The Revit Clinic posted tip 7 of 10 in a recent post dedicated to Linking Files
7. 2 mile warning on import
If you receive the "Revit cannot import because it will create a Revit model that is larger than 2 miles across" warning and the CAD file contents appear to be within 2 miles in size, there are 3 items to verify:
- Turn on all layers in the AutoCAD file and zoom extents to ensure there are no stray objects.
- Not only check a top view in AutoCAD but also open an elevation and 3D view to ensure the entire model placement is within a 2 mile area.
- If the CAD file contains AEC objects, ensure to set PROXYGRAPHICS to 1 in the CAD file. This can reduce the occurrence of this warning when these objects are present to ensured they are properly displayed.
Item 3 is a good one to remember since civil files often have these. Keep in mind that any AutoCAD based vertical involved needs to save Proxygraphics, by setting the variable equal to 1 (turns it ON), if you hope to see the geometry in Revit too. In this the context of this warning it is particularly important because even if they aren't visible to us, Revit stills sees that they are there, it just can't display them and they DO affect the file's size/extents.
A fourth possibility exists as well, Blocks. While remote perhaps, blocks can contain additional data that is hidden or forgotten which could result in the file technically being too large to import. Good luck!!