Embodiments are directed to fuel injectors for internal combustion engines (e.g. engines with reciprocating pistons and with compression-ignition or spark-ignition, Wankel engines, turbines, jets, rockets, and the like) and more particularly to improved nozzle configurations for use as part of such fuel injectors. Other embodiments are directed to enabling fabrication technology that can provide for formation of nozzles with complex configurations and particularly for technologies that form structures via multiple layers of selectively deposited material or in combination with fabrication from a plurality of layers where critical layers are planarized before attaching additional layers thereto or forming additional layers thereon. Other embodiments are directed to methods and apparatus for integrating such nozzles with injector bodies.