feat(preview): add low poly vehicle library

.trellis/spec/blender/asset-generation.md

@@ -259,6 +259,17 @@ tilt_y       = TILT_JITTER * math.cos(index * 0.927295)
 | 靠调 `FOLIAGE_EMISSION` 提亮植被 | 用错了旋钮，该调 albedo gain |
 | 在 `MATERIALS` 中间插入条目 | GLB 材质索引整体平移 |
 
+## 第三方资产导入的源文件边界
+
+第三方 Blend 只属于一次性入库工具的输入，不能成为 `build:area` 或 Cesium 预览的运行时依赖。
+完成拆分后，仓库必须包含可直接消费的 glTF/bin、共享贴图、manifest 和人工预览；原始下载文件可
+以删除。导入工具应将源文件路径作为显式 `--source` 参数，manifest 最多保留源文件名作溯源，
+不能写死用户 Downloads 目录。
+
+删除原始文件前必须确认入库资产已通过结构验证和人工预览；删除后若需重新导入，必须重新取得
+同一 Blend 与其外部贴图。`blender/tools/split_lowpoly_cars.py` 是这一约定的实例，不参与区域
+构建阶段。
+
 ---
 
 ## 相关

.trellis/tasks/08-05-lowpoly-cars-assets/check.jsonl

@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}

.trellis/tasks/08-05-lowpoly-cars-assets/design.md

@@ -0,0 +1,54 @@
+# 设计：LowPoly Cars 资产库
+
+## 边界与目录
+
+本任务独立于区域构建和 Cesium 预览。新增目录
+`assets/models/custom/lowpoly_cars/`，其内部结构与 Shapespark 植物包一致：
+
+```text
+lowpoly_cars/
+  manifest.json
+  index.html
+  textures/
+  <vehicle-id>/model.gltf
+  <vehicle-id>/model.bin
+  <vehicle-id>/preview.png
+```
+
+源 `.blend` 保留在用户 Downloads，不复制入仓库；`manifest.json` 保存源文件名与根对象名，
+以便可追溯而不引入二进制源文件。
+
+## 拆分与规范化
+
+新 Blender 工具以 Empty 根节点和其全部后代 mesh 作为一辆车。根节点名是稳定初始 ID：
+`car_a01_002`、`truck_a01_001` 等。名称重复的车辆保留全部条目，不依据几何统计猜测合并。
+
+导出前把每辆车的根节点变换 bake 到其后代网格，再把局部原点置于车辆的水平中心和最低接地点。
+规范化的预览坐标为 X 前进、Y 向上、Z 横向；若源根节点的朝向不符合它，工具按对象族显式
+变换并由渲染缩略图复核。不能依赖源文件中用于陈列的全局坐标、`0.001` 缩放或 90°/180°旋转。
+
+保留同一辆车的 mesh 分件与材质槽，避免为图库的便利合并导致窗、轮胎等材质丢失。图像依赖
+集中复制到 `textures/`，glTF 以相对路径引用，重复车款不能复制同一张贴图。
+
+## 产物与预览
+
+工具为每辆车导出 glTF/bin，使用隔离的三点布光、地面阴影与固定透视相机输出
+`preview.png`。`index.html` 只消费 manifest，响应式显示缩略图、ID、类别、三角面数、尺寸和
+材质；它不依赖 Cesium、Node 打包或区域输出，通过 HTTP 直接查看。
+
+`manifest.json` 的每项至少包含 `id`、`name`、`category`、`sourceRoot`、`model`、`bin`、
+`preview`，以及 `metrics.vertices`、`metrics.triangles`、`metrics.dimensions`、
+`metrics.materials`。`category` 取 `car`、`truck` 或 `tractor`。
+
+## 风险与回退
+
+Blender 的沙箱内加载会崩溃，因此导出、渲染和检查仅通过受批准的沙箱外 Blender 调用。若
+某一根节点导出失败，工具记录错误并继续其余资产；manifest 只收录有效产物，失败根节点写入
+报告。删除 `lowpoly_cars/` 不影响任何当前构建阶段或 Cesium 巡航。
+
+## Cesium 候选集
+
+候选集固定为 `car_a01_002`、`car_a02_002`、`car_a03_001`，以及按稳定 ID 排序的前三辆
+卡车 `truck_a01_001`、`truck_a02_001`、`truck_a03_001`。预览构建把这六个 glTF/bin 与一张
+共享 512px 贴图复制到区域输出目录并改写其 image URI；浏览器页面加载时从文件名列表随机选
+一项，所有巡航实体在本页使用相同模型。这样构建产物保持确定，随机性只属于用户可见的会话。

.trellis/tasks/08-05-lowpoly-cars-assets/implement.jsonl

@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}

.trellis/tasks/08-05-lowpoly-cars-assets/implement.md

@@ -0,0 +1,27 @@
+# 实施计划：LowPoly Cars 资产库
+
+1. 在 `blender/tools/` 增加可重复执行的拆分/导出工具，读取指定 `.blend`，枚举命名 Empty
+   根节点，bake 变换、规范化坐标并分别导出车辆。
+2. 让工具生成共享贴图目录、逐车 glTF/bin、缩略图、manifest 与静态图库 HTML；输出排序必须
+   按稳定 ID，避免重复运行产生无关差异。
+3. 为导出结果提供轻量结构检查：验证 manifest 路径存在、ID 唯一、几何指标为正、模型和缩略图
+   可读取；对源根节点与导出条目数量做对账。
+4. 在沙箱外运行导出与缩略图渲染，目检图库中的普通车、卡车和拖拉机，核对朝向、落地与比例。
+5. 运行 Python/Node 语法检查和现有 preview 测试，确认不触及 `vehicle-model.js`、路线 JSON 或
+   Cesium 默认预览；记录验证结果。
+6. 验收后提交资产库、工具、来源说明与必要的代码规范；不改当前默认巡航模型。
+
+## 验证
+
+```bash
+blender --factory-startup --background --python blender/tools/<tool>.py -- --source <blend> --output assets/models/custom/lowpoly_cars
+python3 blender/tools/<tool>.py --verify assets/models/custom/lowpoly_cars
+node --check scripts/lib/vehicle-model.js
+npm run test:preview-assets
+git diff --check
+```
+
+## 回滚
+
+本任务只新增独立资产库和工具。若某项导出或方向不合格，删除该新增目录和工具即可；当前区域
+构建和 Cesium 预览没有依赖它们。

