AutoCAD file save process

Autodesk Support

Oct 8, 2023

Products and versions covered

Issue:

What are the steps that AutoCAD goes through to save a drawing?

Solution:

Given initial files on disk: Model.DWG and Model.BAK:

Opening a drawing

  1. OPEN the Model.DWG.
  2. Model.DWG is loaded from disk into RAM.
  3. Model.DWL (WhoHas file) created.
  4. Model.DWL2 (XML version of WhoHas file) created.
Note: No .tmp is created on OPEN.

Full save

  1. Full SAVE (occurs if ISAVEPERCENT=0 and may also occur if ISAVEPERCENT>0).
  2. SAVE the Model.DWG if a full-save occurs and SAVEBAK sysvar is enabled.
  3. Model.DWG in RAM is written out to a .tmp.
  4. Model.BAK deleted.
  5. Model.DWG renamed to Model.BAK.
  6. The .tmp renamed to Model.DWG.
  7. Model.DWG remains in RAM for current session.

Model.DWL & Model.DWL2 remain as-is (files are deleted when user closes Model.DWG).

Incremental save

  1. Incremental SAVE (which may occur if ISAVEPERCENT>0).
  2. SAVE the Model.DWG when SAVEBAK sysvar is enabled.
  3. Model.DWG copied to a .tmp.
  4. Model.DWG edits (changes currently in RAM since last save) are written incrementally the .tmp.
  5. Model.BAK deleted.
  6. Model.DWG renamed to Model.BAK.
  7. The .tmp is renamed to Model.DWG.
  8. Model.DWG remains in RAM for current session.
Note: 
  • Save performance is improved in AutoCAD 2018 and later. Objects that will experience the greatest improvement include blocks with annotation scaling, mtext with columns and other newer formatting, as well as attributes and attribute definitions with multilines.
  • An automatic save does not save the current drawing, a temporary file with the extension .sv$ is generated instead. Automatic saves (auto save) are only created if a drawing has been modified after the last save. Automatic save functionality is most often performed incrementally rather than a full save. See Understanding backup and autosave files in AutoCAD for additional information.
  • See DWL and DWL2 files are created while working on AutoCAD for additional information on DWL files.

Products:

AutoCAD for Mac; AutoCAD LT for Mac; AutoCAD Products;

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