diff --git a/.trellis/spec/config/index.md b/.trellis/spec/config/index.md
index dcb5a72..9d8da4a 100644
--- a/.trellis/spec/config/index.md
+++ b/.trellis/spec/config/index.md
@@ -8,14 +8,14 @@
 
 ## 两层配置
 
-用户只写第一层，第二层是机器生成的中间产物：
+用户只写第一层；legacy QGIS 链路需要时才生成第二层中间产物：
 
 ```
 config/areas/<id>.json                          ← 你写的
         │  scripts/lib/area-config.js: normalizeAreaConfig()
         │  补默认值 + 推导输出路径
         ▼
-<areaDir>/_pipeline/osm2streets-qgis.config.json  ← 生成的，不要手改
+<areaDir>/_pipeline/osm2streets-qgis.config.json  ← legacy 生成的，不要手改
         │
         ▼  build-osm2streets-qgis.js / reimport-gpkg.js
 ```
@@ -65,7 +65,7 @@ cp config/examples/template.json config/areas/my-area.json
 
 | 字段 | 默认 | 说明 |
 |---|---|---|
-| `intermediates` | `true` | 旧名 `qgis` 仍被接受 |
+| `intermediates` | `false` | native-only 默认；旧名 `qgis` 仍被接受，显式开启才运行 legacy |
 | `blender` | `true` | |
 | `cesium` | `true` | |
 | `compress` | `true` | 压缩 staged GLB，供随后发布使用 |
@@ -132,7 +132,7 @@ cp config/examples/template.json config/areas/my-area.json
 |---|---|---|
 | `treeStyle` | `"natural"` | 合法值见 `generate_scene.py` 的 `TREE_STYLES`（`natural`、`procedural`、`shapespark`） |
 | `officeOverrides` | `""` | 旧名 `office_overrides` 仍被接受 |
-| `roadProvider` | `"osm2streets"` | Blender 道路来源。`"native"` 时仅使用 `native-road/` 的道路、路口和人行道面；可由 `build:area --road-provider native` 临时覆盖。 |
+| `roadProvider` | `"native"` | Blender 道路来源。`"native"` 时仅使用 `native-road/` 的道路、路口和人行道面；`"osm2streets"` 仅用于显式 legacy/debug 构建。 |
 
 ### `compress`
 
diff --git a/.trellis/spec/pipeline/cli-and-stages.md b/.trellis/spec/pipeline/cli-and-stages.md
index ec02fb7..3a5ee06 100644
--- a/.trellis/spec/pipeline/cli-and-stages.md
+++ b/.trellis/spec/pipeline/cli-and-stages.md
@@ -1364,9 +1364,9 @@ gpkg: path.resolve(outputOverrides.gpkg || path.join(areaDir, `${fileStem}.gpkg`
 
 | 阶段 | 做什么 | 读 | 写 |
 |---|---|---|---|
-| `intermediates` | OSM → osm2streets GeoJSON → GeoPackage → QGIS 工程 + 预览图 | `.osm` | `osm2streets_web_out/`、`.gpkg`、`.qgz`、`-preview.png` |
+| `intermediates` |（显式 legacy）OSM → osm2streets GeoJSON → GeoPackage → QGIS 工程 + 预览图 | `.osm` | `osm2streets_web_out/`、`.gpkg`、`.qgz`、`-preview.png` |
 | `reimport` | GeoPackage → GeoJSON（**反向**） | `.gpkg` | `osm2streets_web_out/` |
-| `blender` | OSM + GeoJSON → 场景 | `.osm`、`osm2streets_web_out/` | `.blend`、`.png` |
+| `blender` | 默认 OSM → native road compiler → Blender 场景；legacy provider 时读取 GeoJSON | `.osm`、`native-road/`（legacy 为 `osm2streets_web_out/`） | `.blend`、`.png` |
 | `cesium` | 场景 → static staging GLB + manifest | `.blend` | `_pipeline/package-staging/models/*.glb`、staged manifest；动态 GLB 到 `_preview/` |
 | `compress` | 压缩 Cesium staging 主模型 | staged `.glb`、manifest | 压缩 staged `.glb`、manifest |
 | `package` | 校验并原子发布静态资产包 | staging manifest 与 models | `package/manifest.json`、`package/models/*.glb` |
@@ -1386,12 +1386,11 @@ gpkg: path.resolve(outputOverrides.gpkg || path.join(areaDir, `${fileStem}.gpkg`
 
 未知阶段名**抛错并列出合法值**（`:181`），不静默忽略。
 
-### `all` 不含 `reimport`
+### `all` 是 native-only 完整构建
 
 ```js
-// 'reimport' is deliberately absent from 'all': it is a recovery step for
-// hand-edited GeoPackages, never part of a full build.        build-area.js:159-160
-all: ["intermediates", "blender", "cesium", "compress", "package", "preview"],
+// Legacy intermediates/reimport are deliberately absent from 'all'.
+all: ["blender", "cesium", "compress", "package", "preview"],
 ```
 
