Ever had that annoying problem of your entire dwg showing up in Section Views, regardless of where it is cut? If so, check out this tip from Chad at Revit KB:
…if you link the DWG into an In-Place Mass instead, then when the section cuts through the Mass/DWG it will only show just the elements which are being cut by the section.

when placed inside a Mass, that Mass can then be Phased which also means the DWG inside it will too.

via
https://plus.google.com/app/basic/stream/z12zslgqpmqedbufj22wxlrybve1xpb0i