Addressing the challenges of surging complexity, cross-disciplinary collaboration barriers, and fragmented models and data in complex system development,
this paper presents the transformation path from "engineering object modeling" to "engineering relationship digitalization." Leveraging requirements traction,
system architecture-driven design, agile iteration, and multi-alternative trade-off as core capabilities, it integrates the full-lifecycle closed loop spanning requirements, design,
virtual verification, and manufacturing through a unified digital thread and authoritative model source. This enables traceable changes, decision-ready alternatives,
and higher R&D efficiency, offering a systematic construction roadmap and practical reference for the digital design of complex systems.