Wood Framing - CAD Base Plans

One of the first things that I noticed when trying to work with CAD plans in a Revit many moons ago was that the CAD plans would block out structural elements like footings and foundations.  After that I was finding Revit elements blocking out CAD objects.  It's been over 9 years since my first Revit project and I've created several iterations of workflow for CAD in Revit and Autodesk has kindly made many terrific updates in that time as well.  So lets have a review of the more recent and simplest workflow yet.

Step 1 -  Clean the CAD file.

You need a cleanup routine to make the job faster and easier.  Either you already have one for cleaning up architectural files for underlay in your CAD projects and can take that a bit further for Revit implementation.  Or you start from scratch.  I suggest getting your friendly IT person on task.  Our custom command arch_underlay will explode every block and purge everything in the file and place all remaining items on one layer of grey color.  We don't typically show all the toilets and sinks etc, so it's standard workflow to delete all undesired blocks prior to invoking the arch_underlay command.  Failing to do so will result in time spent deleting the linework of these undesired elements in the CAD file.

Step 2 - Use the CAD command Overkill.

Overkill will delete duplicate lines / objects remaining on top of each other.  CAD drawings from other drawing software's often have multiples of line elements in the same location.  In the CAD clip example project, there were 1343 elements remaining after arch_underlay was run.  After Overkill was run, there were only 545 element remaining.
Overall, both commands are used together to keep file sizes and object numbers to a minimum. 

Step 3 - Link the CAD file

Yes - Link the CAD.  Reason 1 - The linked CAD file will automatically check for and update at each start up.  Reason 2 - the linked CAD will not bring along additional unwanted linestyles, patterns etc into your revit file. 

Note: the linked CAD file imports into background of your Revit model by default.  I've skipped ahead and placed the linked CAD plan offset from it's proper location (within an already constructed model) to show the result.


Step 4 - Draw order

Selecting the CAD link will give you several options for dealing with it's draw order.  You may notice first, and primarily out of habit, the arrange options on the ribbon.  These will however, have no effect on the CAD link, nor if the CAD was merely a simple insert.  What you really need to edit is the draw layer within the properties.  Here you can change the draw layer to foreground and achieve the desired result.