ergonomic office chair 3d model

Create a complete, watertight, production-ready 3D model of a modern ergonomic office chair. Requirements: - Include the seat, backrest, armrests, five-star base, caster wheels, support column, and adjustment levers. - Generate the entire object from all angles, including the underside. - Use black breathable mesh for the backrest, dark gray fabric for the seat cushion, and matte aluminum for the frame and base. - Ensure realistic proportions and accurate geometry. - Apply physically based rendering (PBR) materials with 4K textures. - Create clean topology suitable for editing and real-time rendering. - Center the model at the world origin (0,0,0). - Maintain a real-world height of approximately 120 cm. - Avoid holes, floating components, overlapping geometry, or non-manifold edges. - Optimize for game-engine use. - Export as a single GLB file with embedded textures.