With AutoCAD 2019, comes the drawing Compare feature. (Click here for more information on COMPARE in AutoCAD 2019) In vanilla AutoCAD, COMPARE allows a visual comparison between different versions of the same drawing. If those drawings have MEP or ACA objects you will get incorrect results.
If you are using the MEP (AutoCAD MEP) or Architecture (AutoCAD Architecture) toolsets, the COMPARE works differently. Rather than reflect the changes between drawings, the comparison is between objects. Please see this article for more information.
If you want to perform a drawing comparison similar to vanilla AutoCAD's function, please utilize DWGCOMPARE.
John Vellek
Join the Autodesk Customer Council - Interact with developers, provide feedback on current and future software releases, and beta test the latest software!
Autodesk Knowledge Network | Autodesk Account | Product Feedback