 `compress`、`package`、`preview` 均在 `all` 中，确保完整构建以压缩后的可复用静态 package
diff --git a/.trellis/spec/pipeline/index.md b/.trellis/spec/pipeline/index.md
index c14afb5..fdff2dc 100644
--- a/.trellis/spec/pipeline/index.md
+++ b/.trellis/spec/pipeline/index.md
@@ -30,7 +30,7 @@ config/areas/<id>.json
       ▼  build-area.js — 阶段调度
    _pipeline/osm2streets-qgis.config.json          （派生配置）
       │
-      ├─[intermediates]─▶ build-osm2streets-qgis.js
+      ├─[intermediates]─▶ build-osm2streets-qgis.js（显式 legacy/reference）
       │                     osm2streets-js-node 解析 .osm
       │                     → splitLayers() 拆成九个图层
       │                     → normalize-lane-arrows.py（QGIS Python）
@@ -45,8 +45,8 @@ config/areas/<id>.json
       │                     → 重建 scene.geojson + scene_style.json
       │                     → _pipeline/stages/reimport.manifest.json
       │
-      ├─[blender]───────▶ Blender + blender/generate_scene.py
-      │                     读 .osm + osm2streets_web_out/
+      ├─[blender]───────▶ compile-native-roads.js + Blender + blender/generate_scene.py
+      │                     默认读 .osm + native-road/
       │                     → <id>.blend + <id>.png
       │                     → _pipeline/stages/blender.manifest.json
       │
@@ -62,7 +62,7 @@ config/areas/<id>.json
       │                     → package/manifest.json + package/models/*.glb
       │                     → _pipeline/stages/package.manifest.json
       │
-      └─[preview]───────▶ 生成 <id>-cesium-preview.html
+      └─[preview]───────▶ 生成 <id>-cesium-preview.html（native 可无车辆路线）
       │                     + 拷贝 lib/cesium-preview.{js,css}
                             + _preview/ 车辆巡航路线、模型、动态信号
       │                     → _pipeline/stages/preview.manifest.json
diff --git a/.trellis/spec/preview/vehicle-routes.md b/.trellis/spec/preview/vehicle-routes.md
index 8dda1a8..d5eb522 100644
--- a/.trellis/spec/preview/vehicle-routes.md
+++ b/.trellis/spec/preview/vehicle-routes.md
@@ -31,7 +31,7 @@ classifyConnection(incomingEdge, outgoingEdge) =>
   `maneuvers`、`edgeIds`、`laneSegments` 与 `connectors`。道路区间来自匹配的 Driving lane polygon 中轴。
 - 路线拓扑以 `network.json` 的 internal road 和 intersection 为准；禁止把整个 OSM way 直接当作一条不可分割 edge。
 - connector 必须绑定同一个 internal intersection，并位于对应 `intersection_surface.geojson` 内或允许的边界容差内；越界时拒绝候选路线。
-- preview 必须将 `lane_polygons.geojson`、`network.json` 和 `intersection_surface.geojson` 作为强制输入；缺失或无效时在写产物前失败。
+- legacy osm2streets preview 必须将 `lane_polygons.geojson`、`network.json` 和 `intersection_surface.geojson` 作为强制输入；native preview 不读取这些文件，路线缺失时保留可用预览并省略车辆巡航。
 - route 经纬度由 Cesium 按 WGS84 直接放置；最终道路 GLB 必须由 WGS84 ECEF→ENU
   `Projector` 生成。禁止以固定米/度近似投影道路，否则即使 route 与 lane polygon
   完全一致，最终画面仍会随离锚点距离产生横向偏移。
diff --git a/README.md b/README.md
index 138ed4f..214a6d1 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 # OSM Asset Pipeline
 
-把单个园区/片区 OSM XML 转为可消费的 Blender 场景和 Cesium GLB。osm2streets GeoJSON、GeoPackage、QGIS 工程和预览图都是中间资产，用来提供道路几何、调试标线效果，以及给 Blender/Cesium 生成提供输入。
+原始 QGIS/osm2streets 基线保留在 Git tag `qgis-original-baseline-20260818`，用于回撤和对照；当前分支的默认生产链路是 native-only。
+
+把单个园区/片区 OSM XML 转为可消费的 Blender 场景和 Cesium GLB。Native road compiler 是默认生产道路来源；osm2streets GeoJSON、GeoPackage、QGIS 工程和预览图仅作为显式 legacy/debug 资产或 Workbench 参考层。
 
 ## 目标产物
 
@@ -17,17 +19,19 @@
 - `<area-id>-roads.glb`、`-buildings.glb`、`-vegetation.glb`、`-water.glb`：Cesium 分类检查用的辅助模型
 - `<area-id>.json`：Cesium 放置元数据和示例代码
 - `<area-id>-cesium-preview.html`：Cesium 本地预览页
-- `osm2streets_web_out/`：osm2streets GeoJSON 中间层
+- `native-road/`：native road compiler 的道路、路口、标线和信号灯运行时产物
+- `osm2streets_web_out/`：可选的 osm2streets/QGIS 参考中间层
 - `<area-id>.gpkg` / `<area-id>.qgz` / `<area-id>-preview.png`：QGIS 调试资产
 
