By John Flanagan
Linking a CAD file is a physical link – so that should the file change you can reload the CAD file and it will update accordingly.
Any CAD files linked into Revit must follow a careful process:
1- Bind XRefs: Xrefs can cause problems. Open the Xref dialog box and bind them all,
preventing duplicate layers.
2- Run "Purge": This removes unused layers, linetypes, blocks, etc.
3- Run "Setbylayer": All lines settings should be set to layers, ignoring any colour, linetype
or lineweight overrides. Use the Setbylayer command to quickly resolve this problem.
4- Freeze Useless Layers: Freeze all layers not required in Revit.
5- Save A Copy: Keep the original DWG file just in case. Save the modified file in a Revit
"CAD Links" subfolder.
USE LINK CAD, NOT IMPORT CAD
Now that your DWG file is ready, you can bring it to Revit. You will notice that there are two options to bring the DWG file: Import and Link. Avoid using Import CAD. It makes your model heavier, causing performance issues.
Link CAD is better: it loads the latest version of the DWG each time you open Revit and is more efficient to manage the files.