DWG Compare Limitations

Drawing comparison does not support all object types in AutoCAD and AutoCAD specialized toolsets.

Limitations for AutoCAD Object Types

The DWG Compare feature does not support all object types in AutoCAD. The exceptions include OLE objects, cameras, geographic data, GIS objects from Map 3D, non-DWG underlays, images, coordination models, and point clouds.

Limitations in AutoCAD Specialized Toolsets

When performing a comparison, importing electrical and mechanical objects is similar to the copy/paste behavior in AutoCAD, which is different from how the AutoCAD Electrical and AutoCAD Mechanical toolsets normally operate. As a result, some of the toolset components lose their custom functionality.

The following tables describe the primary limitations for the comparing drawings created with the AutoCAD Electrical and AutoCAD Mechanical specialized toolsets.

Limitations with the AutoCAD Electrical Toolset

Electrical objects	Output after using compare import command
Wires	Wires will lose some of the properties like color and size. The wire data is available in the project as layers and cannot be imported into the drawing comparison mode.
Wire number	The wire number is disconnected with the wire. The imported wire number will lose the relationship with the wire.
Source/Destination arrows	The source/destination arrows imported will not have the correct wire numbers. The source arrows and the destination arrows will also lose the relationship to each other.
Schematic terminals	These blocks will retain their electrical properties, however the terminal wire numbers will not be updated.
Balloons	The imported balloons will not be grouped and will be available only as exploded geometric objects.

Limitations with the AutoCAD Mechanical Toolset

Mechanical objects	Output after using compare import command
Mechanical symbols	Importing a mechanical symbol that's attached to an object also imports the associated object. For example, if a weld symbol is attached to a rectangle, importing the weld symbol will also import the rectangle object.
Standard parts	Importing a standard part will not update the Bill of Materials (BOM) unless you also select the associated part reference of the standard part.
Finite Element Analysis (FEA) objects and other calculation objects	Importing an FEA object will not include its mechanical data and the object will be imported as a block.

Limitations with the AutoCAD Architecture Toolset

Architectural objects	Output after using compare import command
General AEC objects	Importing an architectural object (AEC object) that's attached to an AEC object also imports the associated object. For example, if a door or window is attached to a wall, importing the door or window object will also import the associated wall object.

Limitations with the AutoCAD MEP Toolset

Architectural objects	Output after using compare import command
General MEP objects	Importing an MEP object that's attached to an MEP object also imports the associated object. For example, if a duct fitting is attached to a duct, importing the duct fitting will also import the associated duct object.