## 2 BIM and DT Idea and Applications
BIM is also used to assess the performance of buildings after construction, encompassing actual energy consumption as well as flexibility to dynamic changes [34]. 5. Modernization and demolition: Over time, the building may require upgrading or incorporation of intelligent systems. Users and facility managers need to introduce  
Figure 1: Contemporary, innovative areas of BIM applications. new technologies, and adapting to changing conditions, regulations, and technical and safety requirements is important [35]. Following a lengthy service life, demolition may be required considering the principles of disposal of building and construction materials and their potential for recycling [36]. This brief overview shows that multithreaded support for BIM tools is still developing. A particularly important aspect is the possibility of an integrated approach in the design and management of building infrastructure, which has been raised for many years by engineers and experts in the BACS building automation industry [6; 37; 38; 39]. The concept of the universality of proposed functional blocks is not a new idea, but its application in the discussed subject is a challenge that has not yet been solved and is described rather than initiated. The ability to introduce integrity between the various parts of a building system, regardless of the software or device manufacturer, is an attractive vision of the future, discussed in the sources mentioned above. The development of the BIM implementation concept in the BACS organization is also supported by standards defining automation functions and methods for specific building infrastructure subsystems. All this constitutes a new opening of BIM application possibilities in the abovementioned design process but also in the effective and dynamic operation of modern buildings discussed in Section 3. Another approach and technology that supports the monitoring and effective management of modern buildings is the DT. However, it should be noted that this approach is intended to be universal and can be used in many industries and application areas. As indicated in [40; 41; 42], DTs comprise a technology used in various sectors such as industry, engineering, healthcare, and others. Moreover, they are dynamic in nature, depending on the character of the objects for which a digital replica is created. The publication [43] establishes the idea of the DT. This shows how supply and demand not only for products but also for functionality will drive the market and the direction of technology development. Modern DTs can work with various types of data, static and dynamic (real-time), which enables them to perform interactive simulations, predict potential threats, develop used scenarios, and so forth. Consequently, [PERSON] et al. [27] identified three organizational areas of modern DT applications, as illustrated in Figure 2, which support the implementation of BACS systems, enhance the smartness of buildings, and facilitate collaboration between the physical and virtual layers. The typical DT consists of three principal components, which correspond to a distinct stage or function [27; 28]:  
* A physical object is an actual object that is modeled by a DT. It can be any physical object, such as an entire city, in extreme examples. The physical object is equipped with every type of sensor and other devices that measure and record data, which are then transmitted to the digital components of the DT. * A digital model is created using a variety of techniques, including 3D modeling, computer simulations, and ML. The digital model contains detailed information about the physical object, its parameters, current state, mode of operation, and interdependencies with the environment and users. DTs are classified into three categories: machine, product, and process [44]. The first of the digital machine twins are used to model and simulate machine operations, which enables the prediction of failures and the opti  
Figure 2: Digital twin basic composition. mization of maintenance.