparer` applies the existing post-instantiation rules to a
+borrowed WMO subtree on the renderer main thread. Cached scenes receive recursive
+Mesh finalization before render policy; live-built duplicates receive render
+policy only.
+
+## Non-goals
+
+- load, validate, instantiate, duplicate, place or attach a WMO scene;
+- change `WmoRuntimeMeshFinalizer` material/version rules;
+- own the supplied subtree or decide Editor persistence;
+- change cache formats, queue progress, permits or shutdown;
+- implement portal/room visibility or recursive occluder discovery.
+
+## Context and boundaries
+
+The loader distinguishes validated cached PackedScene instances from duplicated
+live-built prototypes. That distinction remains explicit through two public
+methods so the live path does not gain cached-Mesh refresh behavior.
+
+```mermaid
+flowchart LR
+    Cached[Validated cached WMO instance] --> Loader[StreamingWorldLoader]
+    Live[Duplicated live-built WMO instance] --> Loader
+    Loader -->|prepare_cached_instance| Preparer[WmoRuntimeScenePreparer]
+    Loader -->|prepare_live_instance| Preparer
+    Preparer -->|cached only| MeshFinalizer[WmoRuntimeMeshFinalizer]
+    Preparer --> Policy[Direct Occluders policy + recursive shadow enabling]
+    Policy --> Borrowed[Borrowed WMO Node3D subtree]
+    Loader --> Placement[Placement/attachment/registry lifecycle]
+```
+
+## Public API
+
+| Symbol | Role | Thread/lifetime | Failure behavior |
+|---|---|---|---|
+| `prepare_cached_instance(instance, extracted_directory, enable_occlusion_culling, cast_shadows)` | Finalize cached subtree Meshes, then apply render policy | Renderer main thread; stateless after return | Null/freed root returns false |
+| `prepare_live_instance(instance, enable_occlusion_culling, cast_shadows)` | Apply render policy without Mesh finalization | Renderer main thread; stateless after return | Null/freed root returns false |
+
+Both methods borrow the root and return a success flag. Disabled occlusion removes
+only the direct child named `Occluders`, matching the previous loader lookup.
+Enabled shadows set all descendant `GeometryInstance3D` nodes to ON. Disabled
+shadows preserve every existing value rather than forcing OFF.
+
+## Inputs and outputs
+
+| Direction | Contract/data | Producer | Consumer | Ownership | Thread/lifetime |
+|---|---|---|---|---|---|
+| Input | Cached or live-built WMO `Node3D` | Loader scene/prototype adapter | Preparer | Borrowed exact subtree | One main-thread call |
+| Input | Extracted directory | Loader configuration | Runtime Mesh finalizer via preparer | Borrowed String | Cached preparation call |
+| Input | Occlusion/shadow policy | Loader quality configuration | Preparer | Scalar values | One call |
+| Internal | Mesh/MultiMesh Mesh reference | Borrowed subtree traversal | `WmoRuntimeMeshFinalizer` | Exact Resource reference; not retained by preparer | One cached call |
+| Output | Success flag | Preparer | Loader | Value | Immediate |
+| Side effect | Mesh refresh, optional child removal and shadow mutation | Preparer | Borrowed subtree | SceneTree remains loader/placement-owned | Until subtree release |
+
+No filesystem, ResourceLoader, worker, RID, cache, queue, placement, attachment,
+Editor-owner or diagnostic side effect is introduced.
+
+## Data flow
+
+```mermaid
+flowchart LR
+    Input[Borrowed root + path kind + policies] --> Valid{Root valid?}
+    Valid -->|no| False[Return false]
+    Valid -->|yes cached| Walk[Parent-before-children traversal]
+    Valid -->|yes live| Policy
+    Walk --> Mesh{MeshInstance or non-null MultiMesh?}
+    Mesh -->|yes| Finalize[WmoRuntimeMeshFinalizer.finalize_mesh]
+    Mesh -->|no| Next[Continue]
+    Finalize --> Next
+    Next --> Policy[Apply direct Occluders and shadow policies]
+    Policy --> True[Return true]
+```
+
+## Main sequence
+
+```mermaid
+sequenceDiagram
+    participant Loader as StreamingWorldLoader
+    participant Preparer as WmoRuntimeScenePreparer
+    participant Finalizer as WmoRuntimeMeshFinalizer
+    participant Root as Borrowed WMO subtree
+    alt cached scene
+        Loader->>Preparer: prepare_cached_instance(root, directory, policies)
+        loop parent-before-children Mesh traversal
+            Preparer->>Finalizer: finalize_mesh(exact Mesh, directory)
+        end
+    else live-built duplicate
+        Loader->>Preparer: prepare_live_instance(root, policies)
+    end
+    Preparer->>Root: optional direct Occluders removal
+    Preparer->>Root: optional recursive shadow ON
+    Preparer-->>Loader: true/false
+    Loader->>Loader: place, attach, register and own lifetime
+```
+
+## Dependency diagram
+
+```mermaid
+flowchart TB
+    Loader[StreamingWorldLoader] --> Preparer[WmoRuntimeScenePreparer]
+    Preparer --> Finalizer[WmoRuntimeMeshFinalizer]
+    Preparer --> Engine[Node3D / GeometryInstance3D / Mesh / MultiMesh]
+    Preparer -. no dependency .-> IO[ResourceLoader / FileAccess]
+    Preparer -. no dependency .-> Queue[WMO queues / RenderBudgetScheduler]
+    Preparer -. no dependency .-> Placement[WmoPlacementResolver / Registry]
+```
+
+## Ownership, threading and resources
+
+- Calls are main-thread only because Mesh Resources and SceneTree nodes mutate.