.trellis/tasks/08-05-lowpoly-cars-assets/prd.md

@@ -0,0 +1,53 @@
+# 拆分 LowPoly Cars 车辆资产
+
+## Goal
+
+将用户下载的 `011.+LowPoly_Cars_01_blend.blend` 拆分为可独立检查、可被后续
+Cesium 车辆预览复用的低模车辆资产库；沿用 Shapespark 植物包的资产目录、清单与
+浏览器预览体验。
+
+## Confirmed Facts
+
+- 源文件位于 `/Users/que01/Downloads/011.+LowPoly_Cars_01_blend.blend`，为 Blender
+  3.0、64 位小端格式，约 25 MB；不应直接作为仓库产物引用。
+- 当前 Blender 4.5.12 LTS 在沙箱中加载会崩溃；在沙箱外可稳定读取，故拆分和渲染应通过
+  沙箱外 Blender 调用完成。
+- 源文件有 12 个可导出 Empty 根节点：5 个普通车条目（其中 `car_a01`、`car_a02` 各有两份
+  同名变体）、4 个卡车、3 个拖拉机；每项由 11 到 19 个 mesh 组成。
+- 根节点保存了展示排布用的 `0.001` 缩放与 90°/180°旋转。拆分必须应用这些层级变换，统一
+  比例、地面基线和车辆前进轴，不能将源文件世界坐标原样导出。
+- 主体使用共享 `carmaterial`（含 base-color 图和 normal map），拆分后应共用贴图，不复制到
+  每一个车辆目录。
+- 植物包位于 `assets/models/custom/shapespark_plants/`：每个资产拥有
+  `model.gltf`、`model.bin`、`preview.png`，共享贴图放 `textures/`，并以
+  `manifest.json` 和 `index.html` 提供机器与人工检查入口。
+- 已完成的车辆连续路线系统读取预览车辆 glTF；新资产库在验收前不得破坏该默认车辆或
+  现有路线播放。
+
+## Requirements
+
+1. 稳定读取源 `.blend`，记录其集合、对象、材质、几何指标、坐标朝向和许可/来源信息。
+2. 按可独立使用的车辆变体拆分为 glTF 资产，保留正确比例、轮胎落地基线、前进朝向与
+   原始材质语义；共享贴图不得为每辆车重复复制。
+3. 在 `assets/models/custom/` 下创建与植物包一致的清晰目录、JSON manifest 与简洁的
+   HTML 图库预览；每辆车显示缩略图、三角面数、尺寸与材质信息。
+4. 预览页必须可通过本地 HTTP 查看，不依赖主场景或 QGIS；缩略图应能帮助比较车款、颜色
+   和比例。
+5. 新库经过 Blender/glTF 结构检查；从普通车中固定选 3 个、从卡车中选前 3 个组成候选集，
+   Cesium 每次打开预览时从该 6 个模型随机选一辆作为巡航车辆。
+
+## Acceptance Criteria
+
+- [ ] 能稳定枚举源文件内的可导出车辆，并把每个产物与源对象/集合对应起来。
+- [ ] 每个可用车辆有独立 `model.gltf`/二进制数据、预览图与 manifest 条目；预览图和 HTML
+      能正确加载。
+- [ ] manifest 为每项记录稳定 ID、名称、来源、几何指标、尺寸、材质和相对路径。
+- [ ] 人工查看图库可比较全部导出的车辆；没有重复贴图、明显错误的坐标轴或悬空/埋地车轮。
+- [ ] 现有目标区域的 Cesium 巡航预览仍可生成和播放。
+- [ ] 目标区域预览目录包含选定的 6 个车辆模型与一张共享贴图；页面刷新会从候选集随机选车。
+
+## Out of Scope
+
+- 不在本任务中制作车辆动画、转向轮、交通行为、LOD 或性能压缩策略。
+- 不修改 QGIS 工程、道路生成或上一轮已经确认的车辆连续路线逻辑。
+- 不引入车辆动画、逐车随机分配、性能压缩或车辆选择控件；本轮只在页面加载时随机确定一种车。

.trellis/tasks/08-05-lowpoly-cars-assets/task.json

@@ -0,0 +1,26 @@
+{
+  "id": "lowpoly-cars-assets",
+  "name": "lowpoly-cars-assets",
+  "title": "拆分 LowPoly Cars 车辆资产",
+  "description": "",
+  "status": "in_progress",
+  "dev_type": null,
+  "scope": null,
+  "package": null,
+  "priority": "P2",
+  "creator": "dingkang",
+  "assignee": "dingkang",
+  "createdAt": "2026-08-05",
+  "completedAt": null,
+  "branch": null,
+  "base_branch": "main",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": null,
+  "relatedFiles": [],
+  "notes": "",
+  "meta": {}
+}

assets/models/SOURCES.md

@@ -19,3 +19,21 @@
 旧的 SpeedTree apple、Lyrog fattree、Poly Haven `shrub_02`、原始高模
 `custom/bush` 和 rejected `custom/bush_low` 已删除。相关实验结论保留在
 `docs/changelog.md` 和归档 Trellis 任务中。
+
+## LowPoly Cars
+
+`assets/models/custom/lowpoly_cars/` 是从用户本地下载的
+`011.+LowPoly_Cars_01_blend.blend` 拆分出的车辆图库。目录结构与植物包一致：每辆车
+拥有 `model.gltf`、`model.bin` 与 `preview.png`；全部资产共用
+`textures/color_512x512.jpg`，以保留颜色图集中的各车型车漆区域。
+
+`manifest.json` 记录源 Empty 根节点、分类、尺寸、顶点/三角面数和相对文件路径，
+`index.html` 用于人工选择车款。源文件许可证尚未确认；在重新分发资产前必须核对原始下载
+页面的许可。
+
+拆分由 `blender/tools/split_lowpoly_cars.py` 执行。该工具只读取源 Blend 与指定贴图，
+不会接入或替换当前 Cesium 巡航车辆。
+
+区域构建**不依赖** Downloads 中的原始 `.blend`：它只读取本目录已提交的 glTF/bin/贴图。
+因此原始 Blend 可以在验收后删除；代价是日后不能从零重跑该导入脚本，除非重新取得同一源文件
+与颜色贴图。

