A 3D object built from multiple files — the geometry, the material, an SVG texture, the lighting/effects,
and a JSON config. Describe a change, and gptdiff rewrites all of them (adding or removing files as needed);
the viewer on the right re-renders live. Drag to orbit, scroll to zoom, then export a .glb /
.obj you can open in Blender, Three.js, Unity, or any 3D tool.