Revit was built as a 3D modeling program and as such you are presumably using it for that. Exploding a dwg with many thousands of items would generally defeat the purpose of Revit since the point is to draft in the 3rd dimension not just the 2nd. Exploding a 2D dwg file will give you a ton of 2D items, but will do nothing for modeling the drawing. Not to mention the database structure of Revit is very different than AutoCAD and what might be a very manageable file size in ACAD can get way out of hand in Revit if you have too many items in it.
All of that said My suggestion is to underlay the dwg from the "file" menu and the "import/link cad format" option. This way you can still use the ACAD drawing as a base and trace over it. Revit gives you a handy little copy tool that allows you to simply click on a line and trace the entire items all at once, works great for creating walls, etc. in a hurry.
I would recommend linking the file rather than importing it. This way it works more like an "xref" than a "block" speaking in AutoCAD terms, and will allow you to make changes to the dwg underlay and push them through to Revit. I would also consider the "this view only" option so that you don't have a cad underlay in a bunch of different views, which can really slow down the system. Linking the file also gives you the added functionality of being able to turn the file on and off in visibility graphics (type "VG" on the keyboard, and select imported categories).
If for some reason you still need to explode that DWG:
While I wouldn't recommend it, you could WBlock out certain logical sections of your DWG file and import each separately. Run the audit command on the new dwg block file that was created to see how many items are located in the file prior to importing it to Revit. Be sure to pick one common "anchor point" and include it with each block so that you can put your model back together in revit.
Cameron Piper
BWBR Architects
St Paul, MN
Message was edited by: CPiper
