## 3 Results and Discussion
For example, we observed incorrect definitions of some thermal zones, requiring manual corrections and thus increasing the time required for processing. 2. Mismatch in the Definition of Boundary Conditions: Boundary conditions, such as thermal loads or solar gains, were represented in a simplified manner within the gbXML format. This may affect the accuracy of simulations, particularly for buildings with complex shading elements or unusual structural features. Differences in Supported Standards: Different software platforms implement the gbXML format differently, making smooth data transfer more challenging. This discrepancy was identified when working with exports from ArchiCAD to SW Stabil, where certain parameters had to be manually verified. Interoperability between BIM and BEM platforms is a key factor for efficient data transfer and accurate energy performance simulations of buildings. Although gbXML is a widely accepted standard for integrating these two environments, its practical implementation encounters several challenges, such as inconsistencies in processing geometric data, limited export capabilities for complex material properties, and variability in how different software platforms interpret the data. These challenges can result in additional time and manual effort, impacting the overall quality of the simulation results. To enhance interoperability, both technological and process-oriented improvements are necessary to ensure more efficient and consistent data transfer between BIM and BEM tools. The following recommendations outline the key measures that could help mitigate these limitations and improve the quality of energy simulation outcomes:  
1. Implementation of Data Validation in the BIM-BEM Workflow: A critical step toward improving interoperability is the development of advanced algorithms for data consistency checks during the export and import of gbXML files. These algorithms should automatically verify geometric accuracy, completeness of data attributes, and compatibility with the target BEM platform. This would reduce the risk of manual errors and improve simulation accuracy. 2. Expanding the Functionality of the gbXML Format: Since gbXML is primarily designed for transferring geometric and thermodynamic properties, further expanding its data model could allow for the inclusion of more detailed parameters, such as moisture dynamics, precise specifications of material layers or interactions with ventilation systems. These enhancements could be standardised through broader collaboration between BIM and BEM tool developers. 3. Integration with Advanced Simulation Tools: The introduction of advanced simulation tools capable of working natively with gbXML data while minimising the need for additional manual adjustments could significantly increase the efficiency of the BIM-BEM workflow. For example, integrating gbXML with dynamic simulation tools such as OpenStudio or EnergyPlus could provide more accurate results with less user intervention. 4. Standardisation of Export and Import Processes: Improving standards for data export and import would ensure more consistent data transfer across different software platforms. This could include the introduction of a common framework for interpreting gbXML data across various tools, eliminating the current variability in how the format is implemented by different developers. 5. Collaboration among Software Developers: Achieving seamless interoperability requires closer collaboration between BIM and BEM software developers. This collaboration could involve sharing open data formats, reference projects, and the development of application programming interfaces (APIs) to facilitate integration across different platforms.