Laser additively manufactured microscale metallic lattices show great potential for high-performance applications, yet trade-offs among geometric precision, structural integrity, and computational efficiency still persist. Here, we introduce a stereolithography file format-free (STL-free) hybrid toolpath generation method for laser-based powder bed fusion (PBF-LB) that synergizes implicit geometric modeling with optimized laser scanning strategy, overcoming these limitations. By circumventing traditional mesh-based workflows, our method directly translates implicit lattice geometries into laser toolpaths while precisely regulating energy deposition trajectories. This mesh-free process enables the fabrication of complex shell lattices with ultra-thin walls and enhanced surface quality. In addition to reducing memory usage and processing time by up to 90%, the method yields a synergistic enhancement in mechanical performance, notably improving both strength and toughness. By bridging computational design and fabrication, this framework enables the scalable production of high-performance microscale lattices and unlocks their potential for industrial applications.