assets/models/custom/lowpoly_cars/index.html

@@ -0,0 +1,13 @@
+<!doctype html><meta charset="utf-8"><title>LowPoly Cars</title>
+<style>body{margin:24px;font:14px system-ui,sans-serif;background:#edf1f3;color:#16212a}main{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}article{background:#fff;border:1px solid #cbd5db;border-radius:6px;padding:10px}img{width:100%;aspect-ratio:1;object-fit:contain;background:#20282e}h2{font-size:15px;margin:8px 0 4px}p{margin:3px 0;color:#4a5862}</style><main><article><img src="car_a01_002/preview.png" alt="Car A01 002"><h2>Car A01 002</h2><p>car · 4,574 tris</p><p>5.3661 x 2.2731 x 2.1082 m</p><p>carmaterial</p></article>
+<article><img src="car_a01_003/preview.png" alt="Car A01 003"><h2>Car A01 003</h2><p>car · 4,574 tris</p><p>5.3661 x 2.2731 x 2.1082 m</p><p>carmaterial</p></article>
+<article><img src="car_a02_002/preview.png" alt="Car A02 002"><h2>Car A02 002</h2><p>car · 5,898 tris</p><p>5.3727 x 2.3141 x 2.1082 m</p><p>carmaterial</p></article>
+<article><img src="car_a02_003/preview.png" alt="Car A02 003"><h2>Car A02 003</h2><p>car · 5,898 tris</p><p>5.3727 x 2.3141 x 2.1082 m</p><p>carmaterial</p></article>
+<article><img src="car_a03_001/preview.png" alt="Car A03 001"><h2>Car A03 001</h2><p>car · 14,028 tris</p><p>9.6993 x 2.7325 x 2.1082 m</p><p>carmaterial</p></article>
+<article><img src="tractor_a01_001/preview.png" alt="Tractor A01 001"><h2>Tractor A01 001</h2><p>tractor · 3,899 tris</p><p>4.3862 x 2.5279 x 3.04 m</p><p>carmaterial</p></article>
+<article><img src="tractor_a02_001/preview.png" alt="Tractor A02 001"><h2>Tractor A02 001</h2><p>tractor · 4,295 tris</p><p>5.894 x 2.8004 x 3.0523 m</p><p>carmaterial</p></article>
+<article><img src="tractor_a03_001/preview.png" alt="Tractor A03 001"><h2>Tractor A03 001</h2><p>tractor · 12,767 tris</p><p>10.4554 x 2.7708 x 3.04 m</p><p>carmaterial</p></article>
+<article><img src="truck_a01_001/preview.png" alt="Truck A01 001"><h2>Truck A01 001</h2><p>truck · 8,724 tris</p><p>14.7667 x 3.288 x 4.5493 m</p><p>carmaterial</p></article>
+<article><img src="truck_a02_001/preview.png" alt="Truck A02 001"><h2>Truck A02 001</h2><p>truck · 8,444 tris</p><p>12.1239 x 3.2881 x 4.5493 m</p><p>carmaterial</p></article>
+<article><img src="truck_a03_001/preview.png" alt="Truck A03 001"><h2>Truck A03 001</h2><p>truck · 12,172 tris</p><p>12.1625 x 3.4661 x 4.0701 m</p><p>carmaterial</p></article>
+<article><img src="truck_a04_001/preview.png" alt="Truck A04 001"><h2>Truck A04 001</h2><p>truck · 13,127 tris</p><p>12.1068 x 3.4692 x 4.0701 m</p><p>carmaterial</p></article></main>

