# How to Adopt BIM in the Building Construction Sector across Greece?
## 1 Introduction
Its complete application includes information and data for the whole building from masonry to structural elements to engineering systems, material measurements and suppliers data, for each specific project. The methodology could be applied not only in design but also during the study phase [18; 19]. Its use and advantages extend to all the phases of the project life circle [20] (Figure 1), supporting services such as cost management, project management, constructability and operations management. The final product of such holistic procedure is not simply a better building or a 3D model on the computer [21]. The basic idea of the methodology is the exact, complete planning, study and depicting construction of the building such as it will be built, before it is build, aiming to solve the problems that may arise along the way. Through the production of a model, all the information relating to it can be connected to the depiction of the building, namely, all its structural elements, the construction materials, the stationary equipment, the special constructions, the mobile equipment, etc., along with the respective crews, and companies connected to them [22]. BIM presents each detail and constitutes an open digital archive for the \"reading\" of the building, which can be informed and updated. For this reason, in some countries, the same holistic study and construction methodology is called virtual design and construction (VDC). Regarding BIM's benefits, these mainly refer to the following points [23]:  
* Improved efficiency in the study and construction because of the easy availability of information. * Immediate renewal and greater accuracy of plans. * Greater measurement, cost accuracy and better study quality. * Energy efficiency study very quickly and in an early stage of the study procedure. * Faster project delivery. * Constructability control leading to risk and cost decrease. Despite the advantages presented above, BIM's real value is related to the potential capacities among all the implicated professionals as well as between professionals and clients. With the application of BIM in practice, procedures and analyses are generally facilitated, which up until now were complicated, time consuming and expensive during their effectuation. Finally, the importance of the use of BIM in the attainment of sustainable development on two scales must be underlined: The microscale and the macroscale. In particular:  
* In the microscale, namely on building level, the use of BIM permits the quick and easy extraction of results (integrated outputs) referring to the energy behaviour of each building. At the same time, there is the possibility of strategy selection for resource saving (integrated design and design optimization), resulting in the optimization of planning in order to achieve the \"green goals\" of each project. Actually, through BIM it is possible to draw measurements of energy output in real time (performance monitoring), thus having the possibility to compare between evaluations during the study procedure and the operation phase, in order to promote the optimization of the tools. So it is ascertained that even if the possibilities and applications of BIM on \"green planning\" have not reached their optimal level yet, a wide range of building industry professionals use BIM for delivering green projects [15, 24, 25]. * In macroscale, namely, the level of neighborhood or town, the use of BIM permits the optimization of the planning and management of urban areas, in the following ways: (b1) Easy and quick evaluation of the characteristics of all the buildings regarding a series of structural and town  
Figure 1: The use of BIM during the whole life cycle of a building. Source: [17]. planning characteristics (land use, building height, construction period, architectural morphology, construction and housing material, existence of a yard, etc.). In this way, it is possible to immediately extract results regarding the character of each area and evaluate the value of each unit of real estate.