Briefly, the building information model can be regarded as a digital three-dimensional geometric model of the building. In addition, all the information contained in the building components in this model is not only geometric figures, but also architectural or engineering data. These data provide sufficient calculation basis for the program system, so that these programs can automatically calculate the accurate information needed by the inquirer according to the data of the component. The information referred to here may take many forms, such as building plan, elevation view, section view, detail view, three-dimensional view, bill of materials or calculation of lighting effect of natural lighting in each room, required air conditioning ventilation, required air conditioning power consumption in winter and summer, etc.