assets/models/custom/lowpoly_cars/manifest.json

@@ -0,0 +1,260 @@
+{
+  "source": "011.+LowPoly_Cars_01_blend.blend",
+  "license": "Unknown; verify the original download license before redistribution.",
+  "texture": "textures/color_512x512.jpg",
+  "layout": "Each asset has model.gltf/model.bin/preview.png; the 512px color texture is shared in textures/.",
+  "assets": [
+    {
+      "id": "car_a01_002",
+      "name": "Car A01 002",
+      "category": "car",
+      "sourceRoot": "car_a01_002",
+      "model": "car_a01_002/model.gltf",
+      "bin": "car_a01_002/model.bin",
+      "preview": "car_a01_002/preview.png",
+      "metrics": {
+        "vertices": 2526,
+        "triangles": 4574,
+        "dimensions": [
+          5.3661,
+          2.2731,
+          2.1082
+        ],
+        "materials": [
+          "carmaterial"
+        ]
+      }
+    },
+    {
+      "id": "car_a01_003",
+      "name": "Car A01 003",
+      "category": "car",
+      "sourceRoot": "car_a01_003",
+      "model": "car_a01_003/model.gltf",
+      "bin": "car_a01_003/model.bin",
+      "preview": "car_a01_003/preview.png",
+      "metrics": {
+        "vertices": 2526,
+        "triangles": 4574,
+        "dimensions": [
+          5.3661,
+          2.2731,
+          2.1082
+        ],
+        "materials": [
+          "carmaterial"
+        ]
+      }
+    },
+    {
+      "id": "car_a02_002",
+      "name": "Car A02 002",
+      "category": "car",
+      "sourceRoot": "car_a02_002",
+      "model": "car_a02_002/model.gltf",
+      "bin": "car_a02_002/model.bin",
+      "preview": "car_a02_002/preview.png",
+      "metrics": {
+        "vertices": 3426,
+        "triangles": 5898,
+        "dimensions": [
+          5.3727,
+          2.3141,
+          2.1082
+        ],
+        "materials": [
+          "carmaterial"
+        ]
+      }
+    },
+    {
+      "id": "car_a02_003",
+      "name": "Car A02 003",
+      "category": "car",
+      "sourceRoot": "car_a02_003",
+      "model": "car_a02_003/model.gltf",
+      "bin": "car_a02_003/model.bin",
+      "preview": "car_a02_003/preview.png",
+      "metrics": {
+        "vertices": 3426,
+        "triangles": 5898,
+        "dimensions": [
+          5.3727,
+          2.3141,
+          2.1082
+        ],
+        "materials": [
+          "carmaterial"
+        ]
+      }
+    },
+    {
+      "id": "car_a03_001",
+      "name": "Car A03 001",
+      "category": "car",
+      "sourceRoot": "car_a03_001",
+      "model": "car_a03_001/model.gltf",
+      "bin": "car_a03_001/model.bin",
+      "preview": "car_a03_001/preview.png",
+      "metrics": {
+        "vertices": 9401,
+        "triangles": 14028,
+        "dimensions": [
+          9.6993,
+          2.7325,
+          2.1082
+        ],
+        "materials": [
+          "carmaterial"
+        ]
+      }
+    },
+    {
+      "id": "tractor_a01_001",
+      "name": "Tractor A01 001",
+      "category": "tractor",
+      "sourceRoot": "tractor_a01_001",
+      "model": "tractor_a01_001/model.gltf",
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+      "buffer": 0,
+      "byteLength": 25680,
+      "byteOffset": 68380,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 25680,
+      "byteOffset": 94060,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 17120,
+      "byteOffset": 119740,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 8016,
+      "byteOffset": 136860,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteLength": 26496,
+      "byteOffset": 144876,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 26496,
+      "byteOffset": 171372,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 17664,
+      "byteOffset": 197868,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 7440,
+      "byteOffset": 215532,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteLength": 672,
+      "byteOffset": 222972,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 672,
+      "byteOffset": 223644,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 448,
+      "byteOffset": 224316,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 168,
+      "byteOffset": 224764,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteLength": 480,
+      "byteOffset": 224932,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 480,
+      "byteOffset": 225412,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 320,
+      "byteOffset": 225892,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 120,
+      "byteOffset": 226212,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteLength": 3360,
+      "byteOffset": 226332,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 3360,
+      "byteOffset": 229692,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 2240,
+      "byteOffset": 233052,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 792,
+      "byteOffset": 235292,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteLength": 2304,
+      "byteOffset": 236084,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 2304,
+      "byteOffset": 238388,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 1536,
+      "byteOffset": 240692,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteLength": 528,
+      "byteOffset": 242228,
+      "target": 34963
+    }
+  ],
+  "samplers": [
+    {
+      "magFilter": 9729,
+      "minFilter": 9987
+    }
+  ],
+  "buffers": [
+    {
+      "byteLength": 242756,
+      "uri": "model.bin"
+    }
+  ]
+}

