About Comparing Differences Between Drawings

Use the DWG Compare feature to compare two drawings. Color and revision clouds are used to show the differences.

As your design progresses, it becomes more difficult to remember what was changed from one revision to the next, especially when working in a remotely distributed team. The DWG Compare feature provides a way to perform a visual comparison between two drawings.

During the comparison process, DWG Compare feature identifies objects that have been modified, added, or removed from the two drawings. The result displays in a new drawing called the comparison drawing. The name of the comparison drawing is a combination of the file names of the compared drawings, Compare_filename1 vs filename2.dwg. In the comparison drawing, the differences are highlighted as change sets, using revision clouds. Revision clouds are placed on a new layer, 0-Markups, in the comparison drawing.

Three colors in the comparison drawing highlight the common objects and the differences. You can specify colors to identify the following:

Note: If you have a layer that is turned off or frozen in DWG 1, it will not become part of the comparison result.

Unsupported Object Types

DWG Compare does not support the following object types for drawing comparison:
  • OLE objects
  • Camera
  • Geographic data
  • GIS objects created in AutoCAD Map 3D
  • External References of the following types: DGN underlays, DWF underlays, PDF underlays, Images, Coordination models, and Point clouds

Limitations

The limitations for the DWG Compare feature include the following:
  • Operates in model space only. If a drawing selected for comparison was saved in a layout, DWG Compare automatically switches to the Model tab.
  • Supports DWG files only.
  • Does not support using a comparison drawing to compare against another drawing.
  • Cannot detect ByBlock or ByLayer property changes for nested objects. For example, if you have a block named chair and a block named table and these blocks are inside another block definition called dinner set, then the chair and the table blocks are called nested objects. When the property of the nested object, in this case the chair or the table, is set to ByBlock—the property for the nested object is not detected even when the top-level object, in our case the dinner set, is modified.
  • Comparison graphics are displayed only in the 2D Wireframe visual style.
  • Revision clouds cannot enclose changes in an isometric view.