+- The loader/placement registry retains ownership of the root and descendants.
+- Mesh finalization receives exact borrowed Resource identities.
+- A removed direct `Occluders` child is detached and `queue_free()`d as before.
+- The service retains no Node, Resource, RID, path, collection or state after return.
+
+## Errors, cancellation and recovery
+
+| Failure/state | Detection | Behavior | Recovery |
+|---|---|---|---|
+| Null/freed root | Guard | Return false, no traversal | Caller drops/retries stale placement |
+| Missing finalizer composition | Null dependency | Skip Mesh refresh but apply render policy | Fix renderer composition before cached use |
+| Null Mesh | Exact finalizer call for MeshInstance; finalizer handles null | Continue traversal | Cache rebuild/finalizer diagnostics |
+| Null MultiMesh or its Mesh | Guard/finalizer contract | Skip null MultiMesh; finalizer handles null Mesh | Continue safely |
+| Occlusion disabled | Direct-child lookup | Detach and queue-free `Occluders` | Reinstantiate to restore subtree |
+| Shadows disabled | Policy branch | Preserve current node settings | Re-run with enabled policy if required |
+| Placement cancellation/shutdown | Loader lifecycle | Service has no retained work to cancel | Existing subtree release/drain order |
+
+## Configuration and capabilities
+
+The service introduces no setting. It receives existing
+`enable_occlusion_culling` and `wmo_cast_shadows` values. The direct-child name
+`Occluders` and shadow-ON behavior are compatibility rules, not new capabilities.
+
+## Persistence, cache and migration
+
+No serialized format or cache version changes. Cached Mesh refresh metadata
+continues to belong to `WmoRuntimeMeshFinalizer`; no rebake or migration is needed.
+
+## Diagnostics and observability
+
+The preparer emits no log or metric. Loader placement/build metrics and the Mesh
+finalizer contracts remain the diagnostic surfaces.
+
+## Verification
+
+- `verify_wmo_runtime_scene_preparer.gd` covers cached parent-before-children
+  Mesh/MultiMesh identity, directory forwarding, null MultiMesh, direct versus
+  nested `Occluders`, enabled/preserved shadows, live finalizer suppression,
+  missing dependency, invalid roots, source boundaries and 1,000 traversals.
+- Adjacent WMO finalizer/cache/queue/shutdown and checkpoint checks protect the
+  unchanged lifecycle and presentation behavior.
+- Fidelity evidence is exact behavior-preserving extraction; no asset-backed or
+  original-client 3.3.5a visual-parity claim is added.
+
+The synthetic budget is 1,000 two-Mesh cached preparations under one second.
+Asset-backed CPU/GPU p95/p99, traversal and leak measurements remain pending.
+
+## Extension points
+
+- Asset-backed traversal can validate material identity and subtree lifetime
+  without expanding this service contract.
+- Portal/room visibility requires its own documented WMO service and evidence;
+  it must not be hidden inside generic subtree preparation.
+
+## Capability status
+
+| Capability | Status | Evidence | Gap/next step |
+|---|---|---|---|
+| Cached WMO subtree Mesh finalization | Implemented extraction | Exact traversal/resource/directory contract | Asset-backed visual/GPU p95/p99 pending |
+| Live/cached render policy | Implemented extraction | Direct occluder and recursive shadow contract | Portal/room and asset-backed traversal pending |
+| Placement/attachment/lifetime | Loader-owned | Existing registry/shutdown regressions | Further orchestration extraction pending |
+
+## Known gaps and risks
+
+- Recursive Mesh finalization and shadow mutation remain synchronous main-thread work.
+- The missing-finalizer branch degrades safely for isolated tests but production
+  composition must always inject `WmoRuntimeMeshFinalizer`.
+- No private WMO corpus, portal/room behavior, long traversal, leak/GPU timing or
+  paired original-client capture is included.
