||In earlier times in which computers have not yet been developed well, there has been some researches regarding representation using conventional media (Gombrich, 1960; Arnheim, 1970). For ancient architects, the design process was described abstractly by text (Hewitt, 1985; Cable, 1983); the process evolved from unselfconscious to conscious ways (Alexander, 1964). Till the appearance of 2D drawings, these drawings could only express abstract visual thinking and visually conceptualized vocabulary (Goldschmidt, 1999). Then with the massive use of physical models in the Renaissance, the form and space of architecture was given better precision (Millon, 1994). Researches continued their attempts to identify the nature of different design tools (Eastman and Fereshe, 1994). Simon (1981) figured out that human increasingly relies on other specialists, computational agents, and materials referred to augment their cognitive abilities. This discourse was verified by recent research on conception of design and the expression using digital technologies (McCullough, 1996; Perez-Gomez and Pelletier, 1997). While other design tools did not change as much as representation (Panofsky, 1991; Koch, 1997), the involvement of computers in conventional architecture design arouses a new design thinking of digital architecture (Liu, 1996; Krawczyk, 1997; Murray, 1997; Wertheim, 1999). The notion of the link between ideas and media is emphasized throughout various fields, such as architectural education (Radford, 2000), Internet, and restoration of historical architecture (Potier et al., 2000). Information technology is also an important tool for civil engineering projects (Choi and Ibbs, 1989). Compared with conventional design media, computers avoid some errors in the process (Zaera, 1997). However, most of the application of computers to construction is restricted to simulations in building process (Halpin, 1990). It is worth studying how to employ computer technology meaningfully to bring significant changes to concept stage during the process of building construction (Madazo, 2000; Dave, 2000) and communication (Haymaker, 2000).In architectural design, concept design was achieved through drawings and models (Mitchell, 1997), while the working drawings and even shop drawings were brewed and communicated through drawings only. However, the most effective method of shaping building elements is to build models by computer (Madrazo, 1999). With the trend of 3D visualization (Johnson and Clayton, 1998) and the difference of designing between the physical environment and virtual environment (Maher et al. 2000), we intend to study the possibilities of using digital models, in addition to drawings, as a critical media in the conceptual stage of building construction process in the near future (just as the critical role that physical models played in early design process in the Renaissance). This research is combined with two practical building projects, following the progress of construction by using digital models and animations to simulate the structural layouts of the projects. We also tried to solve the complicated and even conflicting problems in the detail and piping design process through an easily accessible and precise interface. An attempt was made to delineate the hierarchy of the elements in a single structural and constructional system, and the corresponding relations among the systems. Since building construction is often complicated and even conflicting, precision needed to complete the projects can not be based merely on 2D drawings with some imagination. The purpose of this paper is to describe all the related elements according to precision and correctness, to discuss every possibility of different thinking in design of electric-mechanical engineering, to receive feedback from the construction projects in the real world, and to compare the digital models with conventional drawings.Through the application of this research, the subtle relations between the conventional drawings and digital models can be used in the area of building construction. Moreover, a theoretical model and standard process is proposed by using conventional drawings, digital models and physical buildings. By introducing the intervention of digital media in design process of working drawings and shop drawings, there is an opportune chance to use the digital media as a prominent design tool. This study extends the use of digital model and animation from design process to construction process. However, the entire construction process involves various details and exceptions, which are not discussed in this paper. These limitations should be explored in future studies.