Revit 2010 has a two (2) mile maximum distance restriction in any axis for a successful CAD link or import.
This limit reduces potential inaccuracies that a large drawing space can generate. These inaccuracies have been an issue for a long time. Autodesk attempted to limit the problem by restricting the link or import file size.
When you are working with civil drawings and developing large master plan projects, you may need to link a file that exceeds the limits. Manipulating Import Units is a simple solution that does not involve relocating geometry in the linked file and does not require splitting the file into separate sections. Follow these simple steps and your problem is solved.
- Open the CAD file, purge everything and zoom the extents. If this is a consultant file that will be updated regularly as your project progresses, we do not recommend any additional preparation. If this is a file controlled within your organization exclusively, remove all geometry and annotation you do not need in the link. Depending on the file complexity and your ultimate goal, you may want to flatten selected geometry or relocate the geometry closer to 0,0,0 but this is not required. Save and close the file.
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From the Link CAD Formats dialog box, change the Import Units. (If your file was created with Imperial units, Auto-Detect will import feet and inches. If your file was created with Metric units, Auto-Detect will import millimeters. Our example uses Imperial Units.) Assume you are linking a site plan with 9’-0” parking stalls. Change the Import Units to millimeters and your file will import with the stalls at 9 millimeters. Click Open.
- If you get the same message that Revit cannot import the drawing, try setting the Import Units to Custom factor: and reduce the size until you no longer get the warning.
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Once the link is in your Revit model, scale the linked CAD file using a reference dimension you are confident is correct.