blender/tools/split_lowpoly_cars.py

@@ -0,0 +1,334 @@
+#!/usr/bin/env python3
+"""Split the downloaded LowPoly Cars Blend into a browsable, reusable asset kit.
+
+Run through Blender because the source Blend is not safe to open in the sandbox:
+  blender --factory-startup --background --python blender/tools/split_lowpoly_cars.py -- \
+    --source /Users/que01/Downloads/011.+LowPoly_Cars_01_blend.blend \
+    --textures /Users/que01/Downloads/textures111 \
+    --output assets/models/custom/lowpoly_cars
+"""
+
+import json
+import math
+import os
+import shutil
+import sys
+
+import bpy
+from mathutils import Matrix, Vector
+
+
+TEXTURE_NAME = "color_512x512.jpg"
+PREVIEW_SIZE = 640
+CESIUM_ALBEDO_GAIN = 2.6
+
+
+def cli_args():
+    argv = sys.argv[sys.argv.index("--") + 1:] if "--" in sys.argv else []
+    values = {}
+    while argv:
+        key = argv.pop(0)
+        if not key.startswith("--"):
+            raise RuntimeError("Expected a --key argument, got " + key)
+        if not argv:
+            raise RuntimeError("Missing value for " + key)
+        values[key[2:]] = argv.pop(0)
+    return values
+
+
+def require_file(path, label):
+    if not path or not os.path.isfile(path):
+        raise RuntimeError(label + " does not exist: " + str(path))
+
+
+def category_for(name):
+    return name.split("_", 1)[0]
+
+
+def roots():
+    return sorted(
+        (obj for obj in bpy.data.objects if obj.type == "EMPTY" and obj.children),
+        key=lambda obj: obj.name,
+    )
+
+
+def descendants(root):
+    found = []
+    pending = list(root.children)
+    while pending:
+        obj = pending.pop()
+        found.append(obj)
+        pending.extend(obj.children)
+    return [obj for obj in found if obj.type == "MESH"]
+
+
+def world_vertices(meshes):
+    return [obj.matrix_world @ vertex.co for obj in meshes for vertex in obj.data.vertices]
+
+
+def longitudinal_angle(points):
+    """Align the longest ground-plane PCA axis with +X for consistent previews."""
+    mean_x = sum(point.x for point in points) / len(points)
+    mean_y = sum(point.y for point in points) / len(points)
+    xx = sum((point.x - mean_x) ** 2 for point in points)
+    yy = sum((point.y - mean_y) ** 2 for point in points)
+    xy = sum((point.x - mean_x) * (point.y - mean_y) for point in points)
+    return 0.5 * math.atan2(2.0 * xy, xx - yy)
+
+
+def bounds(objects):
+    points = [obj.matrix_world @ Vector(corner) for obj in objects for corner in obj.bound_box]
+    lower = Vector(tuple(min(point[axis] for point in points) for axis in range(3)))
+    upper = Vector(tuple(max(point[axis] for point in points) for axis in range(3)))
+    return lower, upper
+
+
+def reset_temp_collection(collection):
+    for obj in list(collection.objects):
+        mesh = obj.data if obj.type == "MESH" else None
+        bpy.data.objects.remove(obj, do_unlink=True)
+        if mesh and mesh.users == 0:
+            bpy.data.meshes.remove(mesh)
+
+
+def make_normalized_objects(root, collection):
+    source_meshes = descendants(root)
+    points = world_vertices(source_meshes)
+    if not points:
+        raise RuntimeError(root.name + " has no mesh descendants")
+    lower = Vector(tuple(min(point[axis] for point in points) for axis in range(3)))
+    upper = Vector(tuple(max(point[axis] for point in points) for axis in range(3)))
+    center = Vector(((lower.x + upper.x) / 2.0, (lower.y + upper.y) / 2.0, lower.z))
+    rotation = Matrix.Rotation(-longitudinal_angle(points), 4, "Z")
+    transform = rotation @ Matrix.Translation(-center)
+    result = []
+    for source in source_meshes:
+        mesh = source.data.copy()
+        mesh.transform(transform @ source.matrix_world)
+        obj = bpy.data.objects.new(source.name, mesh)
+        collection.objects.link(obj)
+        for material in source.data.materials:
+            mesh.materials.append(material)
+        result.append(obj)
+    return result
+
+
+def select_only(objects):
+    bpy.ops.object.select_all(action="DESELECT")
+    for obj in objects:
+        obj.select_set(True)
+    bpy.context.view_layer.objects.active = objects[0]
+
+
+def bake_cesium_texture(texture_path, output_path):
+    """Bake the Cesium albedo gain into the shared JPEG pixels."""
+    source = bpy.data.images.load(texture_path, check_existing=False)
+    source.name = "LowPolyCarsSourceTexture"
+    result = bpy.data.images.new("LowPolyCarsCesiumTexture", source.size[0], source.size[1], alpha=False)
+    pixels = list(source.pixels)
+    for index in range(0, len(pixels), 4):
+        pixels[index] = min(1.0, pixels[index] * CESIUM_ALBEDO_GAIN)
+        pixels[index + 1] = min(1.0, pixels[index + 1] * CESIUM_ALBEDO_GAIN)
+        pixels[index + 2] = min(1.0, pixels[index + 2] * CESIUM_ALBEDO_GAIN)
+        pixels[index + 3] = 1.0
+    result.pixels = pixels
+    result.filepath_raw = output_path
+    result.file_format = "JPEG"
+    result.save()
+    return result
+
+
+def setup_material_texture(image):
+    # The source Blend retains a broken relative image datablock. Loading a
+    # fresh datablock, rather than mutating that stale reference, is required
+    # for both Eevee thumbnails and glTF image export.
+    for material in bpy.data.materials:
+        if not material.use_nodes or not material.node_tree:
+            continue
+        for node in material.node_tree.nodes:
+            if node.type == "TEX_IMAGE":
+                node.image = image
+
+
+def export_gltf(objects, asset_dir):
+    gltf_path = os.path.join(asset_dir, "model.gltf")
+    select_only(objects)
+    bpy.ops.export_scene.gltf(
+        filepath=gltf_path,
+        export_format="GLTF_SEPARATE",
+        use_selection=True,
+        export_keep_originals=True,
+        export_image_format="AUTO",
+    )
+    with open(gltf_path, "r", encoding="utf-8") as handle:
+        gltf = json.load(handle)
+    for image in gltf.get("images", []):
+        uri = image.get("uri")
+        if not uri:
+            continue
+        # Do not delete the exporter URI. Blender can write it as an absolute
+        # path or a relative traversal back to the user's downloaded source.
+        # The final manifest owns one copied texture under textures/ instead.
+        image["uri"] = "../textures/" + TEXTURE_NAME
+    with open(gltf_path, "w", encoding="utf-8") as handle:
+        json.dump(gltf, handle, indent=2)
+        handle.write("\n")
+
+
+def render_preview(objects, path):
+    scene = bpy.context.scene
+    lower, upper = bounds(objects)
+    span = upper - lower
+    target = (lower + upper) / 2.0
+    target.z = lower.z + span.z * 0.42
+    camera_data = bpy.data.cameras.new("AssetPreviewCamera")
+    camera = bpy.data.objects.new("AssetPreviewCamera", camera_data)
+    scene.collection.objects.link(camera)
+    camera.location = Vector((span.x * 1.18, -max(span.x, span.y) * 1.42, span.z * 0.92))
+    direction = target - camera.location
+    camera.rotation_euler = direction.to_track_quat("-Z", "Y").to_euler()
+    camera.data.lens = 52
+    scene.camera = camera
+    floor_mesh = bpy.data.meshes.new("AssetPreviewFloor")
+    floor_mesh.from_pydata([(-20, -20, 0), (20, -20, 0), (20, 20, 0), (-20, 20, 0)], [], [(0, 1, 2, 3)])
