RPURGE — The AutoCAD purge that works

Why PURGE is not enough

AutoCAD's native PURGE command is conservative by design: it refuses to delete anything that could potentially be used somewhere. The result: it leaves residues that are invisible but costly in file size:

• Ghost layers — layers with no visible entities but referenced in dictionaries
• Unused text and dimension styles — including variants created by WBLOCK/XREF
• Obsolete RegApps — registered applications left behind by uninstalled plugins
• Orphaned DGN/PDF dictionaries — leftovers from old file imports
• Anonymous BTRs (*U####) — dynamic blocks whose parent has been deleted
• Custom scales — added by third-party plugins
• Frozen proxy entities — leftover objects from vertical applications

How RPURGE works

RPURGE runs 10 successive purge passes until stabilisation (no further purge possible). Between each pass, it actively cleans:

1. Standard purge (styles, layers, linetypes, unused blocks)
2. Removal of unused RegApps (except dynamic whitelist)
3. Cleanup of orphan dictionaries (DGN, PDF, ghost images)
4. Purge of dereferenced anonymous BTRs
5. Cleanup of unused scale definitions
6. Removal of redundant system variables
7. Purge of empty symbol tables
8. Final audit to guarantee consistency

Protection of dynamic blocks

AutoCAD dynamic blocks use extension dictionaries (ACAD_ENHANCEDBLOCK) and anonymous BTRs (*U####). A naive purge can break these links and produce orphan blocks (the infamous *U1234 which appear everywhere). RPURGE protects these structures by checking transitive references before each deletion.

If needed, ElectroCAD also provides the command ECREPAIRBLOCKS to repair broken dynamic blocks and ECDIAGBLOCKS to diagnose *U references.

Use

# In AutoCAD, command line: Command: RPURGE # RPURGE automatically runs 10 passes # The report shows what was removed on each pass
    

No options, no dialog box. Run it, wait a few seconds, and your file is cleaned.

Typical results

• Loaded project DWG file going from 45 MB → 8 MB (82% reduction)
• Opening time divided by 3 or 4
• Removal of ghost layers that appeared after XREF/import
• Removal of RegApps left behind by old plugins