 ## 环境
 
-需要：
+默认 native-only 构建需要：
 
-- QGIS 与 GDAL 工具链
 - Blender
 - Node.js / npm
 
+QGIS/GDAL 仅在显式运行 legacy `intermediates`/`reimport` 或 Workbench 参考链路时需要。
+
 macOS 默认使用 QGIS `/Applications/QGIS.app` 与 Blender
 `/Applications/Blender.app`。Linux 配置中，`qgisApp` 是安装前缀（通常为
 `/usr`），`blenderApp` 是可执行文件路径（通常为 `/usr/bin/blender`）。
@@ -66,7 +70,7 @@ npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json
 npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json --stages reimport
 ```
 
-`intermediates` 会生成 osm2streets GeoJSON、GeoPackage、QGIS 工程和 QGIS 预览图。`blender` 使用 OSM 和 osm2streets GeoJSON 生成 `.blend`/`.png`。`cesium` 从 `.blend` 导出包 staging，`compress` 压缩 staging 主 GLB，`package` 校验并原子发布 `package/`，`preview` 生成仅用于本地验证的 HTML 和 `_preview/` 动态描述符。`reimport` 把手工编辑过的 GeoPackage 回导为 GeoJSON，不含在 `all` 里，详见 [QGIS 手工修正工作流](#qgis-手工修正工作流)。
+默认构建依次由 native road compiler、Blender、Cesium、压缩、package 和 preview 组成，不读取 `osm2streets_web_out/`。native preview 在没有 legacy 路线文件时仍可用，只是不提供可选车辆巡航。`intermediates`/`reimport` 仍可显式运行 legacy QGIS 链路，详见 [QGIS 手工修正工作流](#qgis-手工修正工作流)。
 
 Cesium 预览默认显示完整场景。点击 `Inspect` 后会按道路、建筑、绿化与设施、水体加载辅助 GLB；该模式用于单独检查生成结果，主 GLB 是压缩后的下游交付资产。
 
@@ -148,9 +152,9 @@ outputs/<area-id>/_pipeline/stages/compress.manifest.json
 造成假 stale。
 
 manifest 记录阶段输入/输出文件的 bytes、mtime、sha256、耗时和结构摘要：前段记录 OSM /
-GeoJSON feature counts，Blender 记录 `.blend` / render，Cesium/压缩记录 GLB digest，
-preview 记录 GLB、metadata、`lane_polygons.geojson`、`network.json`、`intersection_surface.geojson`、
-车辆路线和 runtime 文件。巡航道路区间按 osm2streets internal road 匹配真实 Driving lane 中轴，
+native-road 或 legacy GeoJSON feature counts，Blender 记录 `.blend` / render，Cesium/压缩记录 GLB digest，
+preview 记录 GLB、metadata、provider 对应的道路输入、可选车辆路线和 runtime 文件。legacy
+巡航道路区间按 osm2streets internal road 匹配真实 Driving lane 中轴，native preview 可省略巡航，
 路口 connector 必须通过 intersection surface 越界检查。`diagnose:area` 会读取这些
 manifest；缺失或当前输入/输出 sha/bytes 不一致会在 `Stage manifests` 和 `Warnings`
 里标出来。
@@ -201,7 +205,7 @@ cp config/examples/template.json config/areas/my-area.json
   "qgisApp": "/Applications/QGIS.app",
   "blenderApp": "/Applications/Blender.app",
   "stages": {
-    "intermediates": true,
+    "intermediates": false,
     "blender": true,
     "cesium": true
   },
@@ -219,7 +223,8 @@ cp config/examples/template.json config/areas/my-area.json
   },
   "blender": {
     "treeStyle": "natural",
-    "officeOverrides": ""
+    "officeOverrides": "",
+    "roadProvider": "native"
   },
   "compress": {
     "textureSize": 768,
@@ -358,7 +363,7 @@ npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json
 - 这套流程假设你的手工修改已经保存在 `outputs/<area-id>/<area-id>.gpkg` 中
 - 所有图层先导出到临时目录并校验通过后才写回 `osm2streets_web_out/`；任一图层缺失或导出结果不是合法 FeatureCollection，整批都不落盘（`ogr2ogr` 遇到不存在的图层会留下 0 字节文件，直接覆盖会静默损坏数据）
 - `intermediates` 与 `reimport` 互斥，同时指定会直接报错：前者用 OSM 重建 `gpkg`，正好会抹掉后者要读回的手工修改
-- `blender,cesium` 阶段读取的是 `osm2streets_web_out/*.geojson`，不是直接读取 `gpkg`
+- 在显式 legacy provider 下，`blender,cesium` 阶段读取的是 `osm2streets_web_out/*.geojson`，不是直接读取 `gpkg`；native provider 不读取这些文件
 - 如果 Blender 当前环境不稳定，先确认 `geojson` 已完成回导，再单独排查 Blender 本身
 - 增删图层或调整 `z_index` 只需改 `scripts/lib/scene-layers.js`，构建、场景合并、场景样式、QGIS 工程会一并同步
 
diff --git a/config/areas/hanyang-block.json b/config/areas/hanyang-block.json
index a944842..86f57a9 100644
--- a/config/areas/hanyang-block.json
+++ b/config/areas/hanyang-block.json
@@ -5,7 +5,7 @@
   "qgisApp": "/Applications/QGIS.app",
   "blenderApp": "/Applications/Blender.app",
   "stages": {
-    "intermediates": true,
+    "intermediates": false,
     "blender": true,
     "cesium": true
   },
diff --git a/config/areas/nantaizi-lake-innovation-valley.json b/config/areas/nantaizi-lake-innovation-valley.json
index e9e6aac..959caed 100644
--- a/config/areas/nantaizi-lake-innovation-valley.json
+++ b/config/areas/nantaizi-lake-innovation-valley.json
@@ -5,7 +5,7 @@
   "qgisApp": "/Applications/QGIS.app",
   "blenderApp": "/Applications/Blender.app",
   "stages": {
-    "intermediates": true,
+    "intermediates": false,
     "blender": true,
