AutoCAD files include both DXF and DWG formats. You can import
AutoCAD files from version 2.5 through version 2007. During import,
you can specify scale, unit mapping (custom unit for interpreting
all the length data in the AutoCAD file), whether to scale lineweights,
which layout to import, and whether to center the artwork.
Illustrator supports most AutoCAD data, including 3D objects,
shapes and paths, external references, region objects, spline objects
(mapped to Bezier objects that retain the original shape), raster
objects, and text objects. When importing an AutoCAD file that contains
external references, Illustrator reads the contents of the reference
and places it at the appropriate locations in the Illustrator file.
If an external reference is not found, the Missing Link dialog box
opens so you can search for and retrieve the file.