I had the pleasure of sitting down with Bill Wright of Wrightsoft the other week, and although my focus has been squarely on the creation of architectural BIMs, specifically from an existing conditions / as built perspective I was really impressed with what they are doing. While working in 2D the amount of meta data contained in the lines is amazing, along with the inherent logic of their drafting tools makes it an impressive package. Bill was driving through the software and showed how spaces without an adjoining space was assumed to be an exterior wall, and the levels, which has a very similar hierarchical/navigation structure uses information from the other levels to create its calculations. This is powerful analysis and HVAC design software that can provide what type of plant you might need and if you throw a window it will automatically make the duct wider for increased airflow and then create the build list. With all the talk about BIM, Bill and his crew have been providing its benefits in 2D for years. Meta Data, Analysis, Scheduling, Build Lists, etc.