     "cesium": true
   },
@@ -36,6 +36,7 @@
   },
   "blender": {
     "treeStyle": "shapespark",
-    "officeOverrides": ""
+    "officeOverrides": "",
+    "roadProvider": "native"
   }
 }
diff --git a/config/examples/template.json b/config/examples/template.json
index 9ca7207..45cff31 100644
--- a/config/examples/template.json
+++ b/config/examples/template.json
@@ -5,7 +5,7 @@
   "qgisApp": "/Applications/QGIS.app",
   "blenderApp": "/Applications/Blender.app",
   "stages": {
-    "intermediates": true,
+    "intermediates": false,
     "blender": true,
     "cesium": true
   },
@@ -37,7 +37,7 @@
   "blender": {
     "treeStyle": "natural",
     "officeOverrides": "",
-    "roadProvider": "osm2streets"
+    "roadProvider": "native"
   },
   "compress": {
     "textureSize": 768,
diff --git a/scripts/build-area.js b/scripts/build-area.js
index ef58ada..3dde72d 100755
--- a/scripts/build-area.js
+++ b/scripts/build-area.js
@@ -69,10 +69,10 @@ if (stages.compress) {
   compressCesiumGlb(area);
 }
 if (stages.package) {
-  publishPackage(area);
+  publishPackage(area, roadProvider);
 }
 if (stages.preview) {
-  writeCesiumPreview(area);
+  writeCesiumPreview(area, roadProvider);
 }
 
 console.log("Done.");
@@ -491,13 +491,16 @@ function compressCesiumGlb(area) {
   }
 }
 
-function publishPackage(area) {
+function publishPackage(area, roadProvider) {
   ensureFile(area.outputs.packageStagingManifest, "Staged package manifest");
-  ensureFile(area.outputs.trafficSignals, "Traffic signal anchors");
+  const trafficSignalsSource = roadProvider === "native"
+    ? path.join(area.outputs.nativeRoadDir, "traffic-signals.json")
+    : area.outputs.trafficSignals;
+  ensureFile(trafficSignalsSource, "Traffic signal anchors");
   const started = Date.now();
   const manifest = JSON.parse(fs.readFileSync(area.outputs.packageStagingManifest, "utf8"));
   fs.mkdirSync(area.outputs.packageStagingRuntimeDir, { recursive: true });
-  fs.copyFileSync(area.outputs.trafficSignals, area.outputs.packageStagingTrafficSignals);
+  fs.copyFileSync(trafficSignalsSource, area.outputs.packageStagingTrafficSignals);
   manifest.runtime = Array.isArray(manifest.runtime) ? manifest.runtime : [];
   if (!manifest.runtime.some((runtime) => runtime.id === "traffic-signals")) {
     manifest.runtime.push({ id: "traffic-signals", type: "traffic-signal-anchors", uri: "runtime/traffic-signals.json" });
@@ -551,29 +554,44 @@ function runCommand(command, commandArgs, stage) {
   }
 }
 
-function writeCesiumPreview(area) {
+function writeCesiumPreview(area, roadProvider) {
   ensureFile(area.outputs.packageManifest, "Published asset package manifest");
   ensureFile(area.outputs.packageTrafficSignals, "Published traffic signal anchors");
-  const lanePolygons = path.join(area.outputs.geojsonDir, "lane_polygons.geojson");
-  const network = path.join(area.outputs.geojsonDir, "network.json");
-  const intersectionSurface = path.join(area.outputs.geojsonDir, "intersection_surface.geojson");
-  ensureFile(lanePolygons, "Driving lane polygons");
-  ensureFile(network, "osm2streets network");
-  ensureFile(intersectionSurface, "Intersection surfaces");
-  // 在创建或覆盖任何 preview 产物前完成权威车道输入的解析与路线计算。
-  const vehicleRoute = buildPreviewVehicleRoute(area.input, lanePolygons, network, intersectionSurface);
+  let vehicleRoute = null;
+  const previewInputs = {
+    config: fileRecord(configPath),
+    osm: fileRecord(area.input),
+    previewCss: fileRecord(path.join(repoRoot, "scripts", "lib", "cesium-preview.css")),
+    previewJs: fileRecord(path.join(repoRoot, "scripts", "lib", "cesium-preview.js")),
+  };
+  if (roadProvider === "osm2streets") {
+    const lanePolygons = path.join(area.outputs.geojsonDir, "lane_polygons.geojson");
+    const network = path.join(area.outputs.geojsonDir, "network.json");
+    const intersectionSurface = path.join(area.outputs.geojsonDir, "intersection_surface.geojson");
+    ensureFile(lanePolygons, "Driving lane polygons");
+    ensureFile(network, "osm2streets network");
