This node will allow you to check what Floor, Wall, Roof, Ceiling and Room elements are owned by a particular level. This node will work in both 2D and 3D views.
You have the options to isolate the elements, colour the elements and reset aforementioned colouration.
Note: If the isolation element isn’t working, it’s most likely due to conflicting Clockwork packages.
Dependent packages: Spring Nodes and Clockwork
Dynamo Nodes 
This still seems to have issues in 0.9.1 and Revit 15. The color override isolation does not seem to reset. I made a specific 3D view but this does not always seem to isolate elements in that view. It will recolor elements in the default 3D view, but as I said will not reset colors.
Hey Tom, this is working for me at present. I had to, however, completely remove and re-install the Clockwork package to get it to do so (Probable conflict errors). Could you try that?
Hello Tom,
This is working for me correctly after fully uninstalling and reinstalling the ‘Clockwork’ package. There was some form of conflict error if multiple variants were installed. Could you try that?