+    floor = bpy.data.objects.new("AssetPreviewFloor", floor_mesh)
+    scene.collection.objects.link(floor)
+    floor_material = bpy.data.materials.new("AssetPreviewFloor")
+    floor_material.diffuse_color = (0.13, 0.16, 0.18, 1.0)
+    floor.data.materials.append(floor_material)
+    for name, location, energy, size in (
+        ("AssetPreviewKey", (span.x, -span.y, span.z * 2.2), 1100, 5.0),
+        ("AssetPreviewFill", (-span.x, -span.y * 0.5, span.z * 1.2), 650, 4.0),
+        ("AssetPreviewRim", (0, span.y, span.z * 2.4), 900, 3.0),
+    ):
+        data = bpy.data.lights.new(name, "AREA")
+        data.energy = energy
+        data.shape = "DISK"
+        data.size = size
+        light = bpy.data.objects.new(name, data)
+        scene.collection.objects.link(light)
+        light.location = location
+        light.rotation_euler = (0, 0, 0)
+        light.rotation_euler = (target - light.location).to_track_quat("-Z", "Y").to_euler()
+    scene.render.engine = "BLENDER_EEVEE_NEXT"
+    scene.render.resolution_x = PREVIEW_SIZE
+    scene.render.resolution_y = PREVIEW_SIZE
+    scene.render.resolution_percentage = 100
+    scene.render.image_settings.file_format = "PNG"
+    scene.render.filepath = path
+    scene.world.color = (0.035, 0.045, 0.055)
+    bpy.ops.render.render(write_still=True)
+    for obj in [camera, floor] + [obj for obj in scene.objects if obj.name.startswith("AssetPreview") and obj not in {camera, floor}]:
+        if obj.name in bpy.data.objects:
+            bpy.data.objects.remove(obj, do_unlink=True)
+
+
+def metrics(objects):
+    lower, upper = bounds(objects)
+    return {
+        "vertices": sum(len(obj.data.vertices) for obj in objects),
+        "triangles": sum(len(loop.vertices) - 2 for obj in objects for loop in obj.data.polygons),
+        "dimensions": [round(value, 4) for value in upper - lower],
+        "materials": sorted({material.name for obj in objects for material in obj.data.materials if material}),
+    }
+
+
+def gallery_html(assets):
+    cards = "\n".join(
+        "<article><img src=\"{preview}\" alt=\"{name}\"><h2>{name}</h2>"
+        "<p>{category} · {triangles:,} tris</p><p>{dims} m</p><p>{materials}</p></article>".format(
+            preview=asset["preview"], name=asset["name"], category=asset["category"],
+            triangles=asset["metrics"]["triangles"],
+            dims=" x ".join(str(value) for value in asset["metrics"]["dimensions"]),
+            materials=", ".join(asset["metrics"]["materials"]),
+        ) for asset in assets
+    )
+    return """<!doctype html><meta charset=\"utf-8\"><title>LowPoly Cars</title>
+<style>body{margin:24px;font:14px system-ui,sans-serif;background:#edf1f3;color:#16212a}main{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}article{background:#fff;border:1px solid #cbd5db;border-radius:6px;padding:10px}img{width:100%;aspect-ratio:1;object-fit:contain;background:#20282e}h2{font-size:15px;margin:8px 0 4px}p{margin:3px 0;color:#4a5862}</style><main>""" + cards + "</main>\n"
+
+
+def verify(output):
+    manifest_path = os.path.join(output, "manifest.json")
+    require_file(manifest_path, "manifest")
+    with open(manifest_path, "r", encoding="utf-8") as handle:
+        manifest = json.load(handle)
+    if not manifest.get("license"):
+        raise RuntimeError("Manifest must state the source license status")
+    ids = [asset["id"] for asset in manifest.get("assets", [])]
+    if len(ids) != len(set(ids)) or not ids:
+        raise RuntimeError("Manifest has missing or duplicate asset IDs")
+    for asset in manifest["assets"]:
+        for field in ("model", "bin", "preview"):
+            require_file(os.path.join(output, asset[field]), asset["id"] + " " + field)
+        if asset["metrics"]["vertices"] <= 0 or asset["metrics"]["triangles"] <= 0:
+            raise RuntimeError(asset["id"] + " has empty geometry")
+        with open(os.path.join(output, asset["model"]), "r", encoding="utf-8") as handle:
+            gltf = json.load(handle)
+        uris = [image.get("uri") for image in gltf.get("images", [])]
+        if uris != ["../textures/" + TEXTURE_NAME]:
+            raise RuntimeError(asset["id"] + " does not reference the shared texture")
+    require_file(os.path.join(output, "textures", TEXTURE_NAME), "shared texture")
+    print("LOWPOLY_CARS_VERIFY", json.dumps({"assets": len(ids), "ids": ids}))
+
+
+def main():
+    args = cli_args()
+    if "verify" in args:
+        verify(os.path.abspath(args["verify"]))
+        return
+    source = os.path.abspath(args.get("source", ""))
+    texture_dir = os.path.abspath(args.get("textures", ""))
+    output = os.path.abspath(args.get("output", ""))
+    require_file(source, "source Blend")
+    texture_path = os.path.join(texture_dir, TEXTURE_NAME)
+    require_file(texture_path, "required shared texture")
+    if os.path.exists(output):
+        raise RuntimeError("Output already exists; remove it only after reviewing its contents: " + output)
+    bpy.ops.wm.open_mainfile(filepath=source)
+    # The source Blend is a display lineup. Hide it before thumbnail rendering;
+    # the normalized temporary mesh objects remain renderable.
+    for obj in bpy.context.scene.objects:
+        obj.hide_render = True
+    os.makedirs(output)
+    shared_textures = os.path.join(output, "textures")
+    os.makedirs(shared_textures)
+    # Match the Cesium tree profile by baking the gain into the output pixels.
+    setup_material_texture(bake_cesium_texture(texture_path, os.path.join(shared_textures, TEXTURE_NAME)))
+    temp = bpy.data.collections.new("LowPolyCarsExport")
+    bpy.context.scene.collection.children.link(temp)
+    assets = []
+    for root in roots():
+        asset_dir = os.path.join(output, root.name)
+        os.makedirs(asset_dir)
+        objects = make_normalized_objects(root, temp)
+        export_gltf(objects, asset_dir)
+        render_preview(objects, os.path.join(asset_dir, "preview.png"))
+        assets.append({
+            "id": root.name,
+            "name": root.name.replace("_", " ").title(),
+            "category": category_for(root.name),
+            "sourceRoot": root.name,
+            "model": root.name + "/model.gltf",
+            "bin": root.name + "/model.bin",
+            "preview": root.name + "/preview.png",
+            "metrics": metrics(objects),
+        })
+        reset_temp_collection(temp)
+    manifest = {
+        "source": os.path.basename(source),
+        "license": "Unknown; verify the original download license before redistribution.",
+        "texture": "textures/" + TEXTURE_NAME,
+        "layout": "Each asset has model.gltf/model.bin/preview.png; the 512px color texture is shared in textures/.",
+        "assets": assets,
+    }
+    with open(os.path.join(output, "manifest.json"), "w", encoding="utf-8") as handle:
+        json.dump(manifest, handle, indent=2)
+        handle.write("\n")
+    with open(os.path.join(output, "index.html"), "w", encoding="utf-8") as handle:
+        handle.write(gallery_html(assets))
+    verify(output)
+    print("LOWPOLY_CARS_DONE", json.dumps({"assets": len(assets), "output": output}))
+
+
+if __name__ == "__main__":
+    main()

