# Interoperability Analyses of BIM Platforms for Construction Management
## 4 Discussion  
In this study, data exchange between widely used BIM software packages was assessed. The interoperability tests were carried out by simulating the communication between the design team and the project management team by exchanging 4D BIM models and schedule information represented by Gantt charts. The obtained results were assessed according to the capability of transferring the time information, schematic data, and metadata embedded to the elements in the sample model and the related Gantt chart sample. Software packages were categorized depending on their main capabilities and features. In particular, Trimble Tekla Structures was used to produce both the benchmark 4D BIM model and the related Gantt chart. ACCA Edificius, usBIM.viewer+, and Graphisoft Solibri were tested from the point of view of model exchange through the IFC standard, being used mainly for design and check purposes. Microsoft Project (in its versions 2013 and 2016), used especially for project management, was tested for Gantt chart exchange. Autodesk Navisworks and Synchro Pro were tested in both ways since they are capable of managing 4D information embedded in both IFC models and Gantt charts. For Gantt chart exchanges, reverse analyses were also conducted in order to verify possible issues due to the round-trip of data and to confirm the \"direct\" tests. Regarding the assessment of data exchange in terms of 4D BIM models through IFC format, with respect to the benchmark model produced by Tekla Structures, for each element, four different parameters were evaluated after importing the files into different software, namely, the name of the element, its geometry and appearance, and the fields \"Material Type\" and \"Phase Number\" are properly assigned. The results presented in the previous sections are summarized in Table 8. Considering that a perfect replica of the benchmark BIM model produced by Tekla Structures was never obtained after the exchange with a different platform, a qualitative assessment was done. The names of the elements were always correctly transferred, while some mismatches were found in the geometry; these mismatches incurred in the tests. For example, for Element 7, the reinforcements of a column and its stirrups were correctly represented by only one of the tested software packages (Solibri), leading us to think that the issue was not due to the Tekla Structures IFC exporter module but in the IFC importer module of the other software packages. Element 14 referred to a wall whose surface treatment was not well represented in the importing software, but this could be considered as a minor issue. In fact, considering the metadata referring to the material of the elements, in just one case, the field was not correctly transferred but, in some way, translated on a different \"scale\", assigning a different identification to each material. This would not mean \"loss of information\", but in case of multiple exchanges, this could represent a cause for reworks or misunderstandings between stakeholders. Regarding time information, which is crucial for project management, the phases assigned in the benchmark model were only partially exchanged. Excluding the case when this parameter was totally lost, each software lost this information for some of the elements. Since most of the missing information \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Fields** & **Task Name** & **Task Start Date** & **Task Duration** & **Task End Date** \\ \hline MS Project 2013 & \(\surd\) & \(\surd\) & \(\blacksquare\) & \(\surd\) \\ MS Project 2016 & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ Navisworks (with Round-Trip) & \(\surd\) & \(\surd\) & \(\times\) & \(\times\) \\ Navisworks (without Round-Trip) & \(\surd\) & \(\surd\) & \(\times\) & \(\times\) \\ Synchro Pro & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ \hline \hline \end{tabular}
\end{table}