By Dennis Collin
A common question I often receive are questions on AutoCAD drawings crashing on save, edit or publishing functions. This can be down to corrupted drawing files (See end of article for additional links) But it can also be down to a poorly maintained file which requires a little maintenance.
As a rule, most 2D drawings, provided they are well maintained and are edited in a disciplined environment should have a file size no more than 1MB. However, I occasionally encounter drawings that exceed this size by several orders of magnitude, in one instance a site drawing for infrastructure was more than 50MB!
I often get asked why drawings get into such a state, and to be honest it’s down to many reasons. However, typical causes are the drawing has been passed between numerous consultants or 3rd parties and at each stage has been edited and resaved, the drawing may have been modified or created with a non-Autodesk product or the file originates from a very old DWG format or has been vectorised from a scanned image drawing.
Common symptoms with large files are slow opening, export and save times, sluggish performance when panning or zooming, and occasional crashing.
In a separate post I talked about fixing corrupted files, but sometimes the drawing reports it is fine formatting wise, it’s just bloated with superfluous information.
If this is the case, we can put our drawing onto a diet and feed it the following commands.
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Purge – Think of this command as a spring clean tool. Overtime AutoCAD drawings can get a little untidy. This command gets rid of any unused definitions including blocks, layers and other information that is not required in the drawing file.
- Overkill – To be used with caution, but this command deletes duplicate entities placed on top of each other, this issue is often caused by bound external reference files and edits made to the drawing by novice or untrained users.
- Erase (ALL) and Remove Crossing Elements trick. Sometimes the purge command doesn’t clean the drawing as much as required. So, a second level of cleaning can be applied by using the Erase command, Select All elements, then switch to remove elements mode and lasso around the critical drawing elements that need to be retained within the drawing. There is often a discrepancy between the totals of the 2 selected values, which will be the desired elements that need to stay within the drawing.
Look for exploded hatch elements and dimensions, these elements should be deleted and if necessary recreated. Exploded hatch fill elements are another major reason for excessive file size.
Once these operations have been applied, check the number of layers and entities in the drawing. The total number of items should be greatly reduced. As an additional benefit drawing performance should improve in terms of navigation response and open and save times.
Another benefit is the reduced file size. Not only are file operations smoother and faster, but the file is far easier to transmit, publish, plot and export. Exporting to the Cloud or as an email attachment or data transfer should only take seconds.
Whilst these commands will make a drawing leaner and more efficient, it is worth also checking the drawing units, especially if issues are apparent with line type patterns not showing or recipients claiming that the drawing is the wrong size.
To check out a drawing’s file integrity click here.
For issues with drawing units, annotation, and scale, here.