What exactly does "Compact File" do?

[patricks]

I have a worksetted file that was up around 23MB or so, and yesterday I STC and checked Compact Central File which took it down to 15MB, and then purging all unused objects took it down to 10MB. Now my local file was still around 23MB so today I did a Save As, kept the same file name, but checked Compact File in the Save As options, and that also took my local file down to around 10MB just like the central file.

I'm just wondering what sorts of baggage are these Revit files storing that it seems to toss out when you tell it to compact the file? It is a nice feature to have, that's for sure.

[gibson.tim]

If I understand correctly what others have said in the past, a trade off of the speed increase when saving to central in 8.1 is file fragmentation. So compacting the central file when saving essentially defragments the file (like a windows defrag). Compacting the central file tosses all the "padding" between data in the file.

[patricks]

Ah I get it.... to me it seems like a win-win situation. We get faster save and STC times, and then we can also run the compact function every now and then to at least make us think that the file is becoming alot smaller, which always makes me feel good about Revit in general. :D

[bowlingbrad]

From what I've heard, I think it's just a tool to save hard drive space. It is a compaction of the CF. This creates longer open and save times because it has to uncompact and recompact.

[irwin]

From what I've heard, I think it's just a tool to save hard drive space. It is a compaction of the CF. This creates longer open and save times because it has to uncompact and recompact.
Actually, after compacting the file it should be slightly faster to open and save. The only reason the file isn't compacted on every save is that compacting itself takes time. Thinking of compacting the file as being like cleaning up your office: after you clean it up its faster to find things, but you wouldn't want to clean it up every time you put something down -- instead just clean it up once in a while when it gets cluttered.

[dfriesen]

Actually, after compacting the file it should be slightly faster to open and save. The only reason the file isn't compacted on every save is that compacting itself takes time. Thinking of compacting the file as being like cleaning up your office: after you clean it up its faster to find things, but you wouldn't want to clean it up every time you put something down -- instead just clean it up once in a while when it gets cluttered.Is Patrick's process of Compacting when save to central, and then Compacting local file using SaveAs the best way to go?

[Wes Macaulay]

Good point Daniel -- you can't compact your local file unless you choose File > Save as. I guess the idea is that saving locally is pretty fast, so you don't have as much to gain from compacting your local file. But over the network any speed increase helps, so the STC dialog got the compact option built in.