Issues with Interoperability

The 3^rd Chapter of the BIM Handbook covers the methods and difficulties associated with transferring data from one BIM application to another. The problems occur in different phases of the data transfer process. First it is important to note that many of the issues begin in the conception of the model. Different users will model the same element in different ways with different degrees of complexity. One user, for instance, may model a three-dimensional surface as a shell, as an extrusion, or a wire-frame. When this data is converted to a neutral file format, although all three represent the same real world element, they will be defined differently, and thus the terminal BIM program will import them differently. The challenges of creating a capable neutral file format such as IFC are thus compounded. Good practice measures for modeling would greatly reduce this problem. As was hinted at above, problems also arise in the export of the files by the native program, the capabilities of the neutral file format, and finally the importing of that file into the terminal program. The resolution of these problems will increase the effectiveness and applicability of BIM software. I expect these issues will eventually be resolved, but I anticipate that the improvements in interoperability will always lag greatly behind the improvements of the BIM software itself.

The problems previously discussed were examined in a more illustrative manner in the second article I read entitled “Benchmark tests for BIM data exchanges of precast concrete.” This article detailed the efforts of the authors to test the interoperability of the leading BIM software using IFC and SAT neutral file formats. Specifically, they explored the feasibility of taking an architectural model of precast concrete panels from a common architectural BIM tool and transferring it into a fabrication modeling tool. They used Revit Building, ArchiCAD, Digital Project, and Bentley Architecture for the architectural BIM tools and Tekla Structures and Structureworks Precast for the precast concrete BIM tools. While most of these programs were capable of using IFC for export and import file formats, Structureworks Precast only supported SAT file format. The testing consisted of first creating the sample model in each of the four architectural modeling tools. These models were created by employees of the respective companies who were experts with the program. The model was first exported and then imported back into the original program. Even this resulted in a large amount of data loss and corruption. The exported files were then translated by the precast concrete BIM tools, with similar results. The lack of good practice measures for modeling and the need for improvement of the IFC format were the cause of the majority of problems.

The article clearly illustrates how the inability of BIM programs to effectively transfer data back and forth severely limits the capabilities of BIM. Work must be duplicated several times between the creation of the first building model and the manufacturing models. This not only is a gross inefficiency but also introduces more errors in the model as users besides the original designer have to make decisions on how different elements fit together, their exact shape, even their location.