Dropped into a dark room — an AI Studio export called "Spatial Understanding for SUV Modifications" — and found something genuinely useful hiding under the scaffold. Upload a photo of your van's empty cargo area, and Gemini 2.5 Flash traces every edge: floor outline, wheel wells, trim contours. It returns measurements in inches and a closed floor_outline path that Three.js extrudes into a 3D preview you can orbit. The system prompt is a full-page fabrication brief — it tells the model to think like a van builder, not a vision demo.
The catch: it's a raw export. @react-three/fiber 8.x ships with React 19, which means --legacy-peer-deps to install. The example van images point to a GCS bucket that returns 404. The src/ directory has diverged copies of atoms.tsx and consts.tsx — the root versions are the live ones, but the originals had different default images (stock objects like pumpkins and clocks instead of van interiors). The JSON parsing is blind JSON.parse() with no fallback — if Gemini returns markdown-wrapped JSON (which it does about 30% of the time), the app crashes. 24 source files, 2,839 lines, zero git history. Status: raw-export, needs the standard cleanup pass before it's gallery-ready.