The layers you have selected contain both contour lines and non-contour lines (lines of non-constant elevation). You may want to go back and select fewer layers, or you can continue, but the boundary of the site may be larger than you want.
Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.2.0.0 (26.2.0.0)
Syntax
C#
public static FailureDefinitionId ContoursNoncontours { get; }