Problems with revising proposed surface

[devsi96]

I had a proposed surface in Civil3D2010 that was fine,  made revisions to the proposed contours using grips or deleting/adding contours. Now when I  try to add the new contour data to the surface either the program hangs up or I get contour error messages and the surface never gets re-built. Has this happened with anyone else, or any suggestions to get around it?

[jmayo-EE]

I would wonder if

1. Your surface is processing the data in the order you expect. Surface properties dialog, definitions tab.

2. If the contours you added we crossing or interfering with old surface definition data. Confirm the old data is removed from the surface, rebuild and then add new data.

3. If the contours you added have issues like overlapping, duplicate or zero length objects.