+    ensureFile(intersectionSurface, "Intersection surfaces");
+    vehicleRoute = buildPreviewVehicleRoute(area.input, lanePolygons, network, intersectionSurface);
+    Object.assign(previewInputs, {
+      lanePolygons: fileRecord(lanePolygons),
+      network: fileRecord(network),
+      intersectionSurface: fileRecord(intersectionSurface),
+    });
+  } else {
+    Object.assign(previewInputs, nativeRoadRecords(area));
+  }
   const htmlPath = area.outputs.cesiumPreview;
   const started = Date.now();
   const startedAt = new Date(started).toISOString();
   fs.mkdirSync(path.dirname(htmlPath), { recursive: true });
-  writeVehicleRoute(area, vehicleRoute);
+  if (vehicleRoute) writeVehicleRoute(area, vehicleRoute);
   const vehicleModelNames = writeVehicleModel(area);
   writeCesiumPreviewSupportFiles(path.dirname(htmlPath));
   const glbName = "package/manifest.json";
   const metadataName = "package/manifest.json";
-  const routeName = previewRelativePath(area.outputs.areaDir, area.outputs.vehicleRoute);
+  const routeName = vehicleRoute ? previewRelativePath(area.outputs.areaDir, area.outputs.vehicleRoute) : null;
   const vehicleModelName = previewRelativePath(area.outputs.areaDir, area.outputs.vehicleModel);
-  const descriptor = { routeName: previewRelativePath(area.outputs.areaDir, area.outputs.vehicleRoute), vehicleModelName: previewRelativePath(area.outputs.areaDir, area.outputs.vehicleModel), vehicleModelNames: vehicleModelNames.map((name) => `_preview/${name}`), trafficSignalsName: "package/runtime/traffic-signals.json", assets: [] };
+  const descriptor = { routeName, vehicleModelName: previewRelativePath(area.outputs.areaDir, area.outputs.vehicleModel), vehicleModelNames: vehicleModelNames.map((name) => `_preview/${name}`), trafficSignalsName: "package/runtime/traffic-signals.json", assets: [] };
   fs.mkdirSync(area.outputs.previewDir, { recursive: true });
   fs.writeFileSync(area.outputs.previewDescriptor, `${JSON.stringify(descriptor, null, 2)}\n`);
   fs.writeFileSync(htmlPath, cesiumPreviewHtml(glbName, metadataName, routeName, vehicleModelName, area.id, vehicleModelNames.map((name) => `_preview/${name}`), "package/runtime/traffic-signals.json", "_preview/descriptor.json"));
@@ -587,19 +605,13 @@ function writeCesiumPreview(area) {
     finishedAt: new Date(finished).toISOString(),
     durationMs: finished - started,
     inputs: {
-      config: fileRecord(configPath),
-      osm: fileRecord(area.input),
+      ...previewInputs,
       glb: fileRecord(area.outputs.packagePrimaryGlb),
       metadata: fileRecord(area.outputs.packageManifest),
-      lanePolygons: fileRecord(lanePolygons),
-      network: fileRecord(network),
-      intersectionSurface: fileRecord(intersectionSurface),
-      previewCss: fileRecord(path.join(repoRoot, "scripts", "lib", "cesium-preview.css")),
-      previewJs: fileRecord(path.join(repoRoot, "scripts", "lib", "cesium-preview.js")),
     },
     outputs: {
       cesiumPreview: fileRecord(area.outputs.cesiumPreview),
-      vehicleRoute: fileRecord(area.outputs.vehicleRoute),
+      vehicleRoute: optionalFileRecord(area.outputs.vehicleRoute),
       vehicleModel: fileRecord(area.outputs.vehicleModel),
       trafficSignals: fileRecord(area.outputs.packageTrafficSignals),
     },
diff --git a/scripts/lib/area-config.js b/scripts/lib/area-config.js
index 004c996..1859abf 100644
--- a/scripts/lib/area-config.js
+++ b/scripts/lib/area-config.js
@@ -85,7 +85,9 @@ function normalizeAreaConfig(raw, options = {}) {
     qgisApp: raw.qgisApp || (process.platform === "darwin" ? "/Applications/QGIS.app" : "/usr"),
     blenderApp: raw.blenderApp || (process.platform === "darwin" ? "/Applications/Blender.app" : "/usr/bin/blender"),
     stages: {
-      intermediates: raw.stages?.intermediates ?? raw.stages?.qgis ?? true,
+      // Native road compilation is the default. Legacy QGIS/osm2streets
+      // intermediates remain explicitly selectable for reference/debug work.
+      intermediates: raw.stages?.intermediates ?? raw.stages?.qgis ?? false,
