In parallel with the development of new technologies, new device configurations, and new applications for microsensors, microactuators, and microsystems, also referred to as microelectromechanical devices and systems (MEMS), there has arisen a growing need for computer-aided engineering and design systems. There is a wide range of design problems: process simulation, solid-body geometric renderings from photomasks and process descriptions, energetically correct simulation of behavior across multiple coupled energy domains, extraction of lumped low-order models of device behavior, optimization of geometry and process sequence, and design of full systems that include MEMS devices. Because of the computational demands of the modeling required to support full computer-aided design (CAD), there is a premium on fast and memory-efficient algorithms that help the designer, both by automating, where possible, complex sets of related tasks and by providing rapid computational prototyping at critical points in the design cycle. This paper presents an overview of the present state of the art in CAD for MEMS, with particular emphasis on the role of macromodels and test structures as part of the design environment.