OverCAD Dwg Compare allows you to finds differences between versions of AutoCAD drawings and displays them graphically. Find the differences between two DWG. Display the differences using contrasting colors. Choose your own markup colours. Save the differences to separate files. Synchronism zoom,location. Detail list. Compare specially entities. Save compare result. Ignore layers,text height,z-axis,color, linetype.
Version 2 can compare two directories and the layout is more convenient.