diff --git a/viewer.html b/viewer.html
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+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8" />
+  <title>OBJ Viewer (three.js modules)</title>
+  <meta name="viewport" content="width=device-width, initial-scale=1" />
+  <style>
+    html, body { margin: 0; height: 100%; overflow: hidden; background: #111; }
+    #hud {
+      position: fixed; left: 12px; top: 12px;
+      padding: 10px 12px; border-radius: 10px;
+      background: rgba(0,0,0,0.75); color: #fff;
+      font: 13px/1.4 system-ui, sans-serif;
+      max-width: 460px;
+      white-space: pre-wrap;
+    }
+    #hud b { display:block; margin-bottom: 6px; }
+    code { background: rgba(255,255,255,0.08); padding: 1px 4px; border-radius: 6px; }
+  </style>
+
+  <!-- Import map: map "three" and "three/addons/" to CDN module files -->
+  <script type="importmap">
+  {
+    "imports": {
+      "three": "https://cdn.jsdelivr.net/npm/three@0.160.0/build/three.module.js",
+      "three/addons/": "https://cdn.jsdelivr.net/npm/three@0.160.0/examples/jsm/"
+    }
+  }
+  </script>
+</head>
+<body>
+  <div id="hud"><b>OBJ Viewer</b>Waiting...</div>
+
+  <script type="module">
+    import * as THREE from "three";
+    import { OrbitControls } from "three/addons/controls/OrbitControls.js";
+    import { OBJLoader } from "three/addons/loaders/OBJLoader.js";
+    import { MTLLoader } from "three/addons/loaders/MTLLoader.js";
+
+    const OBJ_URL = "./output.obj";
+    const MTL_URL = "./output.mtl"; // optional
+    const hud = document.getElementById("hud");
+
+    function hudMsg(lines) { hud.textContent = lines.join("\n"); }
+
+    hudMsg(["OBJ Viewer", "Booting (modules)..."]);
+
+    // Scene
+    const scene = new THREE.Scene();
+    scene.background = new THREE.Color(0x111111);
+
+    const camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.01, 1e7);
+
+    const renderer = new THREE.WebGLRenderer({ antialias: true });
+    renderer.setSize(window.innerWidth, window.innerHeight);
+    renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
+    document.body.appendChild(renderer.domElement);
+
+    const controls = new OrbitControls(camera, renderer.domElement);
+    controls.enableDamping = true;
+
+    // Lights
+    scene.add(new THREE.AmbientLight(0xffffff, 0.6));
+    const dir = new THREE.DirectionalLight(0xffffff, 1.0);
+    dir.position.set(3, 5, 4);
+    scene.add(dir);
+
+    function frameObject(obj) {
+      const box = new THREE.Box3().setFromObject(obj);
+      const size = box.getSize(new THREE.Vector3());
+      const center = box.getCenter(new THREE.Vector3());
+
+      obj.position.sub(center);
+
+      const maxDim = Math.max(size.x, size.y, size.z);
+      const fov = camera.fov * Math.PI / 180;
+      let dist = (maxDim / 2) / Math.tan(fov / 2);
+      dist *= 1.6;
+
+      camera.position.set(dist, dist * 0.6, dist);
+      camera.near = Math.max(maxDim / 1000, 0.01);
+      camera.far = maxDim * 1000;
+      camera.updateProjectionMatrix();
+
+      controls.target.set(0, 0, 0);
+      controls.update();
+    }
+
+    async function urlExists(url) {
+      try {
+        // Some servers block HEAD; fall back to GET if needed.
+        let r = await fetch(url, { method: "HEAD" });
+        if (!r.ok) r = await fetch(url, { method: "GET" });
+        return r.ok;
+      } catch {
+        return false;
+      }
+    }
+
+    async function load() {
+      hudMsg(["OBJ Viewer", `Loading: ${OBJ_URL}`]);
+
+      const objLoader = new OBJLoader();
+
+      // Optional MTL
+      const hasMtl = await urlExists(MTL_URL);
+      if (hasMtl) {
+        hudMsg(["OBJ Viewer", `Loading MTL: ${MTL_URL}`]);
+        const mtlLoader = new MTLLoader();
+        const materials = await new Promise((resolve, reject) => {
+          mtlLoader.load(MTL_URL, resolve, undefined, reject);
+        });
+        materials.preload();
+        objLoader.setMaterials(materials);
+      }
+
+      hudMsg(["OBJ Viewer", `Loading OBJ: ${OBJ_URL}`]);
+
+      const obj = await new Promise((resolve, reject) => {
+        objLoader.load(
+          OBJ_URL,
+          resolve,
+          (xhr) => {
+            const mb = (xhr.loaded / (1024 * 1024)).toFixed(2);
+            hudMsg(["OBJ Viewer", `Loading OBJ: ${OBJ_URL}`, `${mb} MB loaded`]);
+          },
+          reject
+        );
+      });
+
+      // Ensure normals/material
+      obj.traverse((c) => {
+        if (c.isMesh) {
+          c.geometry.computeVertexNormals?.();
+          if (!c.material) c.material = new THREE.MeshStandardMaterial({ color: 0xb0b0b0 });
+        }
+      });
+
+      scene.add(obj);
+      frameObject(obj);
+
+      hudMsg([
+        "OBJ Viewer",
+        "Loaded OK",
+        hasMtl ? "MTL: used" : "MTL: not used",
+        "",
+        "Left drag: rotate",
+        "Wheel: zoom",
+        "Right drag: pan"
+      ]);
+    }
+
+    load().catch((e) => {
+      console.error(e);
+      hudMsg([
+        "OBJ Viewer",
+        "ERROR",
+        String(e),
+        "",
+        "Open DevTools -> Console for details."
+      ]);
+    });
+
+    function animate() {
+      requestAnimationFrame(animate);
+      controls.update();
+      renderer.render(scene, camera);
+    }
+    animate();
+
+    window.addEventListener("resize", () => {
+      camera.aspect = window.innerWidth / window.innerHeight;
+      camera.updateProjectionMatrix();
+      renderer.setSize(window.innerWidth, window.innerHeight);
+    });
+  </script>
+</body>
+</html>
