Feature lines with zero vertices

[libbyt]

Using Civil 3D 2009, service pack 2.
I've established a surface defined by feature lines and corridors, and a few contours. All was going ok, until recently. I create a polyline, set its elevation in 'properties', then 'create feature line from objects'. That goes fine. Then 'add to surface as breakline', and the surface does not respond. In the prospector, I can select the feature line, and it shows the description, vertices, and type. Getting zero vertices! This is the same process I've used, but it suddenly is no longer working. I can select the feature line and do 'elevation editor' and there ARE vertices. I've also tried adding the same polyline as a contour, also with no result.
Any suggestions? Is there some way to 'purge' a surface, or debug it?

Thanks!
Libby

[brian.hailey933139]

Never heard of that one before. First suggestion would be to audit/recover the drawing.

[libbyt]

I had tried 'recover', and no change.
After much frustration, and for no apparent reason, things starting working as normal again. I did find that under 'surface properties', one can look at all the items/actions that make up the surface. I may have had some deleted feature lines that still showed up in the list. So I deleted them from the list to disassociate these erased features from the surface. Maybe that was bugging it up. Also in that list- just a handy feature- one can uncheck items one at a time and see the difference each one makes in influencing the surface.