3D object

Model a 3D object the user can inspect from every angle and download, built with three.js and presented in the three_d_stage starter.

START by calling copy_starter_component with kind: "three_d_stage.js" — it is the whole viewer: studio lighting, ground shadow, orbit controls, an auto-framed camera, and a toolbar that downloads the object as OBJ + MTL or GLB. Read the copied file's usage block and follow its page skeleton exactly. You only write the model-building module script.

Build the page as plain HTML — a .html file with ordinary <script> tags — even when the project's other designs are .dc.html Design Components: DC restricts scripts to <helmet>, which races the stage's mount and can't host this skeleton.

Load three.js ONLY through this exact pinned import map, in <head>, before any module script. Do not change versions, URLs, or hashes, do not add other copies of three.js, and do not import addons beyond the three listed — the map is deliberately a closed set, so anything else fails to resolve rather than loading unverified:

<script type="importmap"> { "imports": { "three": "https://unpkg.com/three@0.184.0/build/three.module.js", "three/addons/controls/OrbitControls.js": "https://unpkg.com/three@0.184.0/examples/jsm/controls/OrbitControls.js", "three/addons/exporters/OBJExporter.js": "https://unpkg.com/three@0.184.0/examples/jsm/exporters/OBJExporter.js", "three/addons/exporters/GLTFExporter.js": "https://unpkg.com/three@0.184.0/examples/jsm/exporters/GLTFExporter.js" }, "integrity": { "https://unpkg.com/three@0.184.0/build/three.module.js": "sha384-8FCZ1eVO6it4+pbec2aDtnTrwjWXZLJRC+MAGCIPDgsYnUrl/E0A2YlF8ioMKI/J", "https://unpkg.com/three@0.184.0/build/three.core.js": "sha384-dw2ooPewaEIrAgl6oFDBmmBWCE9oW9LxRGcfwZ0hLvEprzo202wXl7vCYHRlSnOT", "https://unpkg.com/three@0.184.0/examples/jsm/controls/OrbitControls.js": "sha384-4rziNxOBZKQ69i+w+f89KJ55TCYquwchVbByQwmaOeIOXdOU2PLDn3kOfXHwIJC9", "https://unpkg.com/three@0.184.0/examples/jsm/exporters/OBJExporter.js": "sha384-nbwtoZENJD3Vq+ACK0CuGQdPMuDWHkamC2KJD70EV5nfg6jQjfppKOea07YJN+N3", "https://unpkg.com/three@0.184.0/examples/jsm/exporters/GLTFExporter.js": "sha384-VofkvpG6HERhFCYbsUOHeNXBCqID2nfqkQqnVzE1jc/oPcz+qJ13ADdXH08hE+cQ" } } </script>

Build the model programmatically, as a THREE.Group composed of named parts:

• Compose primitives (BoxGeometry, CylinderGeometry, SphereGeometry, TorusGeometry, LatheGeometry, ExtrudeGeometry with Shape) before reaching for raw BufferGeometry; real objects decompose into far more primitives than you'd guess.
• NAME every mesh and every material ("hull", "walnut", "brass") — the names become the o / usemtl entries in the exported OBJ and the node names in the GLB, which is what makes the download usable in Blender.
• Use MeshStandardMaterial with a small curated palette (3-5 materials, shared across parts); set roughness/metalness deliberately. Textures don't survive the OBJ export — prefer geometry and material color over texture detail.
• Model in real-world meters, y-up, centered on the origin, base resting at the lowest y. Offset deliberately coplanar faces by ~0.001 so nothing z-fights.
• Curved surfaces need enough segments to read as smooth at full screen (32+ radial segments on feature surfaces), but don't tessellate what no one will see.

The stage's toolbar gives the user OBJ + MTL (universal, geometry + per-material colors) and GLB (the modern interchange format — keeps the part hierarchy and PBR materials; imports cleanly into Blender, Maya, Cinema 4D, Unity, Unreal). Those two are the export formats on offer — when the user asks for something else (FBX, USDZ, STEP), say plainly that the stage exports OBJ + MTL and GLB.

Iterate with screenshots: the stage keeps its last frame readable, so the ordinary screenshot tools capture the live canvas — no extra steps. After editing a module file, reload with show_html before screenshotting (the iframe caches already-loaded modules). Look at the object from the default framing and refine silhouette, proportion, and material separation — the silhouette carries the object.