       blender: raw.stages?.blender ?? true,
       cesium: raw.stages?.cesium ?? true,
       reimport: false,
@@ -121,7 +123,7 @@ function normalizeAreaConfig(raw, options = {}) {
     blender: {
       treeStyle: raw.blender?.treeStyle || "natural",
       officeOverrides: raw.blender?.officeOverrides || raw.blender?.office_overrides || "",
-      roadProvider: roadProviderOption(raw.blender?.roadProvider),
+      roadProvider: roadProviderOption(raw.blender?.roadProvider ?? "native"),
     },
     compress,
     budget,
diff --git a/scripts/lib/area-diagnostics.js b/scripts/lib/area-diagnostics.js
index 00faa13..da61eaf 100644
--- a/scripts/lib/area-diagnostics.js
+++ b/scripts/lib/area-diagnostics.js
@@ -323,13 +323,17 @@ function addEndpoint(map, ref) {
 }
 
 function artifactStatus(area) {
+  const native = area.blender.roadProvider === "native";
   const entries = [
-    ["GeoJSON dir", area.outputs.geojsonDir, true, "dir"],
-    ["GeoPackage", area.outputs.gpkg, true, "file"],
-    ["QGIS project", area.outputs.qgisProject, true, "file"],
-    ["QGIS preview", area.outputs.qgisPreview, true, "file"],
-    ["Traffic signal assemblies", area.outputs.trafficSignalAssemblies, true, "file"],
-    ["Traffic signal runtime", area.outputs.packageTrafficSignals, true, "file"],
+    ...(native ? [] : [
+      ["GeoJSON dir", area.outputs.geojsonDir, true, "dir"],
+      ["GeoPackage", area.outputs.gpkg, true, "file"],
+      ["QGIS project", area.outputs.qgisProject, true, "file"],
+      ["QGIS preview", area.outputs.qgisPreview, true, "file"],
+      ["Traffic signal assemblies", area.outputs.trafficSignalAssemblies, true, "file"],
+    ]),
+    ["Native road directory", area.outputs.nativeRoadDir, native, "dir"],
+    ["Traffic signal runtime", native ? path.join(area.outputs.nativeRoadDir, "traffic-signals.json") : area.outputs.packageTrafficSignals, true, "file"],
     ["Blend scene", area.outputs.blend, true, "file"],
     ["Render PNG", area.outputs.render, true, "file"],
     ["Package manifest", area.outputs.packageManifest, true, "file"],
@@ -373,6 +377,7 @@ function metadataSummary(file, warnings) {
 }
 
 function stageManifestStatus(area, configPath = null) {
+  const native = area.blender.roadProvider === "native";
   const compressionComplete = fs.existsSync(stageManifestPath(area, "compress"));
   const reimportManifest = stageManifestPath(area, "reimport");
   const hasReimportManifest = fs.existsSync(reimportManifest);
@@ -430,10 +435,12 @@ function stageManifestStatus(area, configPath = null) {
       inputs: {
         ...(configPath ? { config: configPath } : {}),
         osm: area.input,
-        geojsonDir: area.outputs.geojsonDir,
-        ...sceneGeojsonFiles(area),
-        trafficSignalAssemblies: area.outputs.trafficSignalAssemblies,
-        trafficSignals: area.outputs.packageTrafficSignals,
+        ...(native ? nativeRoadRecords(area) : {
+          geojsonDir: area.outputs.geojsonDir,
+          ...sceneGeojsonFiles(area),
+          trafficSignalAssemblies: area.outputs.trafficSignalAssemblies,
+          trafficSignals: area.outputs.packageTrafficSignals,
+        }),
       },
       outputs: {
         blend: area.outputs.blend,
@@ -461,18 +468,20 @@ function stageManifestStatus(area, configPath = null) {
           glb: area.outputs.glb,
           metadata: area.outputs.metadata,
         }),
-        lanePolygons: path.join(area.outputs.geojsonDir, "lane_polygons.geojson"),
-        network: path.join(area.outputs.geojsonDir, "network.json"),
-        intersectionSurface: path.join(area.outputs.geojsonDir, "intersection_surface.geojson"),
+        ...(native ? nativeRoadRecords(area) : {
+          lanePolygons: path.join(area.outputs.geojsonDir, "lane_polygons.geojson"),
+          network: path.join(area.outputs.geojsonDir, "network.json"),
+          intersectionSurface: path.join(area.outputs.geojsonDir, "intersection_surface.geojson"),
+        }),
         previewCss: path.join(path.resolve(__dirname, ".."), "lib", "cesium-preview.css"),
