If data can’t be freely used, re-used, re-published and redistributed by anyone, then it isn’t open and is therefore considered proprietary. While I am a supporter of open data, I won’t provide an argument on which method is preferable here. For balance, I will acknowledge that interoperability can be achieved using either proprietary or open data. What I intend to focus on is the prevalence of proprietary and open data within construction projects. Figures vary, but a construction project will typically exchange thousands of digital files. What I find astounding is the amount of these files which utilize open data. Almost all of them!
Some quick maths. Following a discussion with several peers, there is a consensus that ~5% of files on a construction project are model files, such as topographical models, or building / infrastructure models. While these files can be exchanged using open data formats, for example using IFC data models defined within ISO 16739-1, they are more often than not exchanged using a proprietary file formats. In contrast, the remaining 95% of files are correspondence, documents, drawings, photographs, minutes, presentations, reports, schedules, specifications, or visualizations. For these files, we default to open data formats: