Revit 2018 comes recently with some new features in all disciplines But, not all features are mentioned in the "what`s new list".
One of those new hidden feature is the ability to export views/sheets in Revit to AutoCAD without any changes in colors or patterns, which was not allowed before in Revit 2017.
Even Room colors and objects transparency can be exported to AutoCAD exactly the same in Revit.
Check this screen shots below for the same view in revit and autocad exported with this new option.
We will keep exploring the new feature and share it.
This feature is also available in Revit 2017 after installing the 2017.2 update, check the direct link below.
Download link: http://up.autodesk.com/2017/RVT/Autodesk_Revit_2017_2.exe