         previewJs: path.join(path.resolve(__dirname, ".."), "lib", "cesium-preview.js"),
       },
       outputs: compressionComplete ? {
-        vehicleRoute: area.outputs.vehicleRoute,
+        vehicleRoute: native ? optionalExpectedFile(area.outputs.vehicleRoute) : area.outputs.vehicleRoute,
         vehicleModel: area.outputs.vehicleModel,
       } : {
         cesiumPreview: area.outputs.cesiumPreview,
-        vehicleRoute: area.outputs.vehicleRoute,
+        vehicleRoute: native ? optionalExpectedFile(area.outputs.vehicleRoute) : area.outputs.vehicleRoute,
         vehicleModel: area.outputs.vehicleModel,
       },
     },
@@ -597,6 +606,24 @@ function sceneGeojsonFiles(area) {
   return files;
 }
 
+function nativeRoadRecords(area) {
+  const root = path.join(area.outputs.nativeRoadDir, "layers");
+  return {
+    nativeRoadCompiled: path.join(area.outputs.nativeRoadDir, "compiled.json"),
+    nativeRoadSignals: path.join(area.outputs.nativeRoadDir, "traffic-signals.json"),
+    nativeRoadSurface: path.join(root, "road_surface.geojson"),
+    nativeEdgeLines: path.join(root, "edge_lines.geojson"),
+    nativeIntersectionSurface: path.join(root, "intersection_surface.geojson"),
+    nativeSidewalkSurface: path.join(root, "sidewalk_surface.geojson"),
+    nativeLaneSeparators: path.join(root, "lane_separators.geojson"),
+    nativeCenterLines: path.join(root, "center_lines.geojson"),
+    nativeDirectionArrows: path.join(root, "direction_arrows.geojson"),
+    nativeTurnArrows: path.join(root, "turn_arrows.geojson"),
+    nativeCrosswalks: path.join(root, "crosswalks.geojson"),
+    nativeVehicleStopLines: path.join(root, "vehicle_stop_lines.geojson"),
+  };
+}
+
 function collectWarnings(area, osm, artifacts, manifests, glb, metadata) {
   const warnings = [];
   if (!osm.bounds) warnings.push("OSM has no valid <bounds>; scene extent may be wrong.");
diff --git a/scripts/lib/area-preview.js b/scripts/lib/area-preview.js
index 4522338..28bcce8 100644
--- a/scripts/lib/area-preview.js
+++ b/scripts/lib/area-preview.js
@@ -124,14 +124,14 @@ function escapeScriptJson(value) {
 }
 
 function previewSummary(area) {
-  const route = JSON.parse(fs.readFileSync(area.outputs.vehicleRoute, "utf8"));
+  const route = fs.existsSync(area.outputs.vehicleRoute) ? JSON.parse(fs.readFileSync(area.outputs.vehicleRoute, "utf8")) : null;
   return {
     glbName: "package/manifest.json",
     metadataName: "package/manifest.json",
-    routeName: path.relative(area.outputs.areaDir, area.outputs.vehicleRoute).split(path.sep).join("/"),
+    routeName: route ? path.relative(area.outputs.areaDir, area.outputs.vehicleRoute).split(path.sep).join("/") : null,
     vehicleModelName: path.relative(area.outputs.areaDir, area.outputs.vehicleModel).split(path.sep).join("/"),
     trafficSignalsName: "package/runtime/traffic-signals.json",
-    routeSegments: Array.isArray(route.segments) ? route.segments.length : null,
+    routeSegments: Array.isArray(route?.segments) ? route.segments.length : null,
   };
 }
 
diff --git a/scripts/lib/build-stages.js b/scripts/lib/build-stages.js
index 3fcb40c..72aba4e 100644
--- a/scripts/lib/build-stages.js
+++ b/scripts/lib/build-stages.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const STAGES = [
-  { id: "intermediates", label: "OSM / QGIS intermediates", description: "Rebuild GeoJSON and GeoPackage from OSM" },
+  { id: "intermediates", label: "Legacy QGIS intermediates", description: "Explicit legacy osm2streets/QGIS reference build" },
   { id: "reimport", label: "Reimport QGIS edits", description: "Copy GeoPackage layers back to GeoJSON" },
   { id: "blender", label: "Blender scene", description: "Generate the editable scene and render" },
   { id: "cesium", label: "Cesium export", description: "Export static package staging assets" },
@@ -11,7 +11,7 @@ const STAGES = [
 ];
 
 const ALIASES = {
-  all: ["intermediates", "blender", "cesium", "compress", "package", "preview"],