scripts/build-area.js

@@ -12,7 +12,7 @@ const {
 } = require("./lib/scene-layers");
 const { digest: glbDigest } = require("./glb-digest");
 const { buildVehicleRoute: buildPreviewVehicleRoute } = require("./lib/vehicle-route");
-const { makeVehicleGltf: makePreviewVehicleGltf } = require("./lib/vehicle-model");
+const { writePreviewVehicleLibrary } = require("./lib/vehicle-library");
 const {
   cesiumPreviewHtml,
   previewSummary,
@@ -468,13 +468,13 @@ function writeCesiumPreview(area) {
   const startedAt = new Date(started).toISOString();
   fs.mkdirSync(path.dirname(htmlPath), { recursive: true });
   writeVehicleRoute(area);
-  writeVehicleModel(area);
+  const vehicleModelNames = writeVehicleModel(area);
   writeCesiumPreviewSupportFiles(path.dirname(htmlPath));
   const glbName = path.basename(area.outputs.glb);
   const metadataName = path.basename(area.outputs.metadata);
   const routeName = path.basename(area.outputs.vehicleRoute);
   const vehicleModelName = path.basename(area.outputs.vehicleModel);
-  fs.writeFileSync(htmlPath, cesiumPreviewHtml(glbName, metadataName, routeName, vehicleModelName, area.id));
+  fs.writeFileSync(htmlPath, cesiumPreviewHtml(glbName, metadataName, routeName, vehicleModelName, area.id, vehicleModelNames));
   console.log(`Cesium preview: ${htmlPath}`);
   const finished = Date.now();
   writeStageManifest(area, {
@@ -510,10 +510,14 @@ function writeVehicleRoute(area) {
 }
 
 function writeVehicleModel(area) {
-  const gltf = makePreviewVehicleGltf();
   fs.mkdirSync(path.dirname(area.outputs.vehicleModel), { recursive: true });
-  fs.writeFileSync(area.outputs.vehicleModel, `${JSON.stringify(gltf, null, 2)}\n`);
+  const outDir = path.dirname(area.outputs.vehicleModel);
-  console.log(`Vehicle model: ${area.outputs.vehicleModel}`);
+  const fileStem = path.basename(area.outputs.vehicleModel, ".gltf").replace(/-vehicle-car$/, "");
+  const models = writePreviewVehicleLibrary(outDir, fileStem);
+  // Preserve the existing output/manifest contract for old preview HTML.
+  fs.copyFileSync(path.join(outDir, models[0]), area.outputs.vehicleModel);
+  console.log(`Vehicle models: ${models.length} candidates in ${path.dirname(area.outputs.vehicleModel)}`);
+  return models;
 }
 
 function sceneGeojsonRecords(area) {

scripts/lib/area-preview.js

@@ -13,13 +13,14 @@ function writeCesiumPreviewSupportFiles(outDir) {
   }
 }
 
-function cesiumPreviewHtml(glbName, metadataName, routeName, vehicleModelName, areaId) {
+function cesiumPreviewHtml(glbName, metadataName, routeName, vehicleModelName, areaId, vehicleModelNames = []) {
   const previewConfig = {
     areaId,
     glbName,
     metadataName,
     routeName,
     vehicleModelName,
+    vehicleModelNames,
   };
   return `<!doctype html>
 <html lang="zh-CN">

scripts/lib/cesium-preview.js

@@ -37,7 +37,7 @@
     const viewer = createViewer();
     setLoadingMessage("Loading model", config.glbName || "");
     const assets = await loadSceneAssets(viewer, metadata, placement);
-    const cruise = addVehicleCruises(viewer, routeData, config.vehicleModelName);
+    const cruise = addVehicleCruises(viewer, routeData, config.vehicleModelNames, config.vehicleModelName);
     const cameras = createCameraPresets(viewer, metadata, placement, cruise);
 
     buildAssetToggles(assets);
@@ -422,7 +422,7 @@
     return stopFollow;
   }
 
-  function addVehicleCruises(viewer, routeData, vehicleModelName) {
+  function addVehicleCruises(viewer, routeData, vehicleModelNames, fallbackVehicleModelName) {
     const segments = ((routeData && (routeData.routes || routeData.segments)) || [])
       .filter((segment) => segment.coordinates && segment.coordinates.length >= 2)
       .slice(0, 5);
@@ -436,7 +436,8 @@
     viewer.clock.shouldAnimate = segments.length > 0;
 
     const vehicles = segments.map((segment, index) => {
-      const vehicle = addCruiseVehicle(viewer, segment, index, start, speed, vehicleModelName);
+      const vehicle = addCruiseVehicle(viewer, segment, index, start, speed,
+        selectedVehicleModelName(vehicleModelNames, fallbackVehicleModelName));
       const option = document.createElement("option");
       option.value = String(index);
       option.textContent = routeLabel(segment, index);
@@ -450,6 +451,14 @@
     };
   }
 
+  function selectedVehicleModelName(modelNames, fallbackModelName) {
+    const choices = Array.isArray(modelNames) && modelNames.length
+      ? modelNames
+      : [fallbackModelName];
+    const usable = choices.filter(Boolean);
+    return usable[Math.floor(Math.random() * usable.length)] || "";
+  }
+
   function addCruiseVehicle(viewer, segment, index, start, speed, vehicleModelName) {
     const route = prepareRoute(segment);
     const positions = new Cesium.CallbackProperty((time, result) => {
@@ -482,9 +491,10 @@
       orientation: routeOrientation(route, start, speed, 0.0),
       model: {
         uri: vehicleModelName,
-        scale: 1.0,
+        // Keep the library's world scale visible. A minimum screen size made
-        minimumPixelSize: 24,
+        // long trucks balloon in overview and at intersections.
-        maximumScale: 80
+        scale: 0.72,
+        minimumPixelSize: 0
       }
     });
     return {

