Techniques herein provide precise cuts for fins and nanowires without needing dummy gate pairs to compensate for overlay misalignment. Techniques herein include using an etch mask to remove designated portions of gate structures to define a trench or open space having fin structures, nanowires, etc. The uncovered fin structures are etched away or otherwise removed from the trench segments. The etch mask and material defining the trench provide a combined etch mask for removing uncovered fin portions. Subsequently the trench segments are filled with dielectric material. Without needed dummy gate pairs a given substrate can fit significantly more electrical devices per unit area.