## 3 BIM and DTs--Latest Development Trends and Challenges
### Important Challenges and Research Directions  
The challenges and development trends of BIM and DT methods and tools were discussed in Section 3. However, considering the conclusions of the discussion in Section 4, the authors identify the most significant challenges and trends in the development of BIM and DTs. These are of particular importance in the context of supporting the implementation of BACS function design mechanisms and the technical organization of distributed networks with the IoT as well as their primary and functional verification at the stages of construction and operation in buildings. As previously stated, the paramount concern in facilitating comprehensive and multifaceted integration of BIM and DT software ([[https://www.dt-software.co.uk/](https://www.dt-software.co.uk/)]([https://www.dt-software.co.uk/](https://www.dt-software.co.uk/))) platforms with physical objects of distributed BACS networks with IoT guarantee the integrity and dependability of their data, as well as the reliability of their communication and processing. The availability of real data is the most significant factor in determining the efficacy of the utilization of BIM and DT tools in combination with BACS and BMS technologies, during both the design and operational phases. The EN ISO 52120 standard and the SRI methodology provide guidelines for the selection of functions, control services, and monitoring of buildings but do not contain any indications regarding preferred technologies. Therefore, an open environment is created for the implementation of various technical solutions in the field of distributed automation networks and the IoT. Nevertheless, as evidenced by the experience of numerous years of implementing BACS and BMS systems shows, the optimal outcomes are achieved by implementing installations based on open, nonproprietary standards [116; 117; 118]. The authors point out the necessity to develop novel mechanisms for the interoperability of communication protocols and communication media for object-level networks, with the objective of enabling data communication with higher-level networks (the Internet) while ensuring a high level of communication security, data coding, and the maintenance of the requirements for the operation of automation modules in the real-time regime. Systematized guidelines for the selection and organization of BACS control functions and services specified in the EN ISO 52120 standard and for SRI represent an optimal set of parameters for implementation in BIM and DT tools. As previously stated, the implementation of these guidelines will not only facilitate the design and operation procedures of buildings but also allow for the benchmarking and performance tracking of such buildings. In particular, the SRI provides a standardized framework for the benchmarking and tracking of the building sustainability index over time. This enables building owners and operators to evaluate the efficacy of BACS and IoT-based initiatives and identify areas for further enhancement. Further support in this area will be provided by the integration of real system installations with DT models, which also enable the prediction of potential control scenarios and the analysis of dynamic changes in building utility parameters. These include variable energy tariffs, changes in load levels of household appliances, and the infrastructure of local microgrid networks. Finally, it is crucial to emphasize the importance of proactive promotion of sustainable practices. This is particularly pertinent in the context of the implementation of effective energy management mechanisms at various levels, including the production and distribution of energy, as well as servicing of prosumers at the level of building complexes or individual facilities. Both EN ISO 52120 and SRI promote the implementation of sustainable building management practices by encouraging the integration of IoT technologies and cloud services to optimize energy efficiency, reduce environmental impact, and improve user comfort.