scripts/lib/vehicle-library.js

@@ -0,0 +1,49 @@
+"use strict";
+
+const fs = require("fs");
+const path = require("path");
+
+const VEHICLE_IDS = [
+  "car_a01_002",
+  "car_a02_002",
+  "car_a03_001",
+  "truck_a01_001",
+  "truck_a02_001",
+  "truck_a03_001",
+];
+const LIBRARY_ROOT = path.resolve(__dirname, "..", "..", "assets", "models", "custom", "lowpoly_cars");
+const TEXTURE_NAME = "color_512x512.jpg";
+const REVERSED_MODEL_IDS = new Set(["truck_a03_001"]);
+
+function writePreviewVehicleLibrary(outDir, fileStem) {
+  const textureOutput = `${fileStem}-vehicle-texture.jpg`;
+  fs.mkdirSync(outDir, { recursive: true });
+  fs.copyFileSync(path.join(LIBRARY_ROOT, "textures", TEXTURE_NAME), path.join(outDir, textureOutput));
+  return VEHICLE_IDS.map((id) => {
+    const modelName = `${fileStem}-vehicle-${id}.gltf`;
+    const binName = `${fileStem}-vehicle-${id}.bin`;
+    const sourceDir = path.join(LIBRARY_ROOT, id);
+    const gltf = JSON.parse(fs.readFileSync(path.join(sourceDir, "model.gltf"), "utf8"));
+    for (const image of gltf.images || []) image.uri = textureOutput;
+    for (const buffer of gltf.buffers || []) buffer.uri = binName;
+    if (REVERSED_MODEL_IDS.has(id)) {
+      // The source's longitudinal PCA axis points rearward for this truck.
+      for (const node of gltf.nodes || []) node.rotation = [0, 1, 0, 0];
+    }
+    for (const material of gltf.materials || []) {
+      const pbr = material.pbrMetallicRoughness || (material.pbrMetallicRoughness = {});
+      // Match the Cesium foliage profile: lift albedo first, then use the
+      // texture itself as a modest shadow-side floor.
+      pbr.baseColorFactor = [2.1, 2.1, 2.1, 1];
+      if (pbr.baseColorTexture) {
+        material.emissiveTexture = { ...pbr.baseColorTexture };
+        material.emissiveFactor = [0.25, 0.25, 0.25];
+      }
+    }
+    fs.writeFileSync(path.join(outDir, modelName), `${JSON.stringify(gltf, null, 2)}\n`);
+    fs.copyFileSync(path.join(sourceDir, "model.bin"), path.join(outDir, binName));
+    return modelName;
+  });
+}
+
+module.exports = { VEHICLE_IDS, REVERSED_MODEL_IDS, writePreviewVehicleLibrary };

scripts/test-preview-assets.js

@@ -7,6 +7,7 @@ const os = require("os");
 const path = require("path");
 const { cesiumPreviewHtml } = require("./lib/area-preview");
 const { makeVehicleGltf } = require("./lib/vehicle-model");
+const { VEHICLE_IDS, REVERSED_MODEL_IDS, writePreviewVehicleLibrary } = require("./lib/vehicle-library");
 const { allowedTurns, buildVehicleRoute, classifyConnection } = require("./lib/vehicle-route");
 
 const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "preview-assets-"));
@@ -85,17 +86,39 @@ assert.equal(
   vehicle.buffers[0].byteLength,
 );
 
+const vehicleLibraryRoot = path.join(__dirname, "..", "assets", "models", "custom", "lowpoly_cars");
+if (fs.existsSync(vehicleLibraryRoot)) {
+  const libraryDir = path.join(tempDir, "vehicle-library");
+  const models = writePreviewVehicleLibrary(libraryDir, "fixture");
+  assert.deepEqual(models, VEHICLE_IDS.map((id) => `fixture-vehicle-${id}.gltf`));
+  assert.equal(models.length, 6);
+  assert.ok(fs.existsSync(path.join(libraryDir, "fixture-vehicle-texture.jpg")));
+  for (const model of models) {
+    const gltf = JSON.parse(fs.readFileSync(path.join(libraryDir, model), "utf8"));
+    assert.deepEqual(gltf.images.map((image) => image.uri), ["fixture-vehicle-texture.jpg"]);
+    assert.equal(gltf.buffers[0].uri, model.replace(/\.gltf$/, ".bin"));
+    assert.deepEqual(gltf.materials[0].pbrMetallicRoughness.baseColorFactor, [2.1, 2.1, 2.1, 1]);
+    assert.deepEqual(gltf.materials[0].emissiveFactor, [0.25, 0.25, 0.25]);
+    assert.equal(gltf.materials[0].emissiveTexture.index, gltf.materials[0].pbrMetallicRoughness.baseColorTexture.index);
+    const reversed = model.includes("truck_a03_001");
+    assert.equal(reversed, REVERSED_MODEL_IDS.has(model.match(/vehicle-(.+)\.gltf$/)[1]));
+    assert.equal(gltf.nodes.every((node) => JSON.stringify(node.rotation || []) === JSON.stringify([0, 1, 0, 0])), reversed);
+  }
+}
+
 const html = cesiumPreviewHtml(
   "scene<&>.glb",
   "scene.json",
   "route.json",
   "vehicle.gltf",
   "north<&>\u2028valley",
+  ["car-a.gltf", "truck-a.gltf"],
 );
 assert.match(html, /<title>north&lt;&amp;&gt;\u2028valley Cesium Preview<\/title>/);
 assert.match(html, /Loading scene&lt;&amp;&gt;\.glb/);
 assert.match(html, /"areaId":"north\\u003c\\u0026\\u003e\\u2028valley"/);
 assert.match(html, /"glbName":"scene\\u003c\\u0026\\u003e\.glb"/);
+assert.match(html, /"vehicleModelNames":\["car-a\.gltf","truck-a\.gltf"\]/);
 assert.match(html, /id="viewMode"/);
 assert.match(html, /data-view-mode="inspect"/);
 assert.match(html, /id="semanticToggles" class="control-subgroup hidden"/);