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    By Dennis Collin

    AC Purge 1.png

    I recently had a question from a customer who had a block that would not purge from a drawing. It was an old title sheet that had been subsequently updated but the old definition would not appear on the purge-able items list.

    AC Purge 2.png

    Fig 1. A common support question is how to purge unused elements within a drawing.

    When a drawing has empty layers or block definitions that have not been placed within a drawing, AutoCAD should be able to purge them from the drawing thereby streamlining the drawing in terms of file size and maximise efficiency.

    In the example in Figure 1, a Cadline_A1_Titlesheet does not exist as a placed element in the drawing, yet it does not appear within the Purgeable items list. But strangely, the block entry does appear within the Rename elements command dialogue.

    AC Purge 3.png

    Fig 2. Unused non purgeable block appears in block rename list.

    The reason for the inability for blocks to purge from a drawing file is usually that they reside as a nested component of a block that is in use. However, if the block is an Anonymous block (i.e. a block without a properly defined name) the issue can be a little troublesome to resolve, as the anonymous block having no proper name can be difficult to locate!

    AC Purge 4.png

    Fig 3. Locating the cause of the non-purgeable block.

    This is confirmed by revisiting the Purge command and enabling the list of elements within a drawing that cannot be purged. The Cadline A1 Sheet appears, and AutoCAD reports the reason as suspected that the offending block resides within an anonymous block “A$C72a2a4a7”. 

    Purging this anonymous block by locating it and deleting it from the drawing will then enable the superseded title block element to be purged from the drawing as well.

    AC Purge 5.png

    Fig 4. Have problems locating elements, use AutoCAD’s powerful Quick Select tool!

    Drawing maintenance, clean-up and the following of best practices are just some of the topics that we can cover on our more advanced or intermediate courses. For more information on the courses that we offer visit https://training.cadline.co.uk/ or ask a question on the sites’ chat facility where a member of the team will be able to help.