+
+## Source map
+
+| Path | Responsibility |
+|---|---|
+| `src/render/wmo/wmo_runtime_scene_preparer.gd` | Cached/live subtree traversal and render policy |
+| `src/render/wmo/wmo_runtime_mesh_finalizer.gd` | Borrowed Mesh refresh/version/material rules |
+| `src/scenes/streaming/streaming_world_loader.gd` | Composition, instantiation, placement, attachment and lifetime |
+| `src/tools/verify_wmo_runtime_scene_preparer.gd` | Synthetic traversal/policy/boundary/timing regression |
+
+## Related decisions and references
+
+- [`wmo-runtime-mesh-finalizer.md`](wmo-runtime-mesh-finalizer.md)
+- [`wmo-scene-resource-finalizer.md`](wmo-scene-resource-finalizer.md)
+- [`wmo-render-group-materializer.md`](wmo-render-group-materializer.md)
+- [`world-renderer.md`](world-renderer.md)
+- [`../../RENDER.md`](../../RENDER.md)
+- [`../../targets/roadmap/02-rendering-and-graphics.md`](../../targets/roadmap/02-rendering-and-graphics.md)
diff --git a/docs/modules/world-renderer.md b/docs/modules/world-renderer.md
index 06f2fbd..5c258ad 100644
--- a/docs/modules/world-renderer.md
+++ b/docs/modules/world-renderer.md
@@ -7,7 +7,7 @@
 | Status | Partial |
 | Target/work package | M00 baseline; `M01-RND-STREAMING-FOCUS-001`; `M01-QAR-SERVER-SPAWN-RENDERER-001`; M03 facade/planner/scheduler/internal-access/ground/environment/entity packages; M03 terrain packages; M03 M2 packages; M03 WMO placement package |
 | Owners | Renderer workstream / milestone integrator |
-| Last verified | Worktree `work/sindo-main-codex/m03-wmo-render-group-materializer`, 2026-08-01 |
+| Last verified | Worktree `work/sindo-main-codex/m03-wmo-runtime-scene-preparer`, 2026-08-01 |
 | Profiles/capabilities | `Performance`, `Balanced`, `High`, `Custom`; Blizzlike fidelity incomplete |
 
 ## Purpose
@@ -72,6 +72,8 @@ flowchart LR
     WmoBuildQueue --> Loader
     Loader --> WmoGroupMaterializer[WmoRenderGroupMaterializer]
     WmoGroupMaterializer --> Scene
+    Loader --> WmoScenePreparer[WmoRuntimeScenePreparer]
+    WmoScenePreparer --> Scene
     Native --> Parsed[Parsed tile/model data]
     Parsed --> Loader
     Loader --> Scene[SceneTree nodes]
@@ -167,6 +169,7 @@ from externally reading/writing loader-private queue, task, cache and tile-state
 | `WmoRenderBuildStepPlanner.plan_step` | Internal pure WMO service | Selects one mesh-first lightweight render-group operation and next cursors | Main/any thread; stateless | Raw integer comparisons are preserved without clamping |
 | `WmoRenderBuildQueue` / `WmoRenderBuildJob` | Internal WMO pending-state service | Owns typed root/resource/cursor jobs and FIFO placement keys | Renderer main thread; map session | Invalid enqueue rejected; duplicate/stale behavior preserved |
 | `WmoRenderGroupMaterializer.materialize_mesh_group/materialize_multimesh_group` | Internal WMO scene-materialization service | Creates, configures and attaches one indexed lightweight render group | Renderer main thread; stateless after each call | Invalid parent/resource/index returns null without attachment |
+| `WmoRuntimeScenePreparer.prepare_cached_instance/prepare_live_instance` | Internal WMO subtree-preparation service | Preserves cached/live Mesh-finalization distinction, direct occluder policy and recursive shadow enabling | Renderer main thread; stateless after each call | Null/freed root returns false |
 | `WmoRenderResourceCacheState` | Internal WMO cache-state service | Owns validated Resources, negative entries and pending cache paths | Renderer main thread; map/cache session | Invalid/occupied request and unknown completion are rejected |
 | `WmoRenderResourceFinalizer` | Internal WMO terminal-I/O service | Polls lightweight render requests, validates script/format and publishes Resource/missing outcomes | Renderer main thread; stateless across calls | Non-terminal retained; failed/null/wrong/stale complete missing |
 | `WmoSceneResourceCacheState` | Internal WMO cache-state service | Owns validated PackedScenes, negative entries and pending `.tscn` paths | Renderer main thread; map/cache session | Direct missing and terminal request transitions remain distinct |
@@ -210,6 +213,7 @@ loader configuration remains transitional composition data, not a caller API.
 | Internal WMO build step | Mesh/MultiMesh counts and job cursors | Loader / `WmoRenderBuildStepPlanner` | Loader materialization/cursor adapter | Fresh scalar Dictionary | One group operation |
 | Internal WMO pending build | Placement key, Node3D root, WMO Resource and cursors | Loader / `WmoRenderBuildQueue` | Loader drain and step planner adapter | Queue-owned job and strong references | Until cancel/clear/replacement |
 | Internal WMO group materialization | Parent root, exact Mesh/MultiMesh, indexed metadata and render settings | Loader / `WmoRenderGroupMaterializer` | Attached geometry node | Parent owns node and exact Resource reference | One main-thread group operation |
+| Internal WMO subtree preparation | Cached/live root, extracted directory and render policies | Loader / `WmoRuntimeScenePreparer` | Borrowed subtree and runtime Mesh finalizer | Loader/placement owns subtree; preparer retains nothing | One main-thread instance preparation |
 | Internal WMO render cache | Normalized path, cache path and validated Resource | Loader / `WmoRenderResourceCacheState` | Loader lookup, ResourceLoader poll and build queue | State-owned Resource/path references; detached request snapshots | Until transient/full clear |
 | Internal WMO scene cache | Normalized path, `.tscn` path and validated PackedScene | Loader / `WmoSceneResourceCacheState` | Loader lookup, request poll and scene instantiation | State-owned PackedScene/path references; detached request snapshots | Until transient/full clear |
 | Internal ADT water load | Tile key, ADT path, task ID and parsed Dictionary | Loader/worker / `AdtWaterLoadPipelineState` | Loader task start, budgeted drain and finalization | State-owned records; mutex result mailbox | Request through result completion/reset |
@@ -419,6 +423,8 @@ sequenceDiagram
   strong root/resource references without freeing engine objects.
   `WmoRenderGroupMaterializer` owns indexed MeshInstance3D/MultiMeshInstance3D
   creation, render settings and attachment without retaining engine objects.
+  `WmoRuntimeScenePreparer` owns cached-only Mesh traversal/finalization plus the
+  shared direct-Occluders and recursive shadow policies for cached/live roots.
   `WmoRenderResourceCacheState` owns validated render Resources, negative entries
   and pending cache paths; `WmoRenderResourceFinalizer` owns its terminal
   ResourceLoader polling and script/format validation. `WmoSceneResourceCacheState`
@@ -567,6 +573,9 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 - WMO render group materializer contract: exact Resource identity, indexed and
   fallback names/transforms, render settings, attachment, source ownership and
   bounded main-thread timing.
