About Comparing Differences between Drawings

Use the DWG Compare feature set to highlight the differences between two revisions of the same drawing or different drawings.

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 different revisions of the same drawing or different drawings, and review the changes. During the comparison process, the DWG Compare feature identifies objects that have been modified, added, or removed between two drawings. The result displays in a new drawing called the comparison drawing. Two colors in the comparison drawing highlight the differences. You can specify colors to identify the following:

Objects that exist only in the first drawing (DWG 1)
Objects that exist only in the second drawing (DWG 2)
Objects that are unchanged or common to both drawings

All styles and settings in a comparison drawing are copied from DWG 1.

Before you start the comparison process, you must save the current drawing. By default, the default file name for the comparison drawing is Compare_<first drawing name> vs <second drawing name>.dwg.

Layer Status in the Comparison Drawing

In the comparison drawing, the layers from the first drawing (DWG 1) and the second drawing (DWG 2) are named using the following format:

<layer name>_DWG1 and <layer name>_DWG2

In the comparison drawing, the layer status settings for first and second drawings are copied from DWG 1, so you can you filter out unneeded layers in the comparison drawing by default.

NOTE:If you have a layer that is turned off or frozen in DWG 1, it will not become part of the comparison result. You will need to turn the layer on and thaw it for the layer to be included in the comparison.

Unsupported Objects

DWG Compare does not support the following objects during the drawing comparison process:

Coordination models
DGN underlays
DWF underlays
GIS objects from drawings created in AutoCAD Map 3D
Images
OLE objects
PDF underlays
Point clouds

Limitations

he limitations for the DWG Compare feature include the following:

Operates in model space. 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 result drawing to compare against another drawing.
Objects are identified as changed even for objects that have only been shifted.
Cannot detect ByBlock or ByLayer property changes for nested objects.
Objects that were converted to a block are identified as changed.
Comparison graphics are displayed only in the 2D Wireframe visual style.
Revision clouds cannot enclose changes in an isometric view.