Building information modeling, Data conversion
In recent ten years, Building Information Modeling (BIM) has been proposed and applied in the industry of architecture. For the high efficiency and visualization, BIM and correlative technologies are welcomed by architects, engineers, builders and owners, thus the technologies on modeling for design has been widely researched. However, little attention is given to simulation while simulation is an important part of design for building, maybe because it is seen as somewhat less related to the technologies on modeling for design. The paper proposed a simulation framework with four stages of design: concept stage, scheme design stage, preliminary design stage and construction drawing design stage. The principles of simulation are different in each stage, and were given in the paper. In concept stage, simulation focuses on the blocks of building, and the unit of simulation grid is comparable with the unit of field. And the objects of simulation in the stage are wind, light and sound. In scheme design stage, the unit of simulation grid is similar to the one in concept stage. The objects of simulation in the stage are heat, wind, light, energy consumption and sound. In preliminary design stage, simulations turn to pay attention to the systems of the building, such as the energy system, power system, transmission and distribution system, air-conditioning system and ventilation system. The unit of simulation grid is comparable with the unit of indoor space of building. In construction drawing design stage, the details of system is the main objects of simulation, the unit of simulation grid is usually 100-500mm. The data conversion is also discussed, because data conversion is important for the simulation in BIM system. Previous simulation paid much more time on modeling because the buildings were often designed with 2D floor plan while simulation models often were 3D model. The simulation in BIM process makes the modeling easier and quicker. However, the data of different formats have difficulties on modeling conversion. Several main formats of 3D-model are discussed in the paper. The models of gbXML, Sketch Up, 3ds, CATIA, Rhino and Revit can be transferred to simulation software and modified to meet the need of simulation. The transfer principles of each format during different stage are discussed in the paper. The gbXML and Revit have advantages as less workload on modification, less information lost in the conversion and quick response to the change of model. An example of whole process of simulation in BIM design is proposed in the paper. The simulations for the BIM process are applied in the design of Zhuhai Grand Theater. The simulation in Zhuhai Grand Theater also can be divided into four stages. The example mainly focused on the indoor and outdoor wind environment and energy consumption, and the data conversion is applied in the simulation. The efficiency of such simulation process was compared with the traditional process and the result showed that new simulation process in BIM has advantages as time saving, simple and easily controllable.