+- WMO runtime scene preparer contract: cached/live finalizer distinction,
+  exact Mesh traversal order, direct occluder removal, recursive shadow policy,
+  ownership boundaries and bounded main-thread timing.
 - WMO render Resource cache contract: invalid/duplicate request rejection,
   validated/missing terminal transitions, transient/full reset, detached sorted
   diagnostics, loader-owned version validation and bounded timing.
@@ -628,6 +637,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | WMO render build step planner | Implemented extraction | Scene-free order/cursor/source/timing contract | Asset-backed traversal p95/p99 pending |
 | WMO render build queue | Implemented extraction | Typed lifecycle/order/ownership/source/timing contract | Asset-backed traversal/leak evidence pending |
 | WMO render group materializer | Implemented extraction | Synthetic Resource/name/transform/render/attachment/source/timing contract | Asset-backed visual/leak/GPU p95/p99 pending |
+| WMO runtime scene preparer | Implemented extraction | Synthetic cached/live traversal/occluder/shadow/source/timing contract | Asset-backed visual/leak/GPU p95/p99 pending |
 | WMO render Resource cache state | Implemented extraction | Scene-free lifecycle/exclusivity/source/timing plus shutdown contract | Asset-backed traversal/leak evidence pending |
 | WMO render Resource finalizer | Implemented extraction | Status/order/script/format/adoption/source/timing contract | Serialized/asset-backed corrupt-cache and leak evidence pending |
 | WMO scene Resource cache state | Implemented extraction | Scene-free lifecycle/direct-missing/source/timing plus shutdown contract | Asset-backed traversal/leak evidence pending |
@@ -711,6 +721,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | `src/render/wmo/wmo_scene_resource_finalizer.gd` | Cached WMO terminal polling, probe validation/lifetime and publication |
 | `src/render/wmo/wmo_runtime_mesh_finalizer.gd` | Cached WMO runtime refresh admission, surface iteration and material reconstruction |
 | `src/render/wmo/wmo_render_group_materializer.gd` | Indexed lightweight WMO geometry-node creation, render setup and attachment |
+| `src/render/wmo/wmo_runtime_scene_preparer.gd` | Cached/live WMO subtree Mesh traversal and render policy |
 | `src/render/streaming/streaming_target_planner.gd` | Scene-free wanted/retained ADT target calculation |
 | `src/render/streaming/streaming_target_policy.gd` | Immutable renderer radius/prefetch policy |
 | `src/render/streaming/streaming_target_plan.gd` | Immutable planner result with read-only tile-key sets |
@@ -749,6 +760,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | `src/tools/verify_wmo_scene_resource_finalizer.gd` | WMO scene status/order/probe/lifetime/adoption/boundary/timing regression |
 | `src/tools/verify_wmo_runtime_mesh_finalizer.gd` | WMO Mesh identity/version/material-definition/boundary/timing regression |
 | `src/tools/verify_wmo_render_group_materializer.gd` | WMO render-group Resource/name/transform/render/attachment/boundary/timing regression |
+| `src/tools/verify_wmo_runtime_scene_preparer.gd` | WMO cached/live traversal/occluder/shadow/boundary/timing regression |
 | `src/tools/verify_streaming_target_planner.gd` | Planner behavior, dependency and bounded timing regression |
 | `src/tools/verify_render_budget_scheduler.gd` | Scheduler bounds, shared-lane priority, cancellation and timing regression |
 | `src/tools/verify_renderer_internal_access.gd` | Gameplay/EditorPlugin/registered renderer-tool boundary gate derived from private streamer fields |
diff --git a/src/render/wmo/wmo_runtime_scene_preparer.gd b/src/render/wmo/wmo_runtime_scene_preparer.gd
new file mode 100644
index 0000000..015104f
--- /dev/null
+++ b/src/render/wmo/wmo_runtime_scene_preparer.gd
@@ -0,0 +1,80 @@
+class_name WmoRuntimeScenePreparer
+extends RefCounted
+
+## Applies the existing cached/live WMO subtree preparation rules on the
+## renderer main thread. Placement, attachment and subtree lifetime stay caller-owned.
+
+var _runtime_mesh_finalizer: Object
+
+
+func _init(runtime_mesh_finalizer: Object) -> void:
+	_runtime_mesh_finalizer = runtime_mesh_finalizer
+
+
+## Prepares an instantiated cached WMO scene by finalizing every borrowed Mesh,
+## then applying the historical direct Occluders-child and shadow policies.
+## Returns false for a null/freed root without mutating or retaining anything.
+func prepare_cached_instance(
+		instance: Node3D,
+		extracted_directory: String,
+		enable_occlusion_culling: bool,
+		cast_shadows: bool) -> bool:
+	if instance == null or not is_instance_valid(instance):
+		return false
+	_finalize_meshes_in_subtree(instance, extracted_directory)
+	_apply_runtime_render_policy(instance, enable_occlusion_culling, cast_shadows)
+	return true
+
+
+## Prepares a duplicated live-built WMO without re-finalizing its Meshes.
+## Returns false for a null/freed root without mutating or retaining anything.
