I've often needed to reduce drawing file sizes to a workable size. Especially where multiple users have been chopping on it and haven't kept it clean. Purging doesn't seem to eliminate all the items in memory or something.
This has worked for me. Turn every layer on and copy/paste everyhting into a new drawing template. Make sure to set the units to the correct style. This can be pain if you're working with multiple layouts but saves a lot of time in the long run having to wait for screen regeneration when panning and zooming on a large drawing.
Another thing to consider. The file size doesn't automatically determine the workability of a drawing. I've worked on 3D drawings of 30MB or more that worked fine but then again I have worked on drawings that are only 5MB in file size that are extremely slow. Xref's, raster images, PDF overlays, hatches etc always slow a drawing down. Where 3D drawing assemblies get so large to make the drawing unworkable try to divide it into multiple drawings by type, such as concrete and rebar and then insert as seperate Xref's that way you can load/unload each Xref as needed.
One major lesson I'm sure you have learned is that Revit handles large datasets much more efficiently than does AutoCAD. So does Navisworks. One day we're hoping AutoCAD can learn to deal with larger drawings. It's very annoying when you have what you think is five hours work, but it turns into ten because you're waiting for AutoCAD.
This is a long thread and has gone from AutoCAD to Civil 3D to AutoCAD MEP, so correct me if I am confused.
The drawing was created with AutoCAD MEP 2012. You received it from a co-worker and are trying to use AutoCAD MEP 2013 on this drawing, but it's slow. You say your co-worker can work on it efficiently?
I have possible solution. If you have your 2013 on subscription, you can install and run 2012 on the same workstation. If that's going to get you around your issue, maybe you should consider it. The .dwg database was changed by Autodesk between 2012 and 2013 and that might be causing your problems. Like every other poster to this thread, I'm not sure, but if it was me, this is what I would try first.
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