Revit’s approach of an all encompassing file can create some behemoth sized files. How big you might ask, very big. The file size you see on the disk is a compressed file format. When that file is opened in active memory, the RAM used is about 20 times the file size. You can check that using Windows Task Manager. From the first submission (typically Design Development or DD’s) to 100% Construction Documents (CD’s) expect a growth factor of about 3 times the DD file size. Let’s put some numbers on this… my office is currently working on a large project, about 300,000 Sqft. The architectural and structural files that are each linked into the project represent the MEP model’s memory overhead. Together these two files are measuring about 200 Megs. Well, 200 Megs X 20 = 4 gigs of ram in use. Then there are the MEP models that currently about 160 Megs x 20 = 3.2 gigs. We are currently at our first submission, and are totaling 7.2 gigs of RAM being utilized. By CD’s it will likely be about 7.2 x 3 = 21.6 gigs. That is a lot of memory to have open at one time. Does this mean you can’t open a Revit file if it requires more RAM than is installed in your computer? Not at all. It will do it’s best to open the file. First it will fill up your available RAM, and then start cashing to your hard drive. That is when you watch the “busy” wheel in windows start grinding away at your profits. There are some Strategies that will help manage the memory being used.
They include :
