Schematic-based lumped parameterized behavioral modeling and simulation methodologies have become available since the emergence of analog HDLs. They greatly ease iterative hierarchical multi-domain simulation, which is critical to the design of MEMS. NODAS is one of such tools, with models written in VerilogA and simulation performed within the Cadence framework. This paper focuses on several key modeling issues in NODAS, including schematic representation, element communication, linear, nonlinear and multi-domain modeling, and extensibility to new physical effects, processes and physical domains. A nonlinear beam model and an electrostatic gap model are discussed as examples. Simulation comparison to finite element analyses and experimental data verifies the accuracy of the models and validates the simulation methodology.