+func prepare_live_instance(
+		instance: Node3D,
+		enable_occlusion_culling: bool,
+		cast_shadows: bool) -> bool:
+	if instance == null or not is_instance_valid(instance):
+		return false
+	_apply_runtime_render_policy(instance, enable_occlusion_culling, cast_shadows)
+	return true
+
+
+func _finalize_meshes_in_subtree(node: Node, extracted_directory: String) -> void:
+	if _runtime_mesh_finalizer != null:
+		if node is MeshInstance3D:
+			_runtime_mesh_finalizer.call(
+				"finalize_mesh",
+				(node as MeshInstance3D).mesh,
+				extracted_directory
+			)
+		elif node is MultiMeshInstance3D:
+			var multimesh := (node as MultiMeshInstance3D).multimesh
+			if multimesh != null:
+				_runtime_mesh_finalizer.call(
+					"finalize_mesh",
+					multimesh.mesh,
+					extracted_directory
+				)
+	for child in node.get_children():
+		_finalize_meshes_in_subtree(child, extracted_directory)
+
+
+func _apply_runtime_render_policy(
+		instance: Node3D,
+		enable_occlusion_culling: bool,
+		cast_shadows: bool) -> void:
+	if not enable_occlusion_culling:
+		var occluders := instance.get_node_or_null("Occluders")
+		if occluders != null:
+			instance.remove_child(occluders)
+			occluders.queue_free()
+	if cast_shadows:
+		_enable_shadow_casting_recursive(instance)
+
+
+func _enable_shadow_casting_recursive(node: Node) -> void:
+	if node is GeometryInstance3D:
+		(node as GeometryInstance3D).cast_shadow = (
+			GeometryInstance3D.SHADOW_CASTING_SETTING_ON
+		)
+	for child in node.get_children():
+		_enable_shadow_casting_recursive(child)
diff --git a/src/render/wmo/wmo_runtime_scene_preparer.gd.uid b/src/render/wmo/wmo_runtime_scene_preparer.gd.uid
new file mode 100644
index 0000000..397b52d
--- /dev/null
+++ b/src/render/wmo/wmo_runtime_scene_preparer.gd.uid
@@ -0,0 +1 @@
+uid://d1t0vlkco8kw8
diff --git a/src/scenes/streaming/streaming_world_loader.gd b/src/scenes/streaming/streaming_world_loader.gd
index fea2a65..ecadaa0 100644
--- a/src/scenes/streaming/streaming_world_loader.gd
+++ b/src/scenes/streaming/streaming_world_loader.gd
@@ -39,6 +39,9 @@ const WMO_RUNTIME_MESH_FINALIZER_SCRIPT := preload(
 const WMO_RENDER_GROUP_MATERIALIZER_SCRIPT := preload(
 	"res://src/render/wmo/wmo_render_group_materializer.gd"
 )
+const WMO_RUNTIME_SCENE_PREPARER_SCRIPT := preload(
+	"res://src/render/wmo/wmo_runtime_scene_preparer.gd"
+)
 const M2_BUILDER_SCRIPT := preload("res://addons/mpq_extractor/loaders/m2_builder.gd")
 const M2_NATIVE_ANIMATOR_SCRIPT := preload("res://src/scenes/streaming/m2_native_animator.gd")
 const STREAMING_FOCUS_SCRIPT := preload("res://src/domain/streaming/streaming_focus.gd")
@@ -385,6 +388,9 @@ var _wmo_runtime_mesh_finalizer := WMO_RUNTIME_MESH_FINALIZER_SCRIPT.new(
 	WMO_BUILDER_SCRIPT
 )
 var _wmo_render_group_materializer := WMO_RENDER_GROUP_MATERIALIZER_SCRIPT.new()
+var _wmo_runtime_scene_preparer := WMO_RUNTIME_SCENE_PREPARER_SCRIPT.new(
+	_wmo_runtime_mesh_finalizer
+)
 var _wmo_missing_cache: Dictionary = {}
 var _wmo_placement_resolver := WMO_PLACEMENT_RESOLVER_SCRIPT.new()
 var _world_wmo_root: Node3D
@@ -3935,28 +3941,12 @@ func _instantiate_wmo_scene(rel_path: String, scene: PackedScene, placement: Dic
 
 
 func _prepare_runtime_wmo_instance(instance: Node3D) -> void:
-	_refresh_cached_wmo_materials_recursive(instance)
-	if not enable_occlusion_culling:
-		var occluders := instance.get_node_or_null("Occluders")
-		if occluders != null:
-			instance.remove_child(occluders)
-			occluders.queue_free()
-	if wmo_cast_shadows:
-		_apply_shadow_cast_recursive(instance, true)
-
-
-func _refresh_cached_wmo_materials_recursive(node: Node) -> void:
-	if node is MeshInstance3D:
-		_wmo_runtime_mesh_finalizer.finalize_mesh(
-			(node as MeshInstance3D).mesh,
-			extracted_dir
-		)
-	elif node is MultiMeshInstance3D:
-		var multimesh := (node as MultiMeshInstance3D).multimesh
-		if multimesh != null:
-			_wmo_runtime_mesh_finalizer.finalize_mesh(multimesh.mesh, extracted_dir)
-	for child in node.get_children():
-		_refresh_cached_wmo_materials_recursive(child)
+	_wmo_runtime_scene_preparer.prepare_cached_instance(
+		instance,
+		extracted_dir,
+		enable_occlusion_culling,
+		wmo_cast_shadows
+	)
 
 
 func _cancel_wmo_build_job(tile_key: String) -> void:
@@ -4466,18 +4456,6 @@ func _apply_visibility_range_recursive(node: Node, range_end: float) -> void:
 		_apply_visibility_range_recursive(child, range_end)
 
 
-func _apply_shadow_cast_recursive(node: Node, cast_shadows: bool) -> void:
-	if node is GeometryInstance3D:
-		var geometry := node as GeometryInstance3D
-		geometry.cast_shadow = (
-			GeometryInstance3D.SHADOW_CASTING_SETTING_ON
-			if cast_shadows
-			else GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
-		)
-	for child in node.get_children():
-		_apply_shadow_cast_recursive(child, cast_shadows)
-
-
 func _strip_occluders_recursive(node: Node) -> void:
 	for child in node.get_children():
 		if child is OccluderInstance3D:
@@ -4659,13 +4637,11 @@ func _instantiate_wmo_world(rel_path: String, placement: Dictionary) -> Node3D:
 	# WMOs are parented to _terrain_root, whose position absorbs the editor
 	# offset — use world-space placement.pos directly (no tile_origin subtraction).
 	instance.transform = _wmo_placement_resolver.resolve_world_transform(placement)
-	if not enable_occlusion_culling:
-		var occluders := instance.get_node_or_null("Occluders")
-		if occluders != null:
-			instance.remove_child(occluders)
-			occluders.queue_free()
-	if wmo_cast_shadows:
-		_apply_shadow_cast_recursive(instance, true)
+	_wmo_runtime_scene_preparer.prepare_live_instance(
+		instance,
+		enable_occlusion_culling,
+		wmo_cast_shadows
+	)
 	return instance
 
 
diff --git a/src/tools/verify_wmo_runtime_mesh_finalizer.gd b/src/tools/verify_wmo_runtime_mesh_finalizer.gd
index a5a2506..3b84965 100644
--- a/src/tools/verify_wmo_runtime_mesh_finalizer.gd
+++ b/src/tools/verify_wmo_runtime_mesh_finalizer.gd
@@ -7,6 +7,7 @@ const FINALIZER_SCRIPT := preload(
 	"res://src/render/wmo/wmo_runtime_mesh_finalizer.gd"
 )
 const FINALIZER_PATH := "res://src/render/wmo/wmo_runtime_mesh_finalizer.gd"
+const SCENE_PREPARER_PATH := "res://src/render/wmo/wmo_runtime_scene_preparer.gd"
 const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"
 
 
@@ -42,7 +43,7 @@ func _initialize() -> void:
 		quit(1)
 		return
 	print(
-		"WMO_RUNTIME_MESH_FINALIZER PASS cases=27 iterations=1000 elapsed_ms=%.3f"
+		"WMO_RUNTIME_MESH_FINALIZER PASS cases=28 iterations=1000 elapsed_ms=%.3f"
 		% elapsed_milliseconds
 	)
 	quit(0)
@@ -198,6 +199,7 @@ func _verify_missing_builder_contract(failures: Array[String]) -> void:
 func _verify_source_boundaries(failures: Array[String]) -> void:
 	var loader_source := _read_text(LOADER_PATH, failures)
 	var finalizer_source := _read_text(FINALIZER_PATH, failures)
+	var scene_preparer_source := _read_text(SCENE_PREPARER_PATH, failures)
 	_expect_true(
 		loader_source.contains("WMO_RUNTIME_MESH_FINALIZER_SCRIPT.new("),
 		"loader composes runtime Mesh finalizer",
@@ -229,9 +231,14 @@ func _verify_source_boundaries(failures: Array[String]) -> void:
 			"finalizer owns %s" % owned_token,
 			failures
 		)
+	_expect_false(
+		loader_source.contains("func _refresh_cached_wmo_materials_recursive("),
+		"loader releases scene traversal",
+		failures
+	)
 	_expect_true(
-		loader_source.contains("func _refresh_cached_wmo_materials_recursive(node: Node)"),
-		"loader retains scene traversal",
+		scene_preparer_source.contains("func _finalize_meshes_in_subtree("),
+		"runtime scene preparer owns scene traversal",
 		failures
 	)
 
diff --git a/src/tools/verify_wmo_runtime_scene_preparer.gd b/src/tools/verify_wmo_runtime_scene_preparer.gd
new file mode 100644
index 0000000..65ed7ea
--- /dev/null
+++ b/src/tools/verify_wmo_runtime_scene_preparer.gd
@@ -0,0 +1,308 @@
+extends SceneTree
+
+## Asset-free cached/live WMO subtree traversal, render-policy, ownership and
+## bounded-timing regression for runtime scene preparation.
+
+const PREPARER_SCRIPT := preload(
+	"res://src/render/wmo/wmo_runtime_scene_preparer.gd"
+)
+const PREPARER_PATH := "res://src/render/wmo/wmo_runtime_scene_preparer.gd"
+const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"
+
+
+class FakeRuntimeMeshFinalizer extends RefCounted:
+	var finalized_meshes: Array[Mesh] = []
+	var extracted_directories: Array[String] = []
+
+	func finalize_mesh(mesh: Mesh, extracted_directory: String) -> Mesh:
+		finalized_meshes.append(mesh)
+		extracted_directories.append(extracted_directory)
+		return mesh
+
+
+func _initialize() -> void:
+	var failures: Array[String] = []
+	_verify_cached_instance_contract(failures)
+	_verify_enabled_occlusion_and_disabled_shadow_contract(failures)
+	_verify_live_instance_contract(failures)
+	_verify_missing_finalizer_and_invalid_input(failures)
+	_verify_source_boundaries(failures)
+	var elapsed_milliseconds := _verify_bounded_timing(failures)
+	if not failures.is_empty():
+		for failure in failures:
+			push_error("WMO_RUNTIME_SCENE_PREPARER: %s" % failure)
+		quit(1)
+		return
+	print(
+		"WMO_RUNTIME_SCENE_PREPARER PASS cases=31 iterations=1000 elapsed_ms=%.3f"
+		% elapsed_milliseconds
+	)
+	quit(0)
+
+
+func _verify_cached_instance_contract(failures: Array[String]) -> void:
+	var finalizer := FakeRuntimeMeshFinalizer.new()
+	var preparer := PREPARER_SCRIPT.new(finalizer)
+	var fixture := _create_scene_fixture()
+	var instance: Node3D = fixture["root"]
+	var mesh_instance: MeshInstance3D = fixture["mesh_instance"]
+	var multimesh_instance: MultiMeshInstance3D = fixture["multimesh_instance"]
+	var direct_occluders: Node3D = fixture["direct_occluders"]
+	var nested_occluders: Node3D = fixture["nested_occluders"]
+	get_root().add_child(instance)
+	var prepared: bool = preparer.prepare_cached_instance(
+		instance,
+		"res://fixture/extracted",
+		false,
+		true
+	)
+	_expect_true(prepared, "cached instance accepted", failures)
+	_expect_equal(finalizer.finalized_meshes.size(), 2, "two non-null Meshes finalized", failures)
+	_expect_same(finalizer.finalized_meshes[0], mesh_instance.mesh, "Mesh traversal first", failures)
+	_expect_same(
+		finalizer.finalized_meshes[1],
+		multimesh_instance.multimesh.mesh,
+		"MultiMesh Mesh traversal second",
+		failures
+	)
+	_expect_true(
+		finalizer.extracted_directories == [
+			"res://fixture/extracted",
+			"res://fixture/extracted",
+		],
+		"extracted directory forwarded for every Mesh",
+		failures
+	)
+	_expect_true(instance.get_node_or_null("Occluders") == null, "direct Occluders removed", failures)
+	_expect_true(direct_occluders.is_queued_for_deletion(), "direct Occluders queued for deletion", failures)
+	_expect_same(
+		nested_occluders.get_parent(),
+		fixture["nested_root"],
+		"nested same-name node retained",
+		failures
+	)
+	_expect_equal(
+		mesh_instance.cast_shadow,
+		GeometryInstance3D.SHADOW_CASTING_SETTING_ON,
+		"Mesh shadows enabled",
+		failures
+	)
+	_expect_equal(
+		multimesh_instance.cast_shadow,
+		GeometryInstance3D.SHADOW_CASTING_SETTING_ON,
+		"MultiMesh shadows enabled",
+		failures
+	)
+	instance.free()
+
+
+func _verify_enabled_occlusion_and_disabled_shadow_contract(
+		failures: Array[String]) -> void:
+	var finalizer := FakeRuntimeMeshFinalizer.new()
+	var preparer := PREPARER_SCRIPT.new(finalizer)
+	var fixture := _create_scene_fixture()
+	var instance: Node3D = fixture["root"]
+	var mesh_instance: MeshInstance3D = fixture["mesh_instance"]
+	var multimesh_instance: MultiMeshInstance3D = fixture["multimesh_instance"]
+	mesh_instance.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_DOUBLE_SIDED
+	multimesh_instance.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
+	_expect_true(
+		preparer.prepare_cached_instance(instance, "res://data/extracted", true, false),
+		"enabled-occlusion cached instance accepted",
+		failures
+	)
+	_expect_same(
+		fixture["direct_occluders"].get_parent(),
+		instance,
+		"enabled occlusion retains direct child",
+		failures
+	)
+	_expect_equal(
+		mesh_instance.cast_shadow,
+		GeometryInstance3D.SHADOW_CASTING_SETTING_DOUBLE_SIDED,
+		"disabled shadow policy preserves Mesh value",
+		failures
+	)
+	_expect_equal(
+		multimesh_instance.cast_shadow,
+		GeometryInstance3D.SHADOW_CASTING_SETTING_OFF,
+		"disabled shadow policy preserves MultiMesh value",
+		failures
+	)
+	instance.free()
+
+
+func _verify_live_instance_contract(failures: Array[String]) -> void:
+	var finalizer := FakeRuntimeMeshFinalizer.new()
+	var preparer := PREPARER_SCRIPT.new(finalizer)
+	var fixture := _create_scene_fixture()
+	var instance: Node3D = fixture["root"]
+	_expect_true(
+		preparer.prepare_live_instance(instance, false, true),
+		"live instance accepted",
+		failures
+	)
+	_expect_equal(finalizer.finalized_meshes.size(), 0, "live path skips Mesh finalizer", failures)
+	_expect_true(instance.get_node_or_null("Occluders") == null, "live direct Occluders removed", failures)
+	_expect_equal(
+		fixture["mesh_instance"].cast_shadow,
+		GeometryInstance3D.SHADOW_CASTING_SETTING_ON,
+		"live Mesh shadows enabled",
+		failures
+	)
+	instance.free()
+
+
+func _verify_missing_finalizer_and_invalid_input(failures: Array[String]) -> void:
+	var preparer := PREPARER_SCRIPT.new(null)
+	var fixture := _create_scene_fixture()
+	var instance: Node3D = fixture["root"]
+	_expect_true(
+		preparer.prepare_cached_instance(instance, "res://data/extracted", false, true),
+		"missing finalizer retains render-policy preparation",
+		failures
+	)
+	_expect_true(instance.get_node_or_null("Occluders") == null, "missing finalizer still applies occluder policy", failures)
+	_expect_false(
+		preparer.prepare_cached_instance(null, "res://data/extracted", false, true),
+		"null cached root rejected",
+		failures
+	)
+	_expect_false(
+		preparer.prepare_live_instance(null, false, true),
+		"null live root rejected",
+		failures
+	)
+	instance.free()
+
+
+func _verify_source_boundaries(failures: Array[String]) -> void:
+	var preparer_source := FileAccess.get_file_as_string(PREPARER_PATH)
+	var loader_source := FileAccess.get_file_as_string(LOADER_PATH)
+	_expect_true(
+		loader_source.contains("WMO_RUNTIME_SCENE_PREPARER_SCRIPT.new("),
+		"loader composes runtime scene preparer",
+		failures
+	)
+	_expect_equal(
+		loader_source.count("_wmo_runtime_scene_preparer.prepare_cached_instance("),
+		1,
+		"loader delegates cached preparation once",
+		failures
+	)
+	_expect_equal(
+		loader_source.count("_wmo_runtime_scene_preparer.prepare_live_instance("),
+		1,
+		"loader delegates live preparation once",
+		failures
+	)
+	for released_token in [
+		"func _refresh_cached_wmo_materials_recursive(",
+		"func _apply_shadow_cast_recursive(",
+	]:
+		_expect_false(
+			loader_source.contains(released_token),
+			"loader releases %s" % released_token,
+			failures
+		)
+	for owned_token in [
+		"func _finalize_meshes_in_subtree(",
+		"instance.get_node_or_null(\"Occluders\")",
+		"instance.remove_child(occluders)",
+		"func _enable_shadow_casting_recursive(",
+		"GeometryInstance3D.SHADOW_CASTING_SETTING_ON",
+	]:
+		_expect_true(
+			preparer_source.contains(owned_token),
+			"preparer owns %s" % owned_token,
+			failures
+		)
+	for forbidden_dependency in [
+		"ResourceLoader.",
+		"FileAccess.",
+		"WorkerThreadPool.",
+		"RenderingServer.",
+		".owner =",
+		"add_child(",
+		"duplicate(",
+		"_wmo_render_build_queue",
+		"_render_budget_scheduler",
+	]:
+		_expect_false(
+			preparer_source.contains(forbidden_dependency),
+			"preparer omits %s ownership" % forbidden_dependency,
+			failures
+		)
+
+
+func _verify_bounded_timing(failures: Array[String]) -> float:
+	var finalizer := FakeRuntimeMeshFinalizer.new()
+	var preparer := PREPARER_SCRIPT.new(finalizer)
+	var fixture := _create_scene_fixture(false)
+	var instance: Node3D = fixture["root"]
+	var started_microseconds := Time.get_ticks_usec()
+	for iteration in 1000:
+		preparer.prepare_cached_instance(instance, "res://data/extracted", true, false)
+	var elapsed_milliseconds := float(Time.get_ticks_usec() - started_microseconds) / 1000.0
+	_expect_equal(finalizer.finalized_meshes.size(), 2000, "timing traversal complete", failures)
+	_expect_true(elapsed_milliseconds < 1000.0, "1000 preparations under one second", failures)
+	instance.free()
+	return elapsed_milliseconds
+
+
+func _create_scene_fixture(include_direct_occluders: bool = true) -> Dictionary:
+	var root := Node3D.new()
+	root.name = "FixtureWmo"
+	var mesh_instance := MeshInstance3D.new()
+	mesh_instance.name = "Exterior"
+	mesh_instance.mesh = ArrayMesh.new()
+	mesh_instance.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
+	root.add_child(mesh_instance)
+	var nested_root := Node3D.new()
+	nested_root.name = "Nested"
+	root.add_child(nested_root)
+	var multimesh := MultiMesh.new()
+	multimesh.transform_format = MultiMesh.TRANSFORM_3D
+	multimesh.mesh = ArrayMesh.new()
+	var multimesh_instance := MultiMeshInstance3D.new()
+	multimesh_instance.name = "Doodads"
+	multimesh_instance.multimesh = multimesh
+	multimesh_instance.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
+	nested_root.add_child(multimesh_instance)
+	var null_multimesh_instance := MultiMeshInstance3D.new()
+	nested_root.add_child(null_multimesh_instance)
+	var nested_occluders := Node3D.new()
+	nested_occluders.name = "Occluders"
+	nested_root.add_child(nested_occluders)
+	var direct_occluders: Node3D = null
+	if include_direct_occluders:
+		direct_occluders = Node3D.new()
+		direct_occluders.name = "Occluders"
+		root.add_child(direct_occluders)
+	return {
+		"root": root,
+		"mesh_instance": mesh_instance,
+		"nested_root": nested_root,
+		"multimesh_instance": multimesh_instance,
+		"nested_occluders": nested_occluders,
+		"direct_occluders": direct_occluders,
+	}
+
+
+func _expect_true(condition: bool, label: String, failures: Array[String]) -> void:
+	if not condition:
+		failures.append(label)
+
+
+func _expect_false(condition: bool, label: String, failures: Array[String]) -> void:
+	_expect_true(not condition, label, failures)
+
+
+func _expect_equal(actual: int, expected: int, label: String, failures: Array[String]) -> void:
+	if actual != expected:
+		failures.append("%s expected=%d actual=%d" % [label, expected, actual])
+
+
+func _expect_same(actual: Variant, expected: Variant, label: String, failures: Array[String]) -> void:
+	if not is_same(actual, expected):
+		failures.append(label)
diff --git a/src/tools/verify_wmo_runtime_scene_preparer.gd.uid b/src/tools/verify_wmo_runtime_scene_preparer.gd.uid
new file mode 100644
index 0000000..a8a65d9
--- /dev/null
+++ b/src/tools/verify_wmo_runtime_scene_preparer.gd.uid
@@ -0,0 +1 @@
+uid://bigpi11md6vxd