Section Box for Autodesk® Revit® allows you to incrementally move each of the six sectioning planes (Top, Bottom, Front, Back, Left and Right), giving you an immediate visual of your sectioning.  You can also select a point in your model to locate any of the six planes.  Sectioning can also be done by Level, by Grid Lines or by Rooms.

Note: This app uses a custom installer (and not the standard App Store installer).