As automotive systems become more complex, manufacturers face pressure to reduce costs and improve efficiency for faster architecture design. Traditional document-based design methods are no longer suitable for developing complex systems because of difficulties in sharing data, costly design changes, and limited system-level validation. Digital engineering, enabled by Model-Based Systems Engineering (MBSE), offers a promising paradigm of more efficient system design. However, current MBSE approaches still face challenges in system-level mission-operation analysis and multi-architecture modeling. To address this problem, this paper proposes a Mission-Operation-Function-Logic-Physics (MOFLP) based forward design method that supports full lifecycle and multi-architecture modeling-from mission analysis to physical design. It enables complex modeling at system, subsystem, and integration levels, and it allows early design validation to reduce R&D costs of forward design. A case study on an automotive window control system is implemented to verify the proposed method. Its effectiveness is verified through functional modeling, hierarchical representation, and parameter validation. This work provides a potential solution for promoting the automotive industry toward the digital engineering paradigm.