AutoCAD MEP 2008 Format change

AutoCAD MEP 2008 did indeed introduce a file format change. This was prompted through making significant enhancements to the display of MEP objects, i.e. rise/drop graphics, hidden lines, display component control and the such. The changes made to the objects introduced a new object version which is what brought on the file format change and the backward compatibility limitations. The actual AutoCAD drawing version still remains a 2007 DWG version which is what you will notice when you save a drawing. The file type is AutoCAD 2007 Drawing (*.dwg).

When ever a file format change happens there are always limitations when saving back to previous versions. In the case of AutoCAD MEP 2008 only visual fidelity is maintained when saving back, and no functionality is preserved. Therefore you can not continue to work on a drawing that you started in MEP 2008 in 2007.

Autodesk has minimized the impact of the file format change by maintaining visual fidelity between releases if you save the 2008 drawing with PROXYGRAPHICS set to 1. You won't be able to work on a 2008 drawing in 2007, and you will have to deal with proxy graphics, but the drawing will look exactly the same to help with sharing of drawings.

So what does this mean to you?

It depends on your environment and how you share drawings. If everybody in your company is on the latest version, and you need to send your 2008 MEP drawings to a client or a contractor or an owner who has 2007 version of MEP, you can use the Export to AutoCAD tool, where it will turn your MEP objects into proxygraphics. You want to keep that file separate from your production drawings, because they have now lost their MEP intelligence. But it should be good enough for others to view your drawings. If you have multiple versions within the same office, you need to be very careful not to open and save drawings in the new version that users of older versions need to work in. One work around, if you cannot get everybody in the office on the same version, is to work in project teams, where one project will stay in a 2007 format, and other projects will stay in a 2008 format and the users will not open project files that do not match the version they have on their computer.

While this may not be the most idea workflow for companies that have multiple versions in the office, it is what we have to deal with. The best way to deal with this is to make sure everybody who needs to work on the project is using the same version. If that means everybody needs to have the newest version, then companies will need to work on implementing the newest version as soon as they can.

Other programs such as Revit Architecture have been dealing with this issue for years, because RVT files are not backwards compatible at all. So the Revit platform is even worse than AutoCAD as far as backwards compatibility, but companies have been diligently upgrading and working with Revit projects and sharing them more and more each year.

So try not to look at improvements in the technology and the limitations that it brings as a bad thing. Programs evolve, and people adapt, and it's a continuous game that we will always be playing.