This is how you can compare AutoCAD drawing changes using drawing compare tool

AutoCAD has the drawing comparison tool that is used to identify the difference between two different DWGs, most preferrable DWGs with the same design, only with a revision or an added feature.

This feature highlights the differences between the two drawing files using specificized colours (mostly green and red) and makes spotting the difference between them fast.

How to use the compare tool in AutoCAD:

The compare tool is found under the collaborate tab, under the compare panel as show in the exhibit below.

To get the most out of this feature, first have an opened drawing of your choice, that you will use it like a base reference.

AutoCAD automatically picks your open drawing as the underlay drawing, and prompts you to pick another drawing to compare it against.

In the DWG Compare window, a gear icon will be visible within the center-upper area of your workspace, as shown above, under it you can change some comparison settings like the colour coding of the comparison elements.

As shown in the exhibit above, colour green highlight represents DWG items that are only available in the current underlaying drawing, colour red highlight if it is missing in the current underlaying drawing, grey if there is no difference between the two drawings (But, you can change the draw order).

From the bulb icon adjacent to the colour code discussed above, you can either choose to hide the three main categories of the drawing from the drawing by either toggling it off (a blue-coloured bulb) or on (a yellow-coloured bulb); this applies to other components under the compare settings.

Moreover, if you would prefer using different colors apart from red and green to represent the DWG differences, you can click on the color icon to get the Select Color window, from where you can select any color of your preference.

The other available option under the gear icon is the revision cloud which make the drawing review experience easier and faster within the software environment or if exported as a PDF or other relevant formats, you can also change the colour, shape and size of the revision cloud with respect to the type of design you are working on.

Another neat feature is that you can adjust if the hatches and/ or texts comparison will be done between the different DWG making the comparison less busy in the even of annotation changes or hatch pattern changes; this can be toggled on or off under the filter area in the DWG Compare settings.

Furthermore, in the main comparison bar settings, you can opt to hide all comparisons done in the view by toggling the bulb on or off as shown in the exhibit below:

AutoCAD allows you to move through multiple compared items that have a difference, you can either move forward or backwards using the direction icons in the main comparison bar setting.

This feature is quite helpful, as it also facilitates zooming in at that particular section where there is a difference between the two drawings.

Another helpful feature found in the main comparison bar setting is the ability to import blocks or objects from the compared drawing, reducing design time and misplacement errors, especially for coordinate-sensitive designs.

Once the option is activated, you are promoted to select the objects that you want to bring into the model, this allows for control of your design work, facilitating the importation of only the approved points.

Finally, once satisfied with the comparison, you can now export the comparison view, by binding it into a new drawing and share it with relevant teams in a .dwg or .dxf format.

This can be achieved in AutoCAD using the Export Snapshot option that is available in the main comparison bar setting as shown in the exhibit below:

Benefits of using the Drawing Comparison tool in AutoCAD

The Drawing Comparison tool in AutoCAD increase design efficiency by eliminating manual comparison of drawing files especially when the design is under continuous development.

This tool facilitates for easier collaboration between multiple design teams as different drawing files can be shared out and comparisons about the specific changes can be observed and adopted into new designs.

Frequently Asked Questions:

Does AutoCAD LT have the Drawing compare tool?

Yes, AutoCAD LT has a drawing comparison feature tool integrated into it. 

You can use it to compare two versions of a drawing file and visualize the highlighted differences then in real time and applying all the features discussed above.

In fact, the drawing comparison feature tool is available for other software like Civil 3D, Plant 3D, etc., that have the AutoCAD engine inbuilt in them.

Can I use the Drawing compare tool for 3D objects in AutoCAD?

Yes, the drawing comparison feature tool can be used to compared 3D objects in AutoCAD but with some limitations like, it can only work within the model space area, it excludes point cloud data, and 2D wireframe view style representation differences.

 items exclude in the 3D comparison incudes and is not limited to, cameras, GIS and OLE objects, Nested blocks, non DWG underlays, etc.

Can I compare more than two drawings in AutoCAD?

No, AutoCAD cannot compare a third drawing. 

AutoCAD only facilitates the comparison of two drawings at a time with the natives’ features are discussed above.

Furthermore, if you need more features, third-party plugins can be used to get more advanced features.

Conclusion

AutoCAD has many features that make it the to go software for most CAD design engineers, and one of them is the Drawing Comparison tool.

This is an essential tool that facilitates collaboration between team seamless, it allows fast checks and interventions when working on the same drawing but different disciples, and the best thing about it is that any one can use it, it is not rocket science, it involves just a few clicks as discussed above.

Let me know if you have even needed to use this tool in your design work or it is a non essential tool that is found in AutoCAD.