By John Flanagan
DWG Compare Tool
The drawing compare tool was introduced to AutoCAD in the 2019 version, developed to help users identify differences between drawings, whether it is comparing revisions or just comparing similar drawings.
Once you start the Compare command, which is found on the View tab of the Ribbon, you are asked to browse to the drawing you wish to compare your open drawing with.
In the Select a Drawing to Compare dialogue box, specify the drawing file that you want to Compare with the current drawing and click Open.
The DWG Compare toolbar opens and the comparison results display in the current drawing. This toolbar provides several commands and options to review and control the comparison result.
The wheel cog icon allows you to adjust the settings of the comparison, for example changing the display colours.
By default, the colours are assigned as follows:
- Red - Objects that are only in the compared drawing.
- Green - Objects that are only in the current drawing.
- Gray - Objects that are common to both drawings.
Change the settings and decide the colour of the items that are ‘Not in Current Drawing’, ‘Only in Current Drawing’ and where there are ‘No Differences’ at all. You can also change the colour of the revision clouds.
In the example below a furniture layout drawing has been altered. Using the Drawing Compare command, a different version of the drawing can be selected, and AutoCAD will highlight the differences where elements have been added, deleted, or changed.
The light bulb icon turns on or off the display of the various items in the comparison. In the image below I have turned off the display of the revision cloud and the display of the objects that show ‘No Differences’.
The arrows that point to the left and to the right allow you to scroll through the differences, as you scroll through each difference the software will automatically zoom to each difference.
The import tool enables the transfer of objects from the old drawing into the current drawing.
To clear the drawing compare graphic, simply click the green tick icon. Should the drawing need to be compared later rerun the DWG Compare command from the Ribbon menu or type ‘Compare’ at the command prompt.
In AutoCAD 2022 the drawing compare capability was improved to work with changes to external reference files. Should a link file be updated, the host drawing will display a bubble notification. Once acknowledged and applied a similar view shows with the altered elements within an Xref being highlighted.