Divide and Conquer

The ‘when to divide’ and ‘how to divide’ topic has a million shades of gray.  The process does have some overhead time required to setup.  When needed though, there seems to be three schools of thought on how to divide a project. The first is across the match lines. The second is by floor. Then the third is by discipline.

Well, for Architecture it makes sense to be able to divide by the match lines, but not for MEP. As of Revit MEP 2015, system information cannot be passed through a linked file.  Yes, you can tag through a linked file, but that is not the same as passing system information along.  If the electrical panel that serves an outlet is in a different file, then it can’t be added as a load to the panel.  Air Handling Units in one file, can’t add CFM’s from terminal units in linked files.  Largely, this approach just does not work for MEP.

The second approach of by floor has the same limitations. If the systems need to be able to connect vertically though the building, they won’t be able to. This leaves only one viable option left, dividing the model by discipline.

On large projects dividing the models is a must to gain efficiency, but on smaller projects, where is the cut-off for a return on the time investment?  Buildings 30,000-50,000 Sqft and smaller are generally manageable as single project files.  For larger projects, it makes since to create separate Revit MEP models. I prefer to divide them per trade (Electrical, Plumbing, & HVAC), then interlink each into the others by placing them on separate worksets unique to each linked file.  Finally setup the central file to inquire as to which worksets to load upon opening. If the workset for electrical is not selected upon opening the HVAC model, then none of the electrical objects will be loaded into active memory.  This can free up huge chunks of memory.  Dividing worksets into logical chunks helps with linked files even more.  Let’s say the electrical model is linked into the HVAC model.  To coordinate the ceilings, the workset for lights can be the only workset loaded into the HVAC model.  To manage the worksets within linked files use the Manage Links tool as shown below.