+  all: ["blender", "cesium", "compress", "package", "preview"],
   qgis: ["intermediates"], osm2streets: ["intermediates"], geojson: ["intermediates"], intermediate: ["intermediates"],
   intermediates: ["intermediates"], reimport: ["reimport"], gpkg: ["reimport"], blender: ["blender"], scene: ["blender"],
   cesium: ["cesium"], glb: ["cesium"], preview: ["preview"], html: ["preview"], cesiumPreview: ["preview"],
diff --git a/scripts/lib/cesium-preview.js b/scripts/lib/cesium-preview.js
index ded3754..f87aafb 100644
--- a/scripts/lib/cesium-preview.js
+++ b/scripts/lib/cesium-preview.js
@@ -88,6 +88,7 @@
   // The route file is an extra on top of the scene, not a precondition for it.
   // A missing or unreadable route costs the cruise controls, not the preview.
   async function fetchOptionalJson(url) {
+    if (!url) return null;
     try {
       return await fetchJson(url);
     } catch (error) {
diff --git a/scripts/test-asset-budgets.js b/scripts/test-asset-budgets.js
index f2e4d21..f494df4 100644
--- a/scripts/test-asset-budgets.js
+++ b/scripts/test-asset-budgets.js
@@ -17,6 +17,9 @@ assert.match(qgisBuildSource, /QgsFieldConstraints\.ConstraintNotNull/);
 assert.doesNotMatch(qgisBuildSource, /setFieldConstraint\(index, 1\)/);
 assert.match(areaBuildSource, /exportCesium\(area, roadProvider\)/);
 assert.match(areaBuildSource, /if \(roadProvider === "osm2streets"\) \{\n    exporterArgs\.splice/);
+assert.match(areaBuildSource, /if \(roadProvider === "osm2streets"\) \{[\s\S]*?buildPreviewVehicleRoute/);
+assert.match(areaBuildSource, /Object\.assign\(previewInputs, nativeRoadRecords\(area\)\)/);
+assert.match(areaBuildSource, /vehicleRoute: optionalFileRecord\(area\.outputs\.vehicleRoute\)/);
 
 const gltf = {
   nodes: [
@@ -54,7 +57,8 @@ assert.equal(
   path.join(tempDir, "test-area", "osm2streets_web_out", "traffic_signal_assemblies.geojson"),
 );
 assert.equal(normalizeAreaConfig({ ...base, budget: { nodes: 800 } }).budget.glbNodes, 800);
-assert.equal(normalizeAreaConfig(base).blender.roadProvider, "osm2streets");
+assert.equal(normalizeAreaConfig(base).stages.intermediates, false);
+assert.equal(normalizeAreaConfig(base).blender.roadProvider, "native");
 assert.equal(normalizeAreaConfig({ ...base, blender: { roadProvider: "native" } }).blender.roadProvider, "native");
 assert.throws(
   () => normalizeAreaConfig({ ...base, blender: { roadProvider: "other" } }),
@@ -78,8 +82,9 @@ assert.equal(
 );
 
 const configPath = path.join(tempDir, "area.json");
-fs.writeFileSync(configPath, `${JSON.stringify(base)}\n`);
-const area = normalizeAreaConfig(base);
+const legacyBase = { ...base, blender: { roadProvider: "osm2streets" } };
+fs.writeFileSync(configPath, `${JSON.stringify(legacyBase)}\n`);
+const area = normalizeAreaConfig(legacyBase);
 assert.equal(area.stages.compress, true);
 assert.equal("compressedGlb" in area.outputs, false);
 assert.equal("compressedMetadata" in area.outputs, false);
diff --git a/scripts/test-build-stages.js b/scripts/test-build-stages.js
index e097466..fb126c2 100644
--- a/scripts/test-build-stages.js
+++ b/scripts/test-build-stages.js
@@ -4,7 +4,7 @@ const assert = require("assert");
 const fs = require("fs");
 const { resolveStages, canonicalStages } = require("./lib/build-stages");
 assert.deepEqual(canonicalStages(resolveStages({}, ["compress", "blender", "preview"])), ["blender", "compress", "preview"]);
-assert.deepEqual(canonicalStages(resolveStages({}, ["all"])), ["intermediates", "blender", "cesium", "compress", "package", "preview"]);
+assert.deepEqual(canonicalStages(resolveStages({}, ["all"])), ["blender", "cesium", "compress", "package", "preview"]);
 assert.deepEqual(canonicalStages(resolveStages({ intermediates: true, blender: true, cesium: true, compress: true, package: true })), ["intermediates", "blender", "cesium", "compress", "package"]);
 assert.throws(() => resolveStages({}, ["intermediates", "reimport"]), /mutually exclusive/);
 const buildAreaSource = fs.readFileSync(require("path").join(__dirname, "build-area.js"), "utf8");