Finally…Drawing Compare inside of AutoCAD!

We’ve all been there! Two drawings that look eerily similar but you’re not quite sure if they are exactly the same. What is the difference between the two drawings (if any?) Without a drawing comparison capability…how can you tell? No problem…AutoCAD 2019 to the rescue!

Until now, you might have chosen to use Design Review or perhaps BIM 360 to compare one AutoCAD drawing file to another. Now, however, there is a great new tool built right into AutoCAD: DWGCOMPARE. Let’s take a look:

If you don’t have any drawing files open and you go to the Application Menu – you’ll find DWG Compare is easily found and accessible as seen below in Figure 1.

*Figure 1: DWG Compare can be found in the root Application menu when no files are open.*

If you have already opened a drawing file, you can still find DWG Compare in the Application Menu under Drawing Utilities. You’ll also find it on the new Collaboration tab on the ribbon as seen in figure 2 – which, incidentally, I find ironic since there was probably a big LACK of collaboration that led you to need to compare two drawings to begin with!

*Figure 2: DWG Compare can also be found on the new Collaborate tab on the AutoCAD ribbon.*

Regardless of how you decide to execute the DWG Compare command (you may even choose to key it in at the command line with DWGCOMPARE), you should find the process quite straight forward and easy. By default, AutoCAD will use your current drawing as one of the drawings you are using to compare. You can easily select a different one by picking on the ellipsis. Then It’s simply a matter of selecting the second drawing you wish to compare as seen in figure 3.

*Figure 3: Select the two drawings you wish to compare.*

You also have the option of controlling the comparison colors for the two drawings. The default colors are green and red – fairly standard colors (except that in my design experience red is always bad!) Choose the colors that work for you here and then Voila! Select the Compare button to make the magic happen!

In my scenario – you’ll find the object differences from drawing 1 will be denoted in the color green and those from drawing 2 will be denoted in red. The objects that are the same in both drawings will be denoted by the color gray as seen in figure 4.

*Figure 4: Drawing Compare uses colors to denote the differences/similarities between drawing files*

On the DWG Compare ribbon you will find a Draw Order option to control which comparison is on top. You can also control the visibility of the various drawing objects by selecting the lightbulbs as seen in figure 5.

*Figure 5: Control visibility of the compared objects from the Comparison panel.*

You might want to add a table with the drawing information into the drawing file for reference. If so – simply select the Drawing Information tool and you’ll find an option to insert the info into the drawing as seen in figure 6.

*Figure 6. You can add a table with the drawing compare information into the drawing for reference.*

You have options to include text and hatching during the compare process as seen in Figure 7. You can also easily turn the revision clouds on and off. By default, DWG Compare will display rectangular revision clouds (which can be quite large and all encompassing). You might prefer to switch to polygonal revision clouds to more clearly indicate the drawing differences…the choice is yours! Regardless of your revision cloud option – you can also control the margin around the compared objects and the revision cloud with the Margin slider bar.

Now I REALLY love the arrows in the Change Set panel that allow you to step through each of the drawing differences to ensure you don’t miss any of them! Otherwise it might be easy to miss a minor one (another reason to turn Revision clouds on).

*Figure 7. Control the various compared object filters as well as the revision clouds from the DWG Compare ribbon.*

You will find that once you do the DWG Compare, AutoCAD creates a new drawing file entitled “Compare_(drawing 1)_vs (drawing 2)” . This will prevent you from accidentally overwriting either of your drawings (and perhaps creating an even bigger mess!).

Figure 8. AutoCAD automatically assigns a new name to the comparison drawing file.

I absolutely love the way Autodesk wrote this new DWG Comparison tool. It’s simple, straight forward, and gets the job done quickly and easily. So the next time you’re in a bind and you can’t quite figure out the difference between two drawing files – give DWG Compare a try! You might just find it saves you hours of tedious work.

Lynn Allen

In her career as Technology Evangelist, Lynn Allen has spoken to more than a half million design professionals in over 50 countries throughout the world. Her online reach over the years easily reaches in the millions. An early CAD entrepreneur, Lynn taught AutoCAD at the corporate and collegiate level for 10 years before joining Autodesk. A popular columnist for Cadalyst magazine for over two decades, she is the face behind hundreds of software videos including the series “Tips and Tricks with Lynn Allen”. A sought-after public speaker with a unique comedic style, Lynn was the host of Autodesk University for over a decade and is always one of the highest rated presenters at the many worldwide Autodesk Universities. She is also the author of three technical books focused on Autodesk software. Lynn has been a global driving force in moving 2D CAD users to Digital Prototyping and BIM.