This tutorial will show you how to isolate elements in Revit and then export them to AutoCAD using Dynamo.
Get the Dynamo script here:
https://www.dropbox.com/s/w24220u5mfg...
Get you Autodesk subscription package here:
https://www.autodesk.com/subscription
Get your free Dynamo plugin here:
http://dynamobim.org/