The information below is an example of the kind of content embedded within Ideate XRay. There are over 50 unique invisibility results possible within the product itself.
A 3D Level line can always be made visible in a Revit Section or Elevation view - DO NOT duplicate the Level line! If the Level line is not visible, the cause is that the plane defined by the 3d Level line does not intersect the extents of the Target View. See below for two methods for resolving a Level line visibility issue using Ideate XRay for Revit.
The more difficult, but recommended solution requires that the ends of the 3d level line are edited to cause the Level to intersect the plane of the Target View.
An easier solution is to set the Far Clip setting of the Target View to "None", as shown. While this will likely resolve the issue, it may end up displaying other elements in the view that are not intended. If this solution does not resolve the issue, then its likely that the Crop Region is also obscuring the Level line. If so, uncheck